B2. Retinal Degeneration & Dystrophy Flashcards
prevalence of stargardt’s disease? what is it characterised by?
also called juvenile macular dystrophy
most common macular dystrophy
Common cause of central vision loss in adults < 50
Characterised by accumulation of lipofusin within RPE
Presentation typically in childhood or adolescence
prognosis for stargardt’s disease? what VA will it stabilize at?
Prognosis is poor, and once VA drops below 6/12 it tends to worsen rapidly before stabilizing at 6/60
5 SSx of stargardt’s disease?
Symptoms:
1. Gradual impairment of central vision
- May have complaints of reduced colour vision and impairment of dark adaptation
Signs:
3. the macula may be normal initially and then show nonspecific mottling
- progression to geographic atrophy or bull’s-eye maculopathy
- yellow-white lesions at the level of the RPE (accumulation of lipofusin)
Mx for stargardt’s disease?
No treatment
Low vision aids if vision is poor (visually impaired)
Genetic counselling
Avoid Vitamin A supplement as it may accelerate lipofusin accumulation
prevalence of bests disease? what is it characterised by? hint: what gene?
Second most common macular dystrophy, after Stargardt disease
inheritance is AD (BEST1 gene),
Bestrophin (BEST1) is found on the plasma membrane of RPE and functions as a transmembrane ion channel
SSx of best’s disease? ( early mid and end stage)
Early: vitelliform appearance develops in early childhood with a round, sharply delineated (‘sunny side up’) macular lesion
mid: slow progression to ‘vitelliruptive’ stage (mass ruptures into subretinal space), gradual fall in VA
End-stage: macular atrophy.
Mx for stargardt’s disease?
No treatment
Low vision aids if vision is poor (visually impaired)
Genetic counselling
what are the 5 stages of best’s disease? SVPVA
stage 1 (subclinical):
often do not carry macular alterations; a thickened ellipsoid zone can be observed on spectral-domain optical coherence tomography (SD-OCT).
stage 2 (vitelliform):
typically show a yellow egg yolk–like macular lesion; this lipofuscin material appears as a discrete, subretinal hyperreflective deposit on SD-OCT.
stage 3 (pseudo-hypopyon):
disclose a clear altitudinal rearrangement of the vitelliform material; SD-OCT confirms reabsorption of the material and the appearance of subretinal fluid.
stage 4 (vitelliruptive):
are characterized by a remarkable disruption of the vitelliform lesion; the resulting SD-OCT scan reveals an inhomogeneous hyperreflective material, with scant subretinal fluid.
stage 5 (atrophic) show clear signs of macular atrophy; loss of the outer nuclear layers and retinal pigment epithelium is evident on SD-OCT.
what is retinitis pigmentosa? what photoreceptors does it affect?
A group of inherited diffuse retinal degenerative disease
Initially predominantly affecting the rod photoreceptors, with later degeneration of cones (rod-cone dystrophy)
prevalence of RP? how is it caused genetically
Most common hereditary fundus dystrophy, prevalence 1:5000
It can be sporadic or inherited as AD, AR, or X-L; many cases are due to mutation in the rhodopsin gene.
what are the 2 stages of RP? SSx of each stage?
early stage:
night vision problems
progressive peripheral vision restriction
late stage:
tunnel vision at later stage of the disease
4 signs of RP?
1. RPE atrophy associated with arteriolar narrowing
2. “bone-spicule” pigmentary changes at periphery
- Waxy pallor of optic disc
- gradual increase in density and extent of the pigmentary change
4 potential complications of RP?
- Posterior subscapsular cataract
2, Open-angle glaucoma (3%) - Keratoconus (uncommon)
- Posterior vitreous detachment
