Ophthalmology Flashcards
What are 4 signs on examination of uveitis?
- ciliary (circumcorneal) injection
- aqueous flare - leakage of protein + leukocytes into anterior chamber
- keratic precipitates - on posterior surface of cornea
- posterior synechiae
What is Talbot’s test?
pain on pupil constriction when tested with convergence - moving finger closer to eyes
What is the commonest cause of orbital cellulitis in children and why?
Ethmoidal sinusitis - relatively thin medial wall of the orbit
What are 5 risk factors for orbital cellulitis?
- childhood - mean age of hospitalisation 7-12 years
- previous sinus infection
- lack of haemophilus influenzae type b (Hib) vaccination
- recent eyelid infection / insect bite on eyelid (periorbital celllulitis)
- ear or facial infection
What are 4 things that differentiate orbital from preseptal cellulitis?
- reduced VA
- propotosis
- ophthalmoplegia / pain with eye movements
- RAPD
How much does family history increase the risk of age-related macular degeneration?
first degree relatives 4x more likely to inherit
What is the normal optic disc to cup ratio?
0.4 - 0.7
What are 6 risk factors for age-related macular degeneration?
- advancing age, particularly >75y
- smoking
- family history
- factors increasing risk of ischaemic heart disease - hypertension, dyslipidaemia, diabetes mellitus
- female gender
What proportion of cases of AMD are dry?
90%
What investigations are indicated for wet AMD and why?
fluorescein angiography (+- indocyanine green angiography to visualise choroidal circulation) - can guide intervention with anti-VEGF therapy
What treatment option is there for dry AMD?
zinc and anti-oxidant vitamins A + C + E (best in patients with extensive drusen, at least moderate category)
What is the treatment of a corneal abrasion?
topical chloramphenicol to prevent infection
What are 2 options for treatment of wet ARMD and what is the drawback of the less preferred option?
- anti VEGF e.g. ranibizumab, bevacizumab, pegaptanib
- laser photocoagulation - risk of acute visual loss after treatment (especially sub-foveal ARMD)
What are the criteria for someone to be registered as severely sight impaired?
Visual acuity <3/60 with full visual field wearing glasses as prescribed - in better eye
How can you distinguish between causes of Horner’s syndrome clinically?
- central: anhidrosis down one side of face, arm and trunk
- preganglionic: anhidrosis of face
- postganglionic: no anhidrosis
What characterises mild/moderate/severe non-proliferative retinopathy?
- mild: 1 or more micro aneurysm
- moderate: microaneurysms, blot haemorrhages, hard exudates, cotton wool spots, venous beading, IRMA
- severe: blot haemorrhages and microaneurysms in 4 quadrants, venous beading in at least 2 quadrants, IRMA in at least 1 quadrant
What characterises diabetic maculopathy?
Hard exudates and other background changes on macula
In which diabetes type is maculopathy more commonly seen?
T2DM
In which diabetes type is proliferative retinopathy more commonly seen?
T1DM
What are the treatment options for diabetic:
- maculopathy
- non-proliferative retinopathy
- proliferative retinopathy
- anti-VEGF
- PRP if severe
- anti-VEGF, PRP, vitreoretinal surgery
What are 2 complications of PRP?
- reduction in peripheral vision
- poor night vision (more rods in peripheral retina)
Why is diabetes a risk factor for developing cataract? Give the 3 explanations
- increased intracellular accumulation of sorbitol (from glucose metabolism) leads to hyperosmotic effect, resulting in hydropic lens fibres that degenerate and form cataract
- osmotic stress due to swelling of cortical lens fibres (esp T1DM)
- autoimmune hypothesis in bilateral T1DM cataracts
What are the 2 commonest aetiologies for rubeosis iridis?
- central retinal venous occlusion
- diabetic retinopathy
What type of glaucoma can develop due to rubeosis iridis?
initially secondary open angle glaucoma - vessels impair aqueous humour outflow; can progress to secondary closed angle glaucoma as fibrotic membranes develop and contract