macular degeneration Flashcards
what is it?
Degeneration of the central retina (macula)
what is age related MD characterised by?
degeneration of retinal photoreceptors that results in the formation of drusen which can be seen on fundoscopy and retinal photography
what are RF for MD?
advancing age
smoking
FH
ischaemic cardiovascular disease such as hypertension, dyslipidaemia and diabetes mellitus.
what are the 2 types?
wet and dry
what is dry macular degeneration?
90% of cases
also known as atrophic
characterised by drusen - yellow round spots in Bruch’s membrane
what is wet macular degeneration?
also known as exudative or neovascular macular degeneration
characterised by choroidal neovascularisation
leakage of serous fluid and blood can subsequently result in a rapid loss of vision
which has the worst prognosis?
wet MD carries the worst prognosis
how is MD classified by age?
early age-related macular degeneration (non-exudative, age-related maculopathy): drusen and alterations to the retinal pigment epithelium (RPE)
late age-related macular degeneration (neovascularisation, exudative)
what are the features?
a reduction in visual acuity, particularly for near field objects
difficulties in dark adaptation with an overall deterioration in vision at night
fluctuations in visual disturbance which may vary significantly from day to day
they may also suffer from photopsia, (a perception of flickering or flashing lights), and glare around objects
visual hallucinations may also occur resulting in Charles-Bonnet syndrome
what is the onset of visual loss in the different types?
gradual in dry ARMD
subacute in wet ARMD
what are the signs of MD?
distortion of line perception may be noted on Amsler grid testing
fundoscopy reveals the presence of drusen, yellow areas of pigment deposition in the macular area, which may become confluent in late disease to form a macular scar.
in wet ARMD well demarcated red patches may be seen which represent intra-retinal or sub-retinal fluid leakage or haemorrhage.
what ix are done?
slit-lamp microscopy (initial)
fluorescein angiography is utilised if neovascular ARMD is suspected
optical coherence tomography is used to visualise the retina in three dimensions
how is it treated?
DRY - zinc with anti-oxidant vitamins A,C and E
WET - vascular endothelial growth factor (VEGF)
laser photocoagulation does slow progression of ARMD where there is new vessel formation
