Ophthalmology Flashcards
Acute angle-closure glaucoma
Risk factors:
- hypermetropia (long sight)
- pupillary dilatation
- lens growth with age
Features:
- severe pain & decreased visual acuiity
- symptoms with with mydriasis
- hard, red eye
- haloes around lights
- semi-dilated, non-reacting pupil
- corneal oedema = hazy cornea
- systemci upset
Investigation:
- tonometry for elevated IOP
- gonoiscopy
Mx:
- urgent referral to ophthalmology
- combination eyedrops:
- pilocarpine: contraction of the ciliary muscle → opening the trabecular meshwork → increased outflow of the aqueous humour
- timolol: decrease aqueous humour production
- alpha-2-agonist: decrease aqueous humour production and increasing uveoscleral outflow
- IV acetylzolamide: reduce aqueous secretions
Definitive Mx: laser peripheral iridotomy:
- creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle
Age-related macular degeneration
Risks: age, smoking, FH, HTN, DM
Dry macular degeneration: drusen in Bruchs membrane (90% of cases)
Wet: choroidal neovascularisation
Features:
- reduced visual acuity, gradual in dry ARMD, subacute in wet ARMD
- glare around objects
- visual hallucinations
Signs:
- distortion of lines on amsler grid
- fundscopsy: drusen
Investigations:
- slit lamp
- fluorescein angiography if neovascularisation suspected
- OCT for 3D visualisation
Management:
- Dry: zinc + antioxidant vitamins A, C and E
- anti-VEGF agents e.g. ranibizumab, bevacizumab and pegaptanib
- laser photocoagulation slows progression inc neovasc
Anterior uveitis
Association with HLA-B27
Features:
- RED EYE
- pain
- blurred vision
- impaired visual acuity
- hypopyon (fluid in the anterior chamber)
Associations: ank spond, reactive arthritis, UC, CD, behcets, sarcoid
Management
- urgent ophthalm review
- cycloplegics (DILATE pupil) - atropine
- steroid eye drops
Blepharitis
Inflammation of the eyelid margins
Sx:
- bilateral
- grittiness, discomfort
- eyelids sticky
- styes and chalazions
- secondary conjunctivitis
Mx:
- hot compress
- lid hygiene
- artificial tears if dry eyes or abnormal tear film
Central retinal artery occlusion
Features:
- sudden painless loss of vision
- RAPD
- cherry red spot on pale retina
Mx: difficult & poor prognosis
- underlying conditions treated
- thrombolysis
Diabetic retinopathy
Non-proliferative:
- mild: 1+ microaneurysm
- moderate: microaneurysm, blot haemorrhages, hard exudates, cotton wool spots
- severe: blot haemorrhage & micros in 4 quadrans, venous beading in 2, IRMA in 1
Proliferative:
- retinal neovascularisation
- most common in type 1 DM
Maculopathy:
- hard exudates & other ‘background’ changes in macula
- more common in type II
Management
- optimise glycaemia control
- maculopathy: VEGF inhibitors
- non-prolif: reg observation, if severe panretinal laser
- proliferative: panretinal laser photocoagulation* and intravitreal VEGF inhibitors
*A decrease in night vision is a potential complication of panretinal photocoagulation
Herpes simplex keratitis
Features:
- red, painful eye
- photophobia
- epiphora
- visual acuity may be decreased
- fluorescein staining may show an epithelial ulcer
Mx:
- immediate ophthalmologist referral
- topical aciclovir
Keratitis
Causes:
- bacterial: staph aureus or pseudomonas aerginosa in contact lens wearers
- fungal
- amoebic (acanthamoebic keratitis) in contaminated water
- parasitic: onchocercal keratitis (‘river blindness’)
Features: red eye, pain, photophobia, foreign body, gritty sensation, hypoyon
Referral:
contact lens wearers presenting with red eye - same-day referral to an eye specialist is usually required to rule out microbial keratitis
Mx:
- stop using contact lens until the symptoms have fully resolved
- topical antibiotics: typically quinolones are used first-line
- cycloplegic for pain relief
e.g. cyclopentolate
Optic neuritis
Causes: MS, diabetes, syphillis
Sx:
- unilateral decrease in visual acuity
- red desaturation
- pain worse on eye movement
- RAPD
- central scotoma
Invesitgation: MRI with gadolinium contrast
Mx:
- high dose steroids (4-6w recovery)
Primary open angle glaucoma
Risk: age, genetics, myopia, HTN, DM, corticosteroids
Fundoscopy:
1. optic disc cupping >0.7 (normal = 0.4-0.7)
2. optic disc pallor - optic atrophy
3. bayonetting of vessels
Investigation
- tonometry to measure IOP
- central corneal thickness measurement
- gonioscopy to assess peripheral anterior chamber configuration and depth
Mx:
1. offer 360° selective laser trabeculoplasty (SLT) first-line to people with an IOP of ≥ 24 mmHg
2. prostaglandin analogue eye drops (lantoprost) - increase outflow (brown pigmentation of iris)
3. beta blockers (e.g. timolol) - reduce production of aqueous fluid (avoid in asthmatics and heart block)
4. carbonic anhydrase inhibitor eye drops e.g. dorzolamide - reduces aqueous production
5. sympathomimetics (e.g. brimonidine, an alpha2-adrenoceptor agonist) - reduces aqueous production and increases outflow
6. surgery
Retinal detachment
Risks - diabetes, myopia, age, cataract surgery, trauma e.g. boxing
Sx:
- floaters or flashes
- progressive vision loss
- RAPD
- red reflex lost
Mx: any patients with new onset flashes and floaters should be referred urgently (<24 hours) to an ophthalmologist for assessment with a slit lamp and indirect ophthalmoscopy for pigment cells and vitreous haemorrhage
Visual field defects
Left homonymous hemianopia means visual field defect to the left, i.e. Lesion of right optic tract
Homonymous quadrantanopias: PITS (Parietal-Inferior, Temporal-Superior)
Incongruous defects = optic tract lesion; congruous defects = optic radiation lesion or occipital cortex
Homonymous hemianopia:
- incongruous defects: lesion of optic tract
- congruous defects: lesion of optic radiation or occipital cortex
- macula sparing: lesion of occipital cortex
Homonymous quadrantanopias:
- superior: lesion of the inferior optic radiations in the temporal lobe (Meyer’s loop)
- inferior: lesion of the superior optic radiations in the parietal lobe
- mnemonic = PITS (Parietal-Inferior, Temporal-Superior)
Bitemporal hemianopia:
- lesion of optic chiasm
- upper quadrant defect > lower quadrant defect = inferior chiasmal compression, commonly a pituitary tumour
- lower quadrant defect > upper quadrant defect = superior chiasmal compression, commonly a craniopharyngioma
Orbital cellulitis
Risk factors - child, sinus infection, lack of Hib vaccine, periorbital cellulitis, ear or facial infection
Sx - redness/swelling, occular pain, visual disturbance, pain on eye movement, drowsiness +/- nausea/vomiting
Orbital vs pre-septal
- reduced visual acuity, proptosis, ophthalmoplegia/pain with eye movements are NOT consistent with preseptal cellulitis
Investigations:
- FBC: WCC elevated and inflam markers
- decreased vision, RAPD, proptosis, dysmotility, oedema, erythema
- CT with contrast: Inflammation of the orbital tissues deep to the septum, sinusitis.
- Blood culture and microbiological swab to determine the organism. Most common bacterial causes – Streptococcus, Staphylococcus aureus, Haemophilus influenzae B.
Mx:
- admit for IV ABX
