Ophthalmology Flashcards
List the differentials for painless red eye
Episcleritis
Subconjunctival haemorrhage
conjunctivitis
List differential causes of a painful red eye
Acute angle closure glaucoma Anterior Uveitis Scleritis Keratitis Corneal ulcers/abrasions Foreign body Trauma Chemical injury
Describe cataract and it’s risk factors
Opacification and clouding of the lens (which is avascular)
Older age Congenital (TORCH infections) Smoking Alcohol (dehydration) Iatrogenic -> steroids, vitrectomy, IV injections
What are the S/S of cataract?
Change in colour vision (becomes more brown/yellow)
Vision worse at night -> glare and starbursts around lights
Myopic shift (become short sighted i.e. cannot see things far away)
Protein aggregation and lens opacification
Reduced VA
Loss of red reflex
Define phakic, aphakic and pseudophakic
Phakic = natural lens
Aphakic - eye has no lens
Pseudophakic - lens has been artificially replaced
What is the treatment for cataracts?
Conservative - do nothing if not severe
Phacoemulsification (uses USS) to emulsify lens and then replace with new one
Describe complications of cataract surgery
Endophthalmitis = inflammation of inner eye, 3-5 days post op, needs treated with intravitreal antibiotics
Retinal detachment
Acute angle closure glaucoma (cataract proteins can leak into the anterior chamber)
Define glaucoma
Group of eye diseases resulting in damage to the optic nerve, often due to increased IOP
Describe the production and flow of aqueous humour in the eye
Produced by the ciliary body, flows from the posterior chamber around the iris to the anterior chamber, drains through trabecular meshwork (through Canal of Schlemm) into general circulation
Describe the classifications of glaucoma and describe the pathophys behind each
Open or closed angle
Acure or chronic
Primary or secondary
Open = there is resistance to flow of aqueous humour through the trabecular network
Closed = Iris pushed forwards against the cornea and blocks flow of aqueous humour into the trabecular mesh
What are the risk factors for acute angle closure glaucoma?
Age Hypermetropia (long-sighted and having a smaller eye) FHx East Asian/Chinese Shallow anterior chamber
What are the risk factors for open angle glaucoma?
Age Black Myopic (short-sighted i.e. bigger eye) Smoking Diabetes HTN
What is the classical S/Sx of glaucoma?
How is glaucoma investigated?
Halos around lights at night
Peripheral vision affected
Increased cup:disc ratio >0.5
(Goldmann applanation) tonometry = measuring pressure
Fundoscopy - assess for disc cupping
Visual fields
How is open angle vs closed angle glaucoma treated?
Open angle:
- prostaglandins (latanoprost) to increase outflow of fluid
- beta blocker (timolol) to reduce fluid production
- carbonic anhydrase (dorzolamide) - reduce aqueous humour production
- Sympathomimetics (brimonidine) - increase outflow and reduce fluid production
(surgical = trabeculectomy)
Closed angle:
- pilocarpine (muscarinic receptor agonist which constrict pupil to open up the pathway for aqueous humour to flow)
- acetazolamide 500mg oral (carbonic anhydrase inhibitor) to reduce fluid production
- then same drugs as open ^^^
(surgical: Iridotomy, trabeculectomy)
Describe AMD and its subtypes
Age related macular degeneration
Progressive degenerative disease involving macula
Dry (atrophic) or wet (exudative - caused by choroidal neovascularisation)
Dry = 90%, Wet = 10%
What are the presenting features of macular degeneration?
Describe pathophysiology
Reduced VA
Central vision lost / metamorphopsia
Normal peripheral vision
Pathophysiology:
- Disruption of Bruch’s layer and RPE cells
What are the risk factors for AMD?
Smoking Increasing age HTN CVD FH Female Hypermetropia Caucasian
What are the fundoscopy findings in wet vs dry AMD?
Dry: macula drusen, RPE hyperpigmentation
Wet: haemorrhages, lipid exudates, neovascularisation…
How is AMD investigated?
What is the treatment for AMD?
VA
Fundoscopy (look for drusen vs neovascularisation)
Amsler chart (look for metamorphopsia)
Fluoroscein angiogram - to show neovascularisation
Dry - no treatment (reduce RFx e.g. stop smoking)
Wet - Intravitreal injections (Anti-VEGF)
Differentiate scleritis and episcleritis
Episclera = between conjunctiva and sclera
Sclera = the white outer coating of the eye (under the episclera)
Episcleritis = mild pain and self-limiting, blanches with phenylephrine
Scleritis = acute red eye, pain on movement and keeps awake at night, associated with RA and GPA, does not blanch with phenylephrine
What is Charles Bonnet syndrome?
Where visual hallucinations occur as a result of visual loss
Not related to psychosis/dementia
The patient is very aware that their hallucinations are not real
What are the S/Sx of acute angle closure glaucoma
Sudden onset painful red eye Blurry vision Photophobia Headache Halos around lights N&V
Hazy cornea (oedema) Mid-dilated fixed pupil Iris bombe Reduced VA Closed angle on gonioscopy
Describe endophthalmitis and how it may present
Infection of the aqueous +/- vitreous humour which causes inflammation in the eye
Most commonly occurs post-op from cataract surgery
Onset 1-7 days post-surgery Disproportionate/increasing post-operative inflammation Hypopyon Pain Worsening vision Posterior segment inflammation RAPD Lid swelling
Define central retinal artery occlusion and its risk factors
= blockage of the retinal artery which carried oxygen to the nerve fibres in the retina RFx: - HTN - ageing - glaucoma - DM
How is CRAO caused?
Atherosclerosis
Suggestive if: HTN, diabetes, hypercholesterolaemia, smoking
Embolism: Carotid artery disease, valvular disease
Inflammatory: GCA
Medications: OCP, cocaine
Sickle cell disease
What are the clinical features of CRAO?
Sudden onset, unilateral, PAINLESS vision loss White swollen retina with a ‘cherry red spot’ RAPD Visible emboli (25%)
