B3 Age Related Macular Degeneration Flashcards
define AMD (ssx)
it is a condition affecting the macula
prior to AMD occurring… the RPE usually will undergo hypoxia with aging. signs will present as drusen, and in more severe cases: choroidal neovascularisation (CNV), pigmented epithelial detachment (PED)
symptoms: impairment of central vision, metamorphopsia (tested with amsler grid, straight lines appear wavy), poor colour vision, delayed photo stress recovery, positive central scotoma, micropsia/macropsia
define & explain drusen
it is the buildup of lipofuscin between the RPE and bruch’s membrane. this is caused by dysfunction of choriocapillaries and hence, RPE and outer retina undergoes ischemia. as a result, there is incomplete breakdown of PR outer segments (recall waste is produced during). hence the build up of lipofuscin
[lipofuscin: aging pigments, waste products of RPE]
drusen pushes RPE cells upward into the photoreceptors
and hence present as “RPE window effect” -> well defined, circular areas of RPE atrophy
explain 2 types of drusen
hard: in earlier AMD, associated with RPE dysfunction (aging), presents as small/discrete-round-yellowwhite spots, located on top of bruch’s membrane
soft: later stages of AMD, associated with ischemia & hence may lead to CNV, presents as larger-pale yellow-indistinct margins (*cotton wool spots), located nearer to RPE
state who is at risk of AMD
leading cause of irreversible blindness in developed world in those over age 50
age > 50, caucasians, poor diet, family history, smokers, obesity, poorly controlled HTN & HCL, UV overexposure
state 2 types of AMD
dry (non-exudative/atrophic) & wet (exudative)
explain dry/non-exudative AMD (ssx)
90% of AMD cases, early stages of AMD
signs: focal RPE depigmentation, well defined & circular areas of RPE atrophy with PR loss(soft/hard drusens), enlargement of atrophic areas aka geographic atrophy
symptoms: GRADUAL loss of central vision, central scotoma, NO METAMORPHOPIA, bilateral but severity asymmetric
explain management of dry AMD
EARLY referral if metamorphopsia observed
educate px of potential progression to wet AMD
provide amsler chart for them to self check daily
advise good lighting
lifestyle change: quit smoking, intake green leafy vegetables / antioxidant supplements, exercise regularly, maintain normal BP / cholesterol
follow up every 3-6 months
explain wet/exudative AMD (ssx)
10-20% of individuals progress to wet AMD after dry AMD. it is the presence of CNV
signs: presence of CNV -> growth of neovascular membrane due to foveal hypoxia & leaky BVs may cause serious/exudative retinal detachment
[opthalmoscopy views: grey/green haemorrhages/exudates under RPE, macular oedema, pigmentation, PED, disciform scar (-> vision loss in that area)]
symptoms: metamorphopsia, rapid loss of vision (<6/60), central vision loss -> “cannot see faces”
explain management of wet AMD
URGENT referral
treatment: photodynamic therapy (medication injected collects abnormal BVs and lasering to stop BV growth) or anti-VEGF (vascular endothelium growth factor) ie. Avastin/lucentis within 72 hours
laser photocoagulation can reduce CNV progressing, reducing risk of severe vision loss
