age related macular degeneration + cataracts Flashcards
what is ARMD
degeneration of the macula which causes a progressive deterioration in vision
UK most common cause of bindness
ARMD on fundoscopy
drusen - yellow deposits of protein and lipids between the retinal pigment epithelium and brush’s memrbane
atrophy of retinal pigemtn epithelium
degeneration of photoreceptors
what is the macular?
it is made of four layers
1) choroid layer - blood vessels (bottom)
2) Bruch’s membrane
3) retinal pigment epithelium
4) photoreceptors
risk factors for ARMD
Age Smoking White or Chinese ethnic origin Family history Cardiovascular disease
ARMD on fundoscopy
drusen - yellow deposits of protein and lipids between the retinal pigment epithelium and brush’s memrbane
atrophy of retinal pigemtn epithelium
degeneration of photoreceptors
ARMD signs and symptoms
Gradual worsening central visual field loss
Reduced visual acuity
Crooked or wavy appearance to straight lines
two types of ARMD
wet- development of new vessels from the choroid layer to the retina. the vessels leak fluid / blood which caues oedema and more rapid vision loss (VEGF stimulates new vessel develompent) worse prognosis and more acute, and bilateral.
dry-
examination for ARMD
Reduced acuity using a Snellen chart
Scotoma (a central patch of vision loss)
Amsler grid test can be used to assess the distortion of straight lines
Fundoscopy. Drusen are the key finding.
imaging for ARMD
Slit-lamp biomicroscopic fundus examination by a specialist can be used to diagnose AMD.
Optical coherence tomography is a technique used to gain a cross-sectional view of the layers of the retina. It can be used to diagnose wet AMD.
Fluorescein angiography involves giving a fluorescein contrast and photographing the retina to look in detail at the blood supply to the retina. It is useful to show up any oedema and neovascularisation. It is used second line to diagnose wet AMD if optical coherence tomography does not exclude wet AMD.
management for ARMD
wet- anti VEGF meds ranibizumab, bevacizumab, pegaptanib block VEGF which slows development of new vessels. they are injected into viterous chamber once a month
dry- no specific management. lifestyle measures to slow progression. stop smoking, control BP, vitamin supplementation (C and E) (beta carotene and zinc)
what is cataracts?
lens in the eye becomes cloudy and opaque which reduces vsual acuity by reducing the light that enters the eye
lens focuses light onto the retina and is held by suspensory ligaments which are attached to the cilary body
ciliary body contraction = releases tension on suspensory ligaments= lens thickens
ciliary body relax= increases tension on the suspensory ligaments= lens narrows
lens is usually nourished by surroundign fluid (does not have its own blood supply)
how does cataracts develop?
most is over advanced age + risk factors (Increasing age, smoking, alcohol, diabetes, steroids, hypocalcaemia)
can get congenital cataracts *red reflex in neonatal exam
how might cataracts present?
asymmetrical
very slow reduction in vision (visual acuity)
progressive blurring of vision
change of colour of vision (more brown/yellow)
starburst round lights (night time)
loss of red reflex (grey/white)
management of catraracts
cataract surgery- artificial lens
complication of cataract surgery
endopthalmitis
rare but serious complication
inflammation of the inner content of hte eye caused by infection. treat with intraviteral abx
