2 - vision loss Flashcards
what is arterial supply to retina?
internal carotid gives off ophthalmic artery which gives off branches central retinal artery & posterior ciliary arteries
what are the causes of sudden vision loss? (7)
- CRAO (central retinal artery occlusion)
- CRVO (central retinal vein occlusion)
- ischaemic optic neuropathy (optic nerve occlusion)
- haemorrhage (either neovascularisation or normal blood vessels)
- retinal detachment
- wet ARMD (age related macular degeneration)
- glaucoma - closed angle
what are symptoms & appearance of eye in central retinal artery occlusion?
symptoms = painless sudden loss of vision
signs = pale retina with thread like vessels. cherry red spot (fovea)
*will have positive RAPD - swinging light defect
what are causes CRAO?
- carotid artery disease (atherosclerotic plaque)
- emboli from heart-unusual
- giant cell arteritis
what is amaurosis fugax?
amaurosis = darkening. fugax = fleeting - fleeting darkness = transient vision loss (like curtain coming down, lasting a few minutes then going back to normal)
*you refer to stroke clinic as often warning of something bad happening
what causes central retinal vein occlusion?
artery lying on top of vein, artery becomes athersclerotic making artery rigid structure and squashing the fragile veins
what are symptoms and signs on eye of central retinal vein occlusion?
symptom = painless sudden vision loss
signs = dark red retina with haemorrhages & dilated/torturous vessels. also disc swelling & macular swelling
what is ischaemic optic neuropathy?
when posterior ciliary arteries that supply optic nerve occluded causing sudden painless vision loss and swollen optic nerve (looks pale & swollen)
*giant cell arteritis can cause
what are vitreous haemorrhages?
either from neovascularisation abnormal blood vessels from diabetes (like when ischaemia in diabetes body tries to compensate by making more vessels but the new ones are weak & rupture = haemorrhage)
- or from tear of normal blood vessels
what are symptoms & signs on eye of vitreous haemorrhage?
symptoms = sudden vision loss & floaters (brown specs)
signs = loss of red reflex & might see neovascularisations if that’s the cause
what is wet age related macular degeneration?
it’s the more aggressive & sudden vision loss causing
- it’s when new blood vessels grow under retina, leakage causes build up of fluid then scarring
what are symptoms of wet age related macular degeneration? treatment?
- rapid central vision loss
- maybe distortion before complete loss (called metamorphopsia)
anti-VEGF treatment (as VEGF is what stimulates new growths under retina)
what is end result of all glaucoma types?
end result of all types glaucoma = damage to optic nerve
what is normal humour production vs what happens in closed angle glaucoma?
so usually aqueous humour made in ciliary processes (in posterior chamber) then it flows out of pupil to into anterior chamber supplying cornea then reabsorbed by veins
- in closed angle iris bulges forward sealing off trabecular meshwork from anterior chamber preventing aqueous humour leaving pupil so humour builds up increasing intraocular pressure
what are symptoms & signs of eye in closed angle glaucoma?
symptoms = very painful sudden vision loss, so painful get sore head & nauseating pain w vomiting
signs = red eye, cloudy cornea, mid dilated pupil, eye feels hard on palpation
how do you treat closed angle glaucoma?
- acute presentation lower IOP with pilocarpine 4% drops
- definitive treatment = laser iridotomy (small hole in peripheral iris to drain fluid, relieving pressure)
what are causes of gradual vision loss? (5)
- cataract
- dry ARMD
- refractive error
- open angle glaucoma
- diabetic retinopathy/maculopathy
what is a cataract? causes?
cloudiness of lens from abnormal changes to lens proteins making structural change of proteins so loss transparency
*lots causes e.g. age, congenital, diabetes, steroids, trauma
what are symptoms of cataracts?
- gradual blurring of vision
- glare
- loss of red reflex
how do you treat cataracts?
surgical removal w intraocular lens implant (if patient symptomatic)
what is dry ARMD?
- dry age related macular degeneration is gradual & less aggressive loss of vision due to drusen (lipid by product) build up that over time stops retina working properly & causing thinning
what are symptoms & signs on eye of dry ARMD?
symptoms = gradual loss of vision, central vision missing (scotoma) - since macula
signs = drusen build up, atrophic patch of retina (retinal cells die off)
what is treatment of dry ARMD?
= no cure just supportive treatment like referring to visual impairment surfaces for social help etc and also magnifiers (which increase size of retinal image - scotoma remains same size but image bigger so less blocked by scotoma)
= vitamins (zinc & antixocidants)
what is refractive error? types? treatment)
when eye can’t focus on image, treat with glasses
myopia = short sighted (can’t see far)
hypermetropia = long sighted (can’t see close)
astigmatism = irregular corneal curve making blurred vision
presbyopia = can’t see close but due to ageing specifically
what is open angle glaucoma?
it’s not totally understood but thought to be high intraocular pressure risk factor (can be from connective tissue blocking trabecular meshwork so aqueous humour stuck increasing IOP)
*idk just know high intraocular pressure risk factor & open angle is gradual vision loss
what are symptoms & signs of open angle glaucoma?
symptoms = often none since gradual, brain sort if compensates
signs = maybe high IOP, cupped disc (large cup = glaucoma), visual field defect
*cupped disc has like thinned outside e.g. thinned inferior rim = superior field loss
what is optic neuritis?
inflammation of optic nerve - usually due to multiple sclerosis (in young adults)
what is presentation of optic neuritis?
- unilateral vision loss
- eye pain worse on movement
- dyschromatopsia (impaired colour vision)
- central scotoma
= positive RAPD
what is investigations & management of optic neuritis?
investigate = MRI brain & lumbar puncture (since assoc with MS)
manage = IV methylprednisolone, 4-6 wk recovery
what is treatment of open angle glaucoma?
1st line = latanoprost (prostaglandin agonist)
2nd line = beta blockers or carbonic anhydrase (acetazolamide)
what is emmetropia?
no refractive error = light focussed onto retina as normal
what is ametropia?
refractive error present - light focussed in front of retina or behind retina
what is anisometropia?
significant difference between R&L ametropia (refractive power)
what is management of squint (strabismus)?
- glasses or surgery
- also if small children then cover good eye with patch for a few hours a day to help brain process signals from both eyes
what is
a) esotropia
b) exotropia
c) hypertropia
d) hypotropia
a) inward movement of eye
b) outward movement of eye
c) upward movement of eye
d) downward movement of eye
