This document defines refractive errors and discusses their causes, types, and management. Refractive errors occur when the shape of the eye prevents light from properly focusing on the retina, causing blurred vision. The main types are myopia, hyperopia, astigmatism, and presbyopia. Myopia is near-sightedness caused by the eyeball being too long, while hyperopia is far-sightedness caused by the eyeball being too short. Astigmatism results from an irregularly shaped cornea. Presbyopia is age-related and due to stiffening of the lens. Management involves correcting refractive errors with appropriate eyeglasses or contact lenses, or refractive surgery in some cases. Eye exams are

1. TOPIC: REFRACTIVE ERRORS
BY
LT. EDWIN NIWAGABA
+256776233241, +252612487284
EYE DEPT. LEVEL II FIELD HOSPITAL

2. OUT LINE
 Back ground
 Definition
 Anatomy of the eye
 Optics
 Causes
 Types
 Management
 Appreciating Eye wear.

3. Back Ground
 314 million people are visually impaired from all
causes.
 Refractive errors (RE) account for 153 million
people.
 80% of the causes are preventable.
 90% of the world’s visually impaired live in
developing countries

4. Cont..
 RE increase risk of death, physical, social and
emotional problems in people over 50 years.
 Focus on international effort to combat avoidable
blindness.-in line with "VISION 2020 -- The
Right to Sight“.

5. Definition.
 RE - occur when the shape of the eye prevents light
from focusing directly on the retina resulting in a
blurred image.
 The length of the eyeball (longer or shorter),
changes in the shape of the cornea, or aging of the
lens can cause refractive errors.

6. Cont.
 Refraction is the bending of light as it passes
through one object to another.
 Light rays are refracted at the cornea & lens,
focused on the retina which converts light-rays into
messages through the optic nerve to the brain.
 The brain interprets these messages.

7. Anatomy

8. Eye ball

9. Optics

10. Astigmatism

11. MYOPIA (nearsightedness)
 Refractive system too convergent.
 Axial A-P axis of eye is too long
 DM hyperglycaemia leads to swelling of lens
 Image formed in front of retina
S/S
 Blurr vision-Far worse than near
 Eye strain
 Head ache
 Learning difficuilities
 RX-concave lens

12. HYPEROPIA (farsightedness)
 Image formed behind retina
 Refractive system too divergent
 A-P axial too short
S/S
 Blurr vision-near worse than far
 Eye strain
 Head ache
 Learning difficuilty
 RX-convex lens.

13. ASTIGAMATISM
 Irregular curveture of cornea;different projection
points in vertical and horizontal meridians,distorted
images on retina.
S/S
 Blurr vision,
 Eye strain,
 Head ache,
 Fatigue,
 Fearning difficuilt.
 RX- A cylindrical lens.

14. Presbyopia
 Loss of elasticity of lens/ciliary muscles
(accommodation).
 Age-related-age 40 years
 Genetic.
S/S
 Difficuilty reading small script,cutting
nails,Knitting,sorting rice from stones,etc
 RX-convex lens

15. Effects of RE
 Hamper performance at school.
 Reduce employability and productivity at work
 Impair quality of life.
 Correction of refractive errors with appropriate
spectacles.

16. Mx: Visual Acuity (VA)

17. Mx: VA assessment

18. VA-Distance

19. VA -near distance

20. Objective Refraction

21. Auto refractor and Retinoscope

22. RX
 No eye medicines
 Eye glasses
 Contact Lenses.
 Refractive Surgery- on Corneal shape /lens
 Microsurgery - lens implants/ laser treatment to the
cornea.

23. Optical dispensing
Single vision??

24. Optical dispensing

25. Life style

26. Glasses
Plastic Glass
ADVANTAGES
Light,
Durable
cheap
DISADVANTAGES
Expensive Heavy,
Easily break

27. Face shapes

28. Flame

29. Job specific Eye wear.
 Computer Glasses
 Safety Glasses
 Sport Safety
 Glasses
 Driving Glasses
 Swim Goggles
 Sunglasses

30. SUMMERY
 Define the refractive errors.
 Types of refaractive Errors
 Myopia,hyperopia,Astigmatsm,presbyopia
 Mx:-spectacles. Glasses/Plastic,
 Single vision,bifocal,progressive.
Clear,photogray?
 Optical needs should collide with
style,class,smartness.

31. END
 QUESTION