Minimal Ophthalmology Flashcards
Which blood test is warranted where a cataract is found?
Blood glucose to exclude diabetes mellitus
Symptoms associated with cataracts:
Blurred vision Loss of stereopsis (distance judgement) Loss of vision- bilateral ± dazzle in sunlight ± monocular diplopia
Indications for cataract surgery:
Troubling symptoms
Restricted lifestyle as a result
Unable to read a number plate at 67 feet for driving
Post-op complications of cataract surgery?
Capsule thickening- Yag laser capsulotomy corrects
Astigmatism becomes more noticable
Eye irritation, anterior uveitis
Rarely: vitreous haemorrhage, endophthalmitis, retinal detachment
Typical causes of gradual vision loss:
Cataract (bilateral)
Macular degeneration- damage to retinal pigment epithelium
Open angle glaucoma- optic neuropathy + abnormal cup:disc
Diabetic retinopathy
Hypertension retinopathy
Optic atrophy- pale discs in MS or in external nerve pressure
Difference between wet and dry macular degeneration:
Dry- pigment, drusen (cellular debris between retinal nerve layer and choroid blood vessels), degeneration of the macula
Wet- new vessels grow from choroid blood vessel layer into the retinal nerve layer and may cause fluid exudation, localised detachment or leakage
What is optic atrophy and what causes it?
Pale discs, due to death of retinal ganglion cell axons, end stage point of a number of diseases:
Raised intraocular pressure- glaucoma
Retinal damage- post uveitis or retinitis pigmentosa
Ischaemia- retinal artery occlusion
Multiple sclerosis
External pressure on nerve- intraorbital or cranial tumours, paget’s
Which eye disease presents with gradual loss of vision in teenagers with prominent yellow flecks on the retina?
Stargardt macular degeneration
Rx options for age-related macular degeneration:
Use optical coherence tomography + retinal photograph for reviewing
Conservative- Antioxidant, vitamin supplements, green leafy diet, visual aids
Medical- Intravitreal VEGF inhibitors: reduces blood vessel formation
Intravitreal steroids
Interventional- Laser photocoagulation: destroys hypoxic nerve source of VEGF
How is glaucoma defined?
Field testing: 3 or more locations outside normal limits
Cup-to-disc ratio: enlarged
Often associated with raised intraocular pressure, although not necessarily, due to clogged drainage canals (trabecular meshwork)
Signs on fundoscopy of glaucoma:
Optic disc cupping enlargement of the cup asymmetry of the cup, >0.6-0.7 cup to disc ratio disappearing vessels running along the cup disc pales
Rx for open angle glaucoma:
Reduce intraocular pressure: Alpha R agonists- SE vasodilation B blocker- timolol to reduce aqueous production Carbonic anhydrase inhibitors Prostaglandin analogue Pilocarpine- activates cholinergics
Surgery: trabeculectomy creates a bleb- reservoir
Features of hypertensive retinopathy:
Shiny wiring
Cotton wool spots (ischaemia from narrowed arterioles)
Flame haemorrhages
Leaks from vessels- hard exudates
What structural changes occur in diabetic eye disease?
Accelerated cataract formation
Neovascularisation on iris which may block fluid drainage= glaucoma ensues
Features + stages of diabetic retinopathy
Non-proliferative: blot + flame haemorrhages, dot microaneurysms hard exudates of oedema, cotton wool ischaemic spots, (severe) engorged tortuous veins (severe) venous changes- beading, loops
Proliferative: neo-vascularisation
Maculopathy: leakage of vessels causing oedema
Sudden loss of vision, 5 questions to ask to rule out imminent things?
Headache? GCA- check ESR
Eye movements hurt? Optic neuritis
Lights prior to visual loss? Detached retina
Like a curtain descending? Amaurosis fugax- emboli
Poorly controlled DM? Vitreous. Haemorrhage
Causes of sudden painless loss of vision?
Anterior ischaemic optic neuropathy: posterior ciliary arteries blocked by atheroma or inflammation (GCA) which supply optic nerve
Central retinal artery occlusion: which supplies the retina- often thromboembolic
Retinal vein occlusion
Vitreous haemorrhage
Optic neuritis- associated with MS, eye movements hurt
Retinal detachment
Causes of transient visual loss:
Vascular, TIA
Migraine, optic neuritis
Pappiloedema
Management of vitreous haemorrhage?
May cause loss of red reflex
B scan US can identify cause
If dense, vitrectomy can be performed
May need to treat vessel formation with anti-VEGF, photocoagulation
Rx of optic neuritis?
Pain on eye movements, unilateral visual loss, red desaturation
High dose methylprednisolone
Associated with MS, diabetes, syphilis, vitamin deficiency etc
Cause of sudden bilateral visual loss?
Rare- could be CMV infection in HIV patients
4 F’s of how retinal detachment present?
Flashes
Floaters (can occur in vessel leakage)
Fall in acuity
Field loss
Cause of acute closed angle glaucoma?
Blocked flow of aqueous from the anterior chamber via the canal of Schlemm
Presents with: painful red eye, headache, nausea, blurred vision or haloes around light
Fixed mid-dilated pupil, cloudy cornea, corneal injection
Blurred at ischaemia prevents Na-K-ATPase pump of endothelium of cornea removing water leading to clouding of cornea
Management of glaucoma?
Pilocarpine (cholinergic agonist) constricts eye to open up angle at canal of Schlemm
IV acetazolamide- reduce aqueous
B blocker, prostaglandin analogue, alpha agonists = adjuncts
Surgical: Peripheral iridectomy once intraocular pressure is controlled
Features of anterior uveitis:
Pain, photophobia
Reduced acuity
No sticky discharge- unlike conjunctivitis, but lacrimation (tears)
Ciliary congestion
Small pupil or irregular (synechiae)
Hypopyon
Talbot’s test +ve: pain increases on convergence
Management of acute anterior uveitis?
Steroid eyedrops to reduce inflammation
Cyclopentolate to keep pupil dilated and prevent adhesions
What is associated with anterior uveitis, scleritis and episcleritis?
Ant uveitis (A UV:
Ank spond
UC/Crohns
Virus- HIV, herpes
Scleritis: SLE, vasculitis, RA
Episcleritis: SLE, vasculitis
How do cataracts differ if they are caused by steroid use compared to old age?
Steroids- subcapsular, deep to the lens capsule
Age- nuclear, in the centre of the lens
