19. Pathological Myopia

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19. Pathological Myopia
2013-11-13 07:32:53
Pathological Myopia

Pathological Myopia
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  1. What populations have a high rate of myopia?
    • singapore
    • taiwan
    • HK
    • >80%
  2. What is considered low myopia?
    -0.50 and -2.99
  3. What is considered moderate myopia?
    -3.00 and -5.99D
  4. What is considered high myopia?
    >-6.00D and axial length >26mm
  5. Age of onset of myopia?
    childhood- teenage
  6. adult onset myopia?
    • 10-50% of myopia manifests during adulthood
    • low-moderate
  7. When is high myopia most commonly seen?
    childhood onset
  8. What are 3 myopia associated ocular changes?
    • myopic maculopathy/retinopahty and chorioretinal changes
    • PPCA
    • posterior staphyloma
  9. 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
  10. What are lacquer cracks and what does it look like?
    • large breaks in RPE- bruch's membrane
    • irregular fine yellow lines across posterior pole
  11. Do the lacquer cracks occur before or after CNV/geographic atrophy?
  12. What are some ddx for lacquer cracks?
    • Angloid streaks: radiate from disc, straighter, reddish in colour- idiopathic
    • Choroidal ruptures: ASSOC TRAUMA,
  13. What might be the cause of haemorrhages close to the macula?
    CNV are very leaky
  14. What is fuch's spot?
    • occurs after old haemorrhage
    • follows from resorption of haem, 2ndy proliferation of RPE
  15. What is ddx of geographic atrophy at the macula?
    dry amd
  16. Other ddx of maculopathy, chorioretinal degeneration and atrophy?
    • 1. choriodaemia
    • 2. Gyrate atrophy
    • 3. Diffuse choroidal atrophy
    • 4. Progressive bilateral chorioretinal atrophy
    • 5. AMD
  17. How can you differentiate bw macula hole and chorioretinal atrophy?
    choroid will still be visible beneath
  18. 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
  19. What is the most common form of tilted disc related to high myopia?
    inferior dysversion
  20. 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
  21. Difference in VF results of Congenital TDS and bitemporal hemianopia?
    TDS is confined to superotemporal and doesn't respect the vertical midline
  22. Lattice degeneration?
    • looks like vascular white line changes due to thinning of RPE
    • sclerosis of vessels-> walls hardened unable to supply blood-> ischaemia
  23. What is a staphyloma?
    protrustion of sclera ususally lined with uveal tissue
  24. What are some assoc of high myopia to other ocular conditions?
    • rhegmatogenous RD
    • PVD
    • lattice degeneration
    • atrophic/macula holes
    • giant retinal tears
    • cataracts
    • glaucoma
  25. Myopia and cataracts?
    • PSC, nuclear sclerosis
    • O2 therapy+ vitrectomy increase risk of catarcts
  26. Myopia and glaucoma?
    increase in glaucoma with higher axial length
  27. What are some systemic associations linked with high myopia?
    • marfans
    • ehler-danlos
    • sticklers
    • albinism
  28. How to manage high myopia?
    • CL
    • orthoK
    • scleral crosslinking?