This document provides information about myopia (nearsightedness), including its definition, causes, types, classifications, signs and symptoms, and treatment options. It discusses the different mechanisms that can cause myopia, including excessive axial length growth. It classifies myopia based on clinical features, degree, and age of onset. Treatment options covered include optical correction with glasses or contact lenses, as well as surgical procedures like LASIK, PRK, phakic IOL implantation, and corneal ring segments.
Aphakia and its causes. Correction of Aphakia. Advantages and disadvantages of different corrections. Surgeries and related signs and symptoms of aphakia. Complications related to Aphakia.
When parallel rays of light enter the eye ((with accommodation relaxed) and do) and do not come to a single point focus on or near the retina.
Types of Astigmatism:
Sign & Symptoms:
Management:
TONOMETRY • Tonometry is the procedure performed to determine the intraocular pressure (IOP).
3. CLASSIFICATION TONOMETRY DIRECT INDIRECT Indentation Applanation Manometer
4. APPLANATION Contact Non-contact Goldmann Perkins Air-puff Pulse air
5. INDENTATION TONOMETER • It is based on fundamental fact that plunger will indent a soft eye more than hard eye. • The indentation tonometer in current use is that of Schiotz . • It was devised in 1905 and continued to refine it through 1927.
6. PROCEDURE • Patient should be anaesthetising with 4% lignocaine or 0.5% proparacaine. • with the patient in supine position, looking up at a fixation target while examiners separates the lids and lower the tonometer plate to rest on the cornea so that plunger is free to move. •
Aphakia and its causes. Correction of Aphakia. Advantages and disadvantages of different corrections. Surgeries and related signs and symptoms of aphakia. Complications related to Aphakia.
When parallel rays of light enter the eye ((with accommodation relaxed) and do) and do not come to a single point focus on or near the retina.
Types of Astigmatism:
Sign & Symptoms:
Management:
TONOMETRY • Tonometry is the procedure performed to determine the intraocular pressure (IOP).
3. CLASSIFICATION TONOMETRY DIRECT INDIRECT Indentation Applanation Manometer
4. APPLANATION Contact Non-contact Goldmann Perkins Air-puff Pulse air
5. INDENTATION TONOMETER • It is based on fundamental fact that plunger will indent a soft eye more than hard eye. • The indentation tonometer in current use is that of Schiotz . • It was devised in 1905 and continued to refine it through 1927.
6. PROCEDURE • Patient should be anaesthetising with 4% lignocaine or 0.5% proparacaine. • with the patient in supine position, looking up at a fixation target while examiners separates the lids and lower the tonometer plate to rest on the cornea so that plunger is free to move. •
www.ophthalclass.blogspot.com has the complete class and MCQs on lids and adnexa for undergraduate medical students. Class 1 in the series deals with the basic anatomy of the eyelid and the eyelid margin. A few of the congenital eyelid disorders are mentioned. Special emphasis is given to blepharitis – inflammation of the eyelid margin, its types, clinical features and management. Next, common causes of eyelid swellings including hordeolum or stye and chalazion are discussed. Finally a brief mention is made about disorders of the eyelashes – trichiasis, poliosis, madarosis and distichiasis.
The lecture concern the eyelids and contain the following subjects and medical terms:
* Anatomy
* Congenital ptosis
* blepharophimosis
* *Epicanthus
* Ptosis syndrome
* amblyopia (Lazy eye)
* Strabismus and its types(Hypertropia, Hypotropia, Esotropia, Exotropia )
* The Fasanella-Servat procedure(video) for correcting upper ptosis
* levator resection(video) another procedure for correting ptosis
* Acquired ptosis and its ptosis
Nearsightedness (myopia) is a common vision condition in which near objects appear clear, but objects farther away look blurry. It occurs when the shape of the eye — or the shape of certain parts of the eye — causes light rays to bend (refract) inaccurately. Light rays that should be focused on nerve tissues at the back of the eye (retina) are focused in front of the retina.
Nearsightedness usually develops during childhood and adolescence, and it usually becomes more stable between the ages of 20 and 40. Myopia tends to run in families.
A basic eye exam can confirm nearsightedness. You can compensate for the blurry vision with eyeglasses, contact lenses or refractive surgery.
A refractory error is a very common eye disorder. It occurs when the eye cannot clearly focus the images from the outside world. The result of refractory errors is blurred vision ,which is sometimes so severe that it causes visual impairment.
complete information about the refractive errors due to the problem in the acomodation of eye lense , disturbed image formation in the retina, contains -types of disease condition .
MYOPIA , basics , causes , types and treatmentssuserde6356
Myopia, also known as near-sightedness and short-sightedness, is an eye disease[5][6][7] where light from distant objects focuses in front of, instead of on, the retina.[1][2][6] As a result, distant objects appear blurry while close objects appear normal.[1] Other symptoms may include headaches and eye strain.[1][8] Severe myopia is associated with an increased risk of macular degeneration, retinal detachment, cataracts, and glaucoma.[2][9]
Myopia results from the length of the eyeball growing too long or less commonly the lens being too strong.[1][10] It is a type of refractive error.[1] Diagnosis is by the use of cycloplegics during eye examination.[11]
Tentative evidence indicates that the risk of myopia can be decreased by having young children spend more time outside.[12][13] This decrease in risk may be related to natural light exposure.[14] Myopia can be corrected with eyeglasses, contact lenses, or by refractive surgery.[1][15] Eyeglasses are the simplest and safest method of correction.[1] Contact lenses can provide a relatively wider corrected field of vision, but are associated with an increased risk of infection.[1][16] Refractive surgeries like LASIK and PRK permanently change the shape of the cornea. Surgeries like Implantable Collamer Lens (ICL) implant a lens inside the anterior chamber in front of the natural eye lens. ICL doesn't affect the cornea.[
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Best Ayurvedic medicine for Gas and IndigestionSwastikAyurveda
Here is the updated list of Top Best Ayurvedic medicine for Gas and Indigestion and those are Gas-O-Go Syp for Dyspepsia | Lavizyme Syrup for Acidity | Yumzyme Hepatoprotective Capsules etc
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Adv. biopharm. APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMSAkankshaAshtankar
MIP 201T & MPH 202T
ADVANCED BIOPHARMACEUTICS & PHARMACOKINETICS : UNIT 5
APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMS By - AKANKSHA ASHTANKAR
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
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CDSCO and Phamacovigilance {Regulatory body in India}NEHA GUPTA
The Central Drugs Standard Control Organization (CDSCO) is India's national regulatory body for pharmaceuticals and medical devices. Operating under the Directorate General of Health Services, Ministry of Health & Family Welfare, Government of India, the CDSCO is responsible for approving new drugs, conducting clinical trials, setting standards for drugs, controlling the quality of imported drugs, and coordinating the activities of State Drug Control Organizations by providing expert advice.
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In India, pharmacovigilance activities are monitored by the Pharmacovigilance Programme of India (PvPI), which works closely with CDSCO to collect, analyze, and act upon data regarding adverse drug reactions (ADRs). Together, they play a critical role in ensuring that the benefits of drugs outweigh their risks, maintaining high standards of patient safety, and promoting the rational use of medicines.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
3. MYOPIA
• Short sightedness
• Myopia is a greek word meaning *close
the eye*
• Refractive error I
• Parallel rays of light coming from
infinity are focused in front of the
retina.
• Accommodation is at rest
3
4. Mechanism of production
• Axial
• Curvatural
• Positional
• Index
• Myopia due to excessive accommodation
4
5. Optics of myopia
• Far point is finite (In front of the eye)
• Emmetropic eye it is at infinity
• Higher the myopia the shorter the distance
• Far point is 1mt from the eye ,there is 1D of
myopia
• Nodal point is further away from retina
Accommodation need not develop
normally resulting in
Convergence insufficiency
Exophoria
5
6. TYPES OF
CLASSIFICATION
• Clinical
Classification
• Degree of Myopia
• Age of Onset
6
8. Degree of Myopia
• Low Myopia(<3D)
• Medium
Myopia(3-6D)
• High Myopia(>6D)
8
9. AGE OF ONSET
• Congenital Myopia
• Youth-Onset
Myopia(<20 yrs of age)
• Early Adult-Onset
Myopia(20-40 yrs of
age)
• Late Adult-Onset
Myopia(>40 yrs of age)
9
10. Congenital myopia
Frequently seen in
Premature babies
Marfan’s syndrome
Homocystinuria
Increase in axial length
Increase inOverall globe size
Since birth, diagnosed at age 2-3 years
If unilateral, as anisometropia, may develop
amblyopia, strabismus
Usually 8-10 D, remain constant
Bilateral- difficulty in distant vision, hold
10
things very close
11. Associated conditions
Convergent squint
Cataract
Microphthalmos
Aniridia
Megalocornea
Congenital Separation of retina
Management
Early Correction is desirable
Retinoscopy under full cycloplegia
Early full correction desirable
Poor prognosis
11
12. • Simple / developmental myopia
Physiological error not associated with any
disease of the eye
Etiology :
Normal biological variation in development of
eye
Inheritence
12
14. Clinical picture
Rarely present at birth
Rather born hypermetropic, become myopic
Begins at 7-10 years, stabilizing around mid
teens
Usually around 5D, never exceeds 8D
14
15. Symptoms
Poor vision for distance
Asthenopic symptoms develop due to
dissociation between accommodation and
convergence
Convergence weakness, exophoria,
suppression
Excessive accommodation inducing ciliary
spasm and artificially increasing the amount
of myopia
Psychological outlook 15
16. Signs
Large and prominent
Deep AC
Large, sluggishly reacting pupils
Normal fundus, rarely crescent
Usually doesn't exceed 6-8D
• Retinoscopy under full cycloplegia
16
17. • Pathological / degenerative /
progressive myopia
Rapidly progressive associated with
degenerative changes in the eye
Etiology
Rapid axial growth of the eyeball outside the
normal biological variations of development
Role of heredity
Role of general growth process
17
18. Genetic factors General growth
process
More growth of retina
Stretching of sclera
Increased axial length
Degeneration of choroid
Degeneration of retina
18
20. Signs
EYE Large, prominent eyes simulating
exophthalmos
CORNEA large
ANTERIOR CHAMBER deep
LENS show opacities at the posterior pole
due to aberration of lenticular metabolism
and due to overstretching anterior
dislocation may also occur
20
21. VITEROUS degeneration,viterous
liquefication,vitreous detachment present
as WEISS REFLEX
SCLERA thinning resulting in formation of
STAPHYLOMA
VISUAL FIELD DEFECTS show Contraction
and in some ring scotomas present
21
22. DISC
Large in size
Myopic Crescent on the temporal side of the
disc
Choroidal Crescent
Supertraction of the retina
Inverse myopia Myopic crescent situated
nasally and supertraction of the retina
temporally
called as INVERSE CRESCENT
Peripapillary Atrophy
22
28. Guidelines
LOW DEGREES OF MYOPIA (Up to -6D)
IN YOUNG SUBJECTS
Defect should never be overcorrected and advised for
constant use to avoid squinting and develop a normal
ACCOMMODATION-CONVERGENCE reflex
IN ADULTS
Receiving spectacle for the first time,have the ciliary
muscle that are unaccostomed to accommodate
efficiently so that lens of slightly lower power(1 or 2 D)
may be prescribed for reading,especially if engaged in to
any greater extent.Above the age of 40 years,when
accommodation fails physiologically, a weaker glass for
28
near work is essential
29. HIGH DEGREES OF MYOPIA
Full correction rarely be tolerated so we attempt to
reduce the correction as little as is compatible with
comfort for binocular vision. We prescribe the lens
with which the greatest visual acuity is obtained
without distress
29
31. ADVANTAGES OF SPECTACLES
Economical
Allow incorporation of prism,bifocals,pal
which can be used for the management
of esophoria or any accommodative
disorders accompanying myopia
Spectacles require less accommodation
than contact lens for myopia that
likelihood of accommodative asthenopia
or near point blur in patients
approaching presbyopia may be less
31
32. DISPENSING SPECTACLES IN HIGH
MYOPIA
• High index lens materials
• Lighter lens materials
• Reduced eyesize of selected frames
• Minus lenticular lens designs
32
33. ADVANTAGES OF CONTACT LENS
• Contact lens provides cosmosis
• Large retinal image size and slightly better visual
acuity in severe myopia
33
35. Photorefractive
Keratectomy
(PRK)
• Involves direct laser ablation of corneal
stroma after removal of corneal epithelium
mechanically or using a laser beam.
• Done using Excimer laser
• MUNNERLYN EQN: depth of ablation
(micrometer)=[diameter of optical
zone(mm)]² × 1/3power(Diopter)
• For myopic a large amount of ablation is
done in central cornea than in the
periphery.
• Give good results for -2D to -6D of myopia 35
36. LASIK
Laser Assisted In situ
Keratomileusis
• Method:Anterior flap of cornea is lifted with a keratome and
excimer laser is used to sculpt the stromal bed to change the
refractive error of eye
• Corrects 0.5 to 12D of myopia and upto 8D of astigmatism
• Guidelines:Age more than 18yrs
BCVA better than 6/12
Stable refraction for last 1yr
Absence of corneal disease & ectasia
• Note:
• (1) In no case the residual bed thickness after the ablation
should measure 250microns so as to avoid central corneal
ectasia
• (2) Ideally the ablation should be done within 30sec of the
preparation of flap
36
38. • Method:
• Simple inexpensive procedure that
involves creation of epithelial flap after
exposure to 18% alcohol for 25sec &
subsequent replacement of flap after
laser ablation
38
39. RK
Radial Keratotomy
• It refers to making deep corneal incisions(initially
16,now down to 4) in the peripheral part of cornea
leaving about 4mm central optical zone
• The incisions are made almost down to the level of
Descemet’s Membrane
• These incisions on healing flatten the central
cornea thereby reducing its refractive power
• For low to moderate degree of myopia(-1.5 to
-6D of myopia)
39
40. Epikeratophakia
• For high degree of myopia (upto 20D)
• Method:
• The epithelium is removed & then a
pocket is fashioned under the edge
of the remaining epithelium & into
this is inserted the cryolathed donor
homograft
• Preserved material can also be used
40
41. NON CORNEAL
INTERVENTIONS
• (A) REMOVAL OF CLEAR LENS
• We know that an aphakic eye is strongly
hypermetropic
• If an eye with an axial myopia of -24D is deprived
of its lens it will become emmetropic without any
correcting lens
• Note:
• Whenever surgery on clear lens is contemplated
the eye is examined thoroughly for abnormalties
like Raised IOP,Vitreous & retinal degeneration
etc
41
42. • (b)Phakic intraocular lenses
• An IOL of appropriate power is implanted
inside the eye without touching normal
crystalline lens thus without disturbing
accomodation
• Method can be used to correct both myopia &
hypermetropia
• Phakic IOL types:
• PC IOL
• Angle supported IOL
• Iris claw lens
42
43. INTRA CORNEAL
RING(ICR)
IMPLANTATION
• ICR implantation into the peripheral
cornea approx.upto 2/3rd of stromal
depth can also be considered for
correction of myopia
• It results in a vaulting effect that
flattens the central cornea
decreasing the myopia
• The procedure has the advantage of
being reversible 43
44. For Further Queries Contact :
Ms. Priyanka Singh
Head – Optometry Service
Email – optometry@venueyeinstitute.org
44