19. Pathological Myopia
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19. Pathological Myopia
What populations have a high rate of myopia?
What is considered low myopia?
-0.50 and -2.99
What is considered moderate myopia?
-3.00 and -5.99D
What is considered high myopia?
>-6.00D and axial length >26mm
Age of onset of myopia?
adult onset myopia?
10-50% of myopia manifests during adulthood
When is high myopia most commonly seen?
What are 3 myopia associated ocular changes?
myopic maculopathy/retinopahty and chorioretinal changes
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
What are lacquer cracks and what does it look like?
large breaks in RPE- bruch's membrane
irregular fine yellow lines across posterior pole
Do the lacquer cracks occur before or after CNV/geographic atrophy?
What are some ddx for lacquer cracks?
: radiate from disc, straighter, reddish in colour- idiopathic
: ASSOC TRAUMA,
What might be the cause of haemorrhages close to the macula?
CNV are very leaky
What is fuch's spot?
occurs after old haemorrhage
follows from resorption of haem, 2ndy proliferation of RPE
What is ddx of geographic atrophy at the macula?
Other ddx of maculopathy, chorioretinal degeneration and atrophy?
2. Gyrate atrophy
3. Diffuse choroidal atrophy
4. Progressive bilateral chorioretinal atrophy
How can you differentiate bw macula hole and chorioretinal atrophy?
choroid will still be visible beneath
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
What is the most common form of tilted disc related to high myopia?
What are some key features of TDS?
situs inversus vessels
D disc shape
thinning of inferonasal choroid/rpe
Raised superotemporal OD- displaces inferonasal vessels
VF defects- superotemporal- however do not respect the vertical midline
Difference in VF results of Congenital TDS and bitemporal hemianopia?
TDS is confined to superotemporal and doesn't respect the vertical midline
looks like vascular white line changes due to thinning of RPE
sclerosis of vessels-> walls hardened unable to supply blood-> ischaemia
What is a staphyloma?
protrustion of sclera ususally lined with uveal tissue
What are some assoc of high myopia to other ocular conditions?
giant retinal tears
Myopia and cataracts?
PSC, nuclear sclerosis
O2 therapy+ vitrectomy increase risk of catarcts
Myopia and glaucoma?
increase in glaucoma with higher axial length
What are some systemic associations linked with high myopia?
How to manage high myopia?