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What populations have a high rate of myopia?
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What is considered low myopia?
-0.50 and -2.99
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What is considered moderate myopia?
-3.00 and -5.99D
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What is considered high myopia?
>-6.00D and axial length >26mm
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Age of onset of myopia?
childhood- teenage
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adult onset myopia?
- 10-50% of myopia manifests during adulthood
- low-moderate
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When is high myopia most commonly seen?
childhood onset
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What are 3 myopia associated ocular changes?
- myopic maculopathy/retinopahty and chorioretinal changes
- PPCA
- posterior staphyloma
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What are the main features of myopic maculopathy?
- 1. tessellated fundus & geographic atrophy
- 2. CNV beneath macula
- 3. Fuch's spot
- 4. Coin haem with lacquer cracks
- 5. Macular holes/retinoschesis
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What are lacquer cracks and what does it look like?
- large breaks in RPE- bruch's membrane
- irregular fine yellow lines across posterior pole
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Do the lacquer cracks occur before or after CNV/geographic atrophy?
before
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What are some ddx for lacquer cracks?
- Angloid streaks: radiate from disc, straighter, reddish in colour- idiopathic
- Choroidal ruptures: ASSOC TRAUMA,
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What might be the cause of haemorrhages close to the macula?
CNV are very leaky
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What is fuch's spot?
- occurs after old haemorrhage
- follows from resorption of haem, 2ndy proliferation of RPE
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What is ddx of geographic atrophy at the macula?
dry amd
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Other ddx of maculopathy, chorioretinal degeneration and atrophy?
- 1. choriodaemia
- 2. Gyrate atrophy
- 3. Diffuse choroidal atrophy
- 4. Progressive bilateral chorioretinal atrophy
- 5. AMD
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How can you differentiate bw macula hole and chorioretinal atrophy?
choroid will still be visible beneath
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What is the cause behind a tilted disc related to myopia?
- failure of supporting tissues to shape direction of nerve fibres in pre/retro laminar of optic nerve
- oblique insertion
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What is the most common form of tilted disc related to high myopia?
inferior dysversion
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What are some key features of TDS?
- bilateral
- inferonasal conus
- situs inversus vessels
- D disc shape
- myopic astig
- thinning of inferonasal choroid/rpe
- Raised superotemporal OD- displaces inferonasal vessels
- VF defects- superotemporal- however do not respect the vertical midline
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Difference in VF results of Congenital TDS and bitemporal hemianopia?
TDS is confined to superotemporal and doesn't respect the vertical midline
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Lattice degeneration?
- looks like vascular white line changes due to thinning of RPE
- sclerosis of vessels-> walls hardened unable to supply blood-> ischaemia
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What is a staphyloma?
protrustion of sclera ususally lined with uveal tissue
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What are some assoc of high myopia to other ocular conditions?
- rhegmatogenous RD
- PVD
- lattice degeneration
- atrophic/macula holes
- giant retinal tears
- cataracts
- glaucoma
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Myopia and cataracts?
- PSC, nuclear sclerosis
- O2 therapy+ vitrectomy increase risk of catarcts
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Myopia and glaucoma?
increase in glaucoma with higher axial length
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What are some systemic associations linked with high myopia?
- marfans
- ehler-danlos
- sticklers
- albinism
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How to manage high myopia?
- CL
- orthoK
- scleral crosslinking?
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