gradual visual loss Flashcards
generalised reduction in visual acuity with starburst around lights
cataracts
peripheral loss of vision with halos around lights
glaucoma
central loss of vision with crooked or wavy appearance to straight lines
macular degeneration
what produces aqueous humour
ciliary body
normal intraocular pressure
10-21
pressure is created by resistance to flow through trabecular meshwork into canal of schlemm
what can cause cupping of the optic disc?
increased pressure
optic cup is made wider + deeper
optic cup > 0.5 the size of optic disc = abnormal
investigations for glaucoma
goldmann applanation tanometry = gold standard
–> makes contact with cornea, applies diff pressures
non-contact tanometry
–> puff of air, used in screening
fundoscopy = disc cupping
peripheral field assessment
open angled glaucoma
poor drainage of aqueous humour through trabecular meshwork, slow onset
RF = black, near-sightedness (myopia)
presentation of open angled glaucoma
peripheral vision first - eventually tunnel vision
gradual onset fluctuating pain
headaches
halos appearing around lights
optic disc cupping
criteria for beginning management of open angled glaucoma
pressure of 24 mmHG
pharma management of open angled glaucoma
1st line = prostaglandin analogue (latanoprost)
–> increase outflow
others reduce aqueous production
- timolol (BB)
- carbonic anhydrase inhibitor
closed angle glaucoma
when irisi bulges forward + seals off trabecular meshwork from anterior chamber preventing drainage
increased pressure pushes irish forward more + more
medical emergency
medications that can predispose close angle glucoma
adrenergic - noradrenalin
anticholinergic - oxybutynin, solifenacin
tricyclic antidepressants - amitriptyline
closed angle glucoma presentation
haxy cornea fixed pupil size blurred vision headache, N+V firm eyeball on palpation decreased visual acuity
initial management of closed angle glaucoma
pilocarpine - constrict pupils + contracts ciliary
–> opens pathway
acetazolamide - reduces production (carbonic anhydrase inhibitor)
definitive management of close angle glaucoma
laser iridotomy
–> zap hole in iris
papilloedema
bilateral dic swelling SECONDARY to raised intracranial pressure
(suspect space occupying lesion until proved otherwise)
causes of papilloedema
space occupying lesion
malignant hypertension - always check BP
idiopathic intracranial hypertension - young females
causes of increased cranial pressure
obstruction to CSF circulation - congenital malformation
overproduction of CSF - choroid plexus tumour
inadequate absorption - subarachnoid haemorrhage
endophthalmitis
inflammation of inner contents of eye
Mx = intravitreal antibiotics injected
classification of hypertensive retinopathy
Keith-Wagener
1 = mild narrowing
2 = focal constriction
3 = cotton wool, exudates, haemorrhages 4 = papillodema
hypertensive retinopathy presentation
cotton wool spots
atriovenous nipping - art compress veins where they cross
exudates
haemorrhages
papilloedmea - ischaemia to optic nerve resulting in optic nerve swelling + blurring of optic disc margins
types of macular degeneration
dry (90%) - gradual
wet (10%) - sudden, vascular proliferation
macular degeneration of funducopy
drusen = yellw deposits of protein + lipids
diagnosis of wet macular degeneration
optical coherence tomography
–> atrophy of retinal pigment epithelium, degeneration of photoreceptors
(shows cross section ofretina layers)
age related macular degeneration presentation
central vision loss - scotoma (blind spots/distortions)
wavy appearance to straight lines
(wet more acute - loss of vision over days)
fluorescein angiography
given fluorescin contrast + photgraph retina to look in detail at the blood supply to retina
–> shows any oedema + neovascularisation
(2nd line diagnosis for wet ARMD after OCT)
management of wet ARMD
anti-VGEF meds
ranibizumab, bavacizumab
injected directly into vitreous chamber once a month
slow + reverse progression
management of dry ARMD
lifestyle measures - smoking, bp, vitamin supplementation
social support
magnifiers
stages of diabetic retinopathy
- non proliferative
- proliferative
- diabetic maculopathy
diabetic retinopathy on fundoscopy
hard exudates microaneurysms blot haemorrhages neovascularisation cotton wool spots
what causes cotton wool spots
damage to nerve fibres
pathophysio of diabetic retinopathy
hyperglycaemia leads to damage to retinal small vessels + endthelial cells
damage to wall leads to microaneurysms, venous beading
increased vascular permeability leads to leakage - blot haemmorhages + hard exudates
management of diabetic retinopathy
yearly review
NP = observe, photocoag in severe
P = panretinal laser photpcoagulation, intravitreal VEGF inhibitors, vitereoretinal surgery in severe
maculopathy = intravitreal VEGF inhib if change in visual acuity
difference between proliferative and non-proliferative diabetic retinopathy
prolif = retinal neovascularisation - may lead to virous haemorrhage
–> patient may complain of floaters or sever visual loss
