Myopia
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Transcript of Myopia
![Page 1: Myopia](https://reader036.fdocuments.in/reader036/viewer/2022070303/548f81e8b479590c798b497f/html5/thumbnails/1.jpg)
MYOPIASaad Bin Zafar Mahmood
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Emmetropia
24-25mm
43 diopters
18 diopters
Accomodation at rest
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A form of refractive error in which parallel rays of light entering the eye are focused in front of retina with accomodation being at rest
Myopia - Defination
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Curvature
Axial length
Refractive index
Positional
Etiology
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Congenital
Simple
Degenerative
Types of myopia
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Unilateral / Bilateral
Stationary
Associated with convergent squint
Congenital myopia
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Most common refractive error
Age of onset
Moderate severity
No degenerative changes
Simple myopia
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Progressive in nature
Age of onset
Severe
Hereditary in nature
Degenerative myopia
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Pathogenesis
Degenerative changes in sclera
Increase in axial length of eyeball
Elongation and stretching of sclera
Changes in choroid and retina
DECREASE VISION
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Myopic Crescent
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Lacquer CracksBreaks in Bruch’s membrane
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Sub retinal neovascularization
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Sub retinal hemorrhage
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Foster – Fuch’s spots
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Posterior staphyloma
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Macular hemorrhage
Posterior staphyloma
Retinal detachment
Glaucoma
Complications
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Distant blurred vision
Half shutting of eyes
Divergent squint
Clinical features - Symptoms
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Prominent eyeballs
Anterior chamber is deep
Ultrasongraphy
Fundus examination
Signs
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Concave lenses◦ Children◦ Adults
Contact lenses
Medical treatment
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Cornea
For high refractive errors
◦ Clear Lens extraction
◦ Phakic posterior chamber implant
Surgical treatment
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Radial Keratotomy
◦ Radius of the curvature of cornea is reduced (flattened)
◦ Series of radial incisions in peripheral cornea
◦ Can correct upto 4 diopters
◦ Less popular these days due to PRK and LASIK
Cornea
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Photorefractive keratectomy
◦ Laser procedure
◦ Central corneal surface is ablated
◦ Results in flattening of cornea
◦ A 10um ablation corrects a 1 dipotre of myopia
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LASIK (Laser in-situ keratomileusis)
Step 1
Step 2
Step 4
Step 3
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Absence of post-operative pain
Less haze
Rapid recovery
Advantages of LASIK
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Hybrid of PRK and LASIK
It involves separation of epithelium
Difference with LASIK is the thickness of epithelium
LASEK (Laser epithelial keratomileusis)
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