Embryology of the Eye - Simplified

1. Regarding the embryology of the lens: There are two
anatomic structures we must concern ourselves with…
Eye embryology made simply ridiculous
1

2. Surface Ectoderm cells resting on the outer body wall of the embryo
(Cell apices)
(Inside of embryo; space filled with embryo stuff)
This is the outer body wall of the embryo in the region
destined to become the head. The surface of the outer
body wall is lined with surface ectoderm cells.
(Outside of embryo; space filled with amniotic fluid)
Eye embryology made simply ridiculous
two words
same two words
2

3. Surface Ectoderm cells resting on the outer body wall of the embryo
(Cell apices)
(Inside of embryo; space filled with embryo stuff)
This is the outer body wall of the embryo in the region
destined to become the head. The surface of the outer
body wall is lined with surface ectoderm cells.
(Outside of embryo; space filled with amniotic fluid)
Eye embryology made simply ridiculous
3

4. Neuroectoderm cells
resting on the inner wall
of the optic vesicle
(Cell apices)
This is the optic vesicle, an outpouching of
the neural tube. The inner surface of the optic
vesicle is lined with neuroectoderm cells.
Eye embryology made simply ridiculous
This way to the
neural tube
one word
same word
4

5. Neuroectoderm cells
resting on the inner wall
of the optic vesicle
(Cell apices)
This is the optic vesicle, an outpouching of
the neural tube. The inner surface of the optic
vesicle is lined with neuroectoderm cells.
Eye embryology made simply ridiculous
This way to the
neural tube
5

6. Neuroectoderm cells
resting on the inner wall
of the optic vesicle
This is how the surface
ectoderm and optic
vesicle are spatially
related early in
embryogenesis.
Eye embryology made simply ridiculous
This way to the
neural tube
(Inside of embryo)
(Outside of embryo)
(Inside of embryo)
(Outside of embryo)
(Inside of embryo)
(Outside of embryo)
6

7. The proximity of the optic
vesicle to the surface
ectoderm induces
those cells to grow
taller, forming a
structure known as
the lens placode.
Lens placode
Eye embryology made simply ridiculous
two words
same words
7

8. The proximity of the optic
vesicle to the surface
ectoderm induces
those cells to grow
taller, forming a
structure known as
the lens placode.
Lens placode
Eye embryology made simply ridiculous
8
*
*aka lens plate
*

9. The proximity of the optic
vesicle to the surface
ectoderm induces
those cells to grow
taller, forming a
structure known as
the lens placode.
This occurs in the
first month of
embryogenesis.
Lens placode
Eye embryology made simply ridiculous
unit of time
9

10. The proximity of the optic
vesicle to the surface
ectoderm induces
those cells to grow
taller, forming a
structure known as
the lens placode.
This occurs in the
first month of
embryogenesis.
Lens placode
Eye embryology made simply ridiculous
10

11. The optic vesicle starts
to invaginate, and…
Eye embryology made simply ridiculous
11

12. The optic vesicle starts
to invaginate, and…
as it does, the lens
placode follows.
Eye embryology made simply ridiculous
12

13. This process of
invagination/following
continues…
Eye embryology made simply ridiculous
13

14. This process of
invagination/following
continues…
and continues…
Eye embryology made simply ridiculous
14

15. This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
Eye embryology made simply ridiculous
15

16. This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
Eye embryology made simply ridiculous
16
At this stage, the
former optic vesicle
is now called the
optic cup.
two words

17. This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
Eye embryology made simply ridiculous
17
At this stage, the
former optic vesicle
is now called the
optic cup.

18. Eye embryology made simply ridiculous
Note that the surface ectoderm re-establishes a continuous body wall
This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
18
At this stage, the
former optic vesicle
is now called the
optic cup.

19. This part will
become the optic nerve
Eye embryology made simply ridiculous
two words
This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
Note that the surface ectoderm re-establishes a continuous body wall
19
At this stage, the
former optic vesicle
is now called the
optic cup.

20. This part will
become the optic nerve
Eye embryology made simply ridiculous
This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
Note that the surface ectoderm re-establishes a continuous body wall
20
At this stage, the
former optic vesicle
is now called the
optic cup.

21. At this stage, the
former optic vesicle
is now called the
optic cup.
This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
This part will
become the optic nerve
Eye embryology made simply ridiculous
Note that the surface ectoderm re-establishes a continuous body wall
The re-established surface ectoderm will eventually give
rise to a number of eye-related structures:
1) ? of the conjunctiva
2) ? of the cornea
3) ?
4) ? gland
21

22. At this stage, the
former optic vesicle
is now called the
optic cup.
This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
This part will
become the optic nerve
Eye embryology made simply ridiculous
Note that the surface ectoderm re-establishes a continuous body wall
The re-established surface ectoderm will eventually give
rise to a number of eye-related structures:
1) Epithelium of the conjunctiva
2) Epithelium of the cornea
3) Eyelids
4) Lacrimal gland
22

23. At this stage, the
former optic vesicle
is now called the
optic cup.
This process of
invagination/following
continues…
and continues…
until the two walls
of neuroectoderm
are apposing,
and the surface
ectoderm has
formed a sphere.
This part will
become the optic nerve
Eye embryology made simply ridiculous
Note that the surface ectoderm re-establishes a continuous body wall
The re-established surface ectoderm will eventually give
rise to a number of eye-related structures:
1) Epithelium of the conjunctiva
2) Epithelium of the cornea
3) Eyelids
4) Lacrimal gland
23

24. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
The invaginated neuroectoderm
gives rise to the:
1) retina
2)
3) epithelium
(both pigmented and nonpigmented layers)
4) epithelium (posterior)
5) sphincter muscle
6) dilator muscle
Eye embryology made simply ridiculous
24
[Technically two words, but goes by one]

25. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
25

26. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2)
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Note that the embryology explains why the neurosensory retina is upside down in the eye.
Eye embryology made simply ridiculous
26
down
upside

27. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
27
[Three words, but goes by three letters]

28. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
28

29. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
(This part becomes the optic nerve)
Note also that the embryology explains why the RPE and receptor cells are arranged apex-to-apex
Eye embryology made simply ridiculous
29

30. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Also, the embryology explains why rhegmatogenous retinal detachments occur. The neurosensory retina
and RPE are not attached to one another, but rather are separated by a potential space—the remnant of
the space contained within the optic vesicle. Breaks in the retina allow syneretic vitreous to gain access
to this space—and the result is a rhegmatogenous RD.
Eye embryology made simply ridiculous
30

31. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Also, the embryology explains why rhegmatogenous retinal detachments occur. The neurosensory retina
and RPE are not attached to one another, but rather are separated by a potential space—the remnant of
the space contained within the optic vesicle. Breaks in the retina allow syneretic vitreous to gain access
to this space—and the result is a rhegmatogenous RD.
Eye embryology made simply ridiculous
What does rhegmatogenous mean in this context?
It means ‘associated with a break or tear’
What does syneretic mean in this context?
It means ‘liquified’
31

32. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Also, the embryology explains why rhegmatogenous retinal detachments occur. The neurosensory retina
and RPE are not attached to one another, but rather are separated by a potential space—the remnant of
the space contained within the optic vesicle. Breaks in the retina allow syneretic vitreous to gain access
to this space—and the result is a rhegmatogenous RD.
Eye embryology made simply ridiculous
What does rhegmatogenous mean in this context?
It means ‘associated with a break or tear’
What does syneretic mean in this context?
It means ‘liquified’
32

33. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
33
Next question
[Three words]

34. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
34

35. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
35
something
its opposite

36. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
36

37. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Note that the embryology explains
why the ciliary body has two
epithelial layers that also are
arranged apex-to-apex
Eye embryology made simply ridiculous
37

38. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
One CB epi layer is pigmented,
and one isn’t. Which is which?
The inner (nearest the lens) layer
is nonpigmented; the outer (next
to the CB stroma) is pigmented.
Note that the embryology explains
why the ciliary body has two
epithelial layers that also are
arranged apex-to-apex
?
Eye embryology made simply ridiculous
38

39. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
One CB epi layer is pigmented,
and one isn’t. Which is which?
The inner (nearest the lens) layer
is nonpigmented; the outer (next
to the CB stroma) is pigmented.
Note that the embryology explains
why the ciliary body has two
epithelial layers that also are
arranged apex-to-apex
Eye embryology made simply ridiculous
39

40. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Note how the embryology
can help you remember this,
because the pigmented CB
epi is continuous with the
(heavily pigmented) RPE,
while the nonpigmented CB
epi is continuous with the
(largely nonpigmented) retina.
One CB epi layer is pigmented,
and one isn’t. Which is which?
The inner (nearest the lens) layer
is nonpigmented; the outer (next
to the CB stroma) is pigmented.
Eye embryology made simply ridiculous
40

41. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
41
Next question
[Another epithelium]

42. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Posterior epithelium of the iris
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
42

43. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Posterior epithelium of the iris
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
43

44. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Posterior epithelium of the iris
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Note that the embryology explains why the iris has two epithelial layers that
are arranged apex-to-apex, but it is less helpful for remembering that
both epithelial layers are pigmented (you’re on your own for that fact!).
Eye embryology made simply ridiculous
44

45. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Posterior epithelium of the iris
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
45

46. The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium
(both pigmented and nonpigmented layers)
4) Iris epithelium (posterior)
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
The invaginated neuroectoderm
gives rise to the:
1) Neurosensory retina
2) RPE
3) Ciliary-body epithelium (both pigmented
and nonpigmented layers)
4) Posterior epithelium of the iris
5) Pupillary sphincter muscle
6) Pupillary dilator muscle
Eye embryology made simply ridiculous
46

47. Eye embryology made simply ridiculous
47
Development of the lens is supported by the
tunica vasculosa lentis , a vascular web
surrounding the lens vesicle.
three Latin words

48. Eye embryology made simply ridiculous
48
Development of the lens is supported by the
tunica vasculosa lentis , a vascular web
surrounding the lens vesicle.

49. Eye embryology made simply ridiculous
49
Development of the lens is supported by the
tunica vasculosa lentis , a vascular web
surrounding the lens vesicle. The tunica
derives primarily from the hyaloid artery.

50. Eye embryology made simply ridiculous
50
Development of the lens is supported by the
tunica vasculosa lentis , a vascular web
surrounding the lens vesicle. The tunica
derives primarily from the hyaloid artery.

51. The pinched-off
sphere forms the
lens
vesicle
Eye embryology made simply ridiculous
51

52. The pinched-off
sphere forms the
lens
vesicle
Eye embryology made simply ridiculous
52

53. The pinched-off
sphere forms the
lens
vesicle
Eye embryology made simply ridiculous
53
Note that embryology explains why the lens is composed
of epithelial cells on the inside with their basement
membrane on the outside.

54. The pinched-off
sphere forms the
lens
vesicle
Eye embryology made simply ridiculous
54
Note that embryology explains why the lens is composed
of epithelial cells on the inside with their basement
membrane on the outside.
What structure of the adult lens derives from this basement membrane?
Your surgical nemesis—the lens capsule

55. The pinched-off
sphere forms the
lens
vesicle
Eye embryology made simply ridiculous
55
Note that embryology explains why the lens is composed
of epithelial cells on the inside with their basement
membrane on the outside.
What structure of the adult lens derives from this basement membrane?
Your surgical nemesis—the lens capsule

56. The pinched-off
sphere forms the
lens
vesicle
Eye embryology made simply ridiculous
56
(No question yet—advance when ready)
Soon the cells on the posterior aspect of the lens vesicle start to grow anteriorly,
eventually obliterating the lumen entirely. The structure thus formed is called the
embryonic nucleus

57. Embryonic
Nucleus
?
Eye embryology made simply ridiculous
57
Soon the cells on the posterior aspect of the lens vesicle start to grow anteriorly,
eventually obliterating the lumen entirely. The structure thus formed is called the
embryonic nucleus
two words

58. Embryonic
Nucleus
Eye embryology made simply ridiculous
58
Soon the cells on the posterior aspect of the lens vesicle start to grow anteriorly,
eventually obliterating the lumen entirely. The structure thus formed is called the
embryonic nucleus

59. Embryonic
Nucleus
Eye embryology made simply ridiculous
Fibers grow
from here
Fibers grow
from here
59
(No question yet—advance when ready)
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus

60. Embryonic
Nucleus
Eye embryology made simply ridiculous
Fibers meet and
interdigitate here
Fibers meet and interdigitate here
Fibers grow
from here
Fibers grow
from here
60
(No question yet—advance when ready)
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus

61. Embryonic
Nucleus
Eye embryology made simply ridiculous
61
Fetal
Nucleus
?
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus
two words

62. Embryonic
Nucleus
Eye embryology made simply ridiculous
62
Fetal
Nucleus
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus

63. Embryonic
Nucleus
Eye embryology made simply ridiculous
?
?
63
Fetal
Nucleus
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus
What two structures—easily observable in the adult lens—do these interdigitations form?
The Y sutures
What are the orientations of the two Y sutures?
The anterior Y suture is right-side up; the posterior Y suture is

64. Embryonic
Nucleus
Eye embryology made simply ridiculous
64
?
?
Fetal
Nucleus
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus
What two structures—easily observable in the adult lens—do these interdigitations form?
The Y sutures
What are the orientations of the two Y sutures?
The anterior Y suture is right-side up; the posterior Y suture is

65. Embryonic
Nucleus
Eye embryology made simply ridiculous
orY
Y
orY
Y
65
Fetal
Nucleus
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus
What two structures—easily observable in the adult lens—do these interdigitations form?
The Y sutures
What are the orientations of the two Y sutures?
The anterior Y suture is right-side up; the posterior Y suture is

66. Embryonic
Nucleus
Eye embryology made simply ridiculous
Fetal
Nucleus
Y
Y
66
The equatorial cells of the embryonic lens will then grow anteriorly and posteriorly,
insinuating themselves between the fetal fibers and the lens capsule. These fibers
meet and interdigitate at the anterior and posterior poles of the lens. This entire
structure is known as the fetal nucleus
What two structures—easily observable in the adult lens—do these interdigitations form?
The Y sutures
What are the orientations of the two Y sutures?
The anterior Y suture is right-side up; the posterior Y suture is
down
upside

67. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
one word
three words
67

68. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
68

69. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
69

70. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
70

71. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
71

72. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
72

73. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
What ocular structures derive from mesoderm? (mnemonic coming…)
--?
--?
--?
--?
73
The mnemonic is…

74. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
What ocular structures derive from mesoderm? (mnemonic coming…)
--M
--E
--S
--O
74
The mnemonic is…MESO

75. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
What ocular structures derive from mesoderm? (mnemonic coming…)
--M
--E
--S
--O
75
Start here

76. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
What ocular structures derive from mesoderm? (mnemonic coming…)
--Muscles (EOMs)
--E
--S
--O
76
Next

77. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
What ocular structures derive from mesoderm? (mnemonic coming…)
--Muscles (EOMs)
--Endothelium of the blood vessels
--S
--O
77
Next

78. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
What ocular structures derive from mesoderm? (mnemonic coming…)
--Muscles (EOMs)
--Endothelium of the blood vessels
--Schlemm’s canal
--O
78
Tricky one

79. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is mesoderm?
One of the three primary germ layers of the embryo
What are the other two primary germ layers?
--Ectoderm
--Endoderm
What ocular structures derive from mesoderm? (mnemonic coming…)
--Muscles (EOMs)
--Endothelium of the blood vessels
--Schlemm’s canal
--Oh, and don’t forget that small portion of the sclera!
79

80. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
80
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

81. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.
81

82. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--?
--?
--?
--?
--?
82
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

83. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--?
--?
--?
--?
83
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

84. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--?
--?
--?
--?
84
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

85. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
85
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.
angle structure (two words)

86. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
86
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

87. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--?
--?
87
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

88. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
88
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--?
--?

89. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
89
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.
Vascular tunic of eye

90. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
90
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

91. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera
91
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

92. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera
92
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

93. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
93
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

94. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
94
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

95. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave:
Third wave:
95
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

96. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave:
Third wave:
96
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

97. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave:
97
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

98. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave:
98
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

99. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
99
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo
and deposit themselves at a wide variety of locations, eventually differentiating
into a number of different tissues.

100. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
100

101. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
101

102. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
102

103. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
103
--?
--?
--?
--?
--?
--?
--?
--?

104. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
104
--Axenfeld-Reiger syndrome
--?
--?
--?
--?
--?
--?
--?
eponym-eponym

105. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
105
--Axenfeld-Reiger syndrome
--?
--?
--?
--?
--?
--?
--?

106. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
106
--Axenfeld-Reiger syndrome
--Peters anomaly
--?
--?
--?
--?
--?
--?
eponym

107. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
107
--Axenfeld-Reiger syndrome
--Peters anomaly
--?
--?
--?
--?
--?
--?

108. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
108
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--?
--?
--?
--?
--?
location

109. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
109
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--?
--?
--?
--?
--?

110. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
110
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--?
--?
--?
--?
location

111. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
111
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--?
--?
--?
--?

112. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
112
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--?
--?
--?
one K extreme the other

113. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
113
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--?
--?
--?

114. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
114
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--?
--?
(something)cornea shape

115. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
115
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--?
--?

116. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
116
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
two corneal
dystrophies

117. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
117
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD

118. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
What do CHED and CHSD stand for?
CHED: Congenital hereditary endothelial dystrophy
CHSD: Congenital hereditary stroma; dystrophy
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
What do CHED and CHSD stand for?
CHED: Congenital hereditary endothelial dystrophy
CHSD: Congenital hereditary stromal dystrophy
118

119. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
What do CHED and CHSD stand for?
CHED: Congenital hereditary endothelial dystrophy
CHSD: Congenital hereditary stroma; dystrophy
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
What do CHED and CHSD stand for?
CHED: Congenital hereditary endothelial dystrophy
CHSD: Congenital hereditary stromal dystrophy
119

120. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
Congenital glaucoma
(Just one, but it’s really important)
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
120
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD

121. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
Congenital glaucoma
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
121
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD

122. Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
Congenital glaucoma
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
122
Rule of thumb: Guess ‘neurocristopathy’ for any
condition involving anterior-segment dysgenesis—
chances are you will be correct!
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD

123. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
Congenital glaucoma
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
123
Finally, what major ocular structure have we yet to mention? What gives rise to it?
The vitreous. It derives from surface ectoderm, neuroectoderm, mesoderm—pretty much
everything BUT neural crest.
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD

124. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
Congenital glaucoma
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
124
Finally, what major ocular structure have we yet to mention? What gives rise to it?
The vitreous. It derives from surface ectoderm, neuroectoderm, mesoderm—pretty much
everything BUT neural crest.
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD

125. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
Congenital glaucoma
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
125
Finally, what major ocular structure have we yet to mention? What gives rise to it?
The vitreous. It derives from surface ectoderm, neuroectoderm, mesoderm—pretty much
everything BUT neural crest.
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD

126. What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--?
--?
--?
Eye embryology made simply ridiculous
In addition to surface- and neuroectoderm, there are two
embryologic cell/tissue types we must concern ourselves with:
Mesoderm
Neural crest cells
What is/are neural crest cells?
A special subpopulation of neuroectodermal cells that migrate across the embryo and
deposit themselves at a wide variety of locations, eventually differentiating into a number
of different tissues.
What ocular structures derive from neural crest cells?
Just about everything that has yet to be mentioned:
--Corneal stroma and endothelium
--Trabecular meshwork
--Iris stroma
--Choroid
--Most of the sclera (except the small part deriving from mesoderm)
What is a neurocristopathy?
A congenital/developmental abnormality owing to flawed neural-crest cell migration or differentiation
What are some examples of neurocristopathy?
Some of the important ones include…
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD
Congenital glaucoma
Neural crest cell migration concerning the anterior segment occurs in three ‘waves.’
Which wave involves which future structure?
First wave: Corneal endothelium
Second wave: Iris stroma
Third wave: Corneal stroma (keratocytes)
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Finally, what major ocular structure have we yet to mention? What gives rise to it?
The vitreous. It derives from surface ectoderm, neuroectoderm, mesoderm—pretty much
everything BUT neural crest.
--Axenfeld-Reiger syndrome
--Peters anomaly
--Posterior keratoconus
--Posterior embryotoxon
--Microcornea and megalocornea
--Sclerocornea and cornea plana
--CHED
--CHSD