Ophthalmology Flashcards
Painful visual loss affecting the cornea
Keratitis
Painful visual loss affecting the iris
Anterior uveitis
Painful visual loss affecting the drainage angle
Acute angle-closure glaucoma
Painful visual loss affecting the optic nerve
Optic neuritis
Painful visual loss affecting the orbit
- Orbital cellulitis
- Endophthalmitis
Painless visual loss affecting the drainage angle
Primary open angle glaucoma
Painless visual loss affecting the lens
Cataract
Painless visual loss affecting the retina/macula
- Retinal detachment
- Central retinal vein occlusion
- Central retinal artery occlusion
- Macualar oedema
- Wet age related macular degeneration
- Vitreous haemorrhage
Definition of keratitis
Inflamation of the cornea
Microbial keratitis cause
Commonly infective
- Bacterial: staphylococcus, pseudomonas
- Viral: herpes
- Fungal: candida
Risk factors for microbial keratitis
- Contact lens
- A breech in the corneal epithelium eg trauma
- Dry eye
- Prolonged use of steroid drops
Which bacteria is the most common culprit in microbial keratitis in a contact lens wearer?
Pseudomonas aeruginosa
Clinical features of microbial keratitis
- Painful eye
- Red eye
- Purulent discharge
- Blurred vision
- Hypopyon (collection of WBCs)
- White corneal opacity = corneal ulcer
Investigations in microbial keratitis
- Stain with flourescein in to see epithelial defect
- Corneal scrape: gram stain and culture
Management of microbial keratitis
- Stop wearing contact lenses until healed
- Topical antibiotic drops eg ciprofloxacin, ofloxacin
Which structures make up the uvea?
Iris, ciliary muscle and choroid
Definition of anterior uveitis
Inflammation of the iris
Risk factors for anterior uveitis
- HLA-B27 allele
- Ankylosing spondylitis
- Psoriatic arthritis
- Reiter’s syndrome
- Inflammatory bowel disease
Clinical features of anterior uveitis
Symptoms
- Photophobia
- Red eye
- Watering
Signs
- Anterior chamber cells: WBCs floating in the anterior chamber
- Hypopyon
- Disorted pupil: due to posterior synechiae (adhesions from the iris to the lens)
Management of anterior uveitis
- Topical steroids: dexamethasone 0.1%
- If there is posterior synechiae: dilating drops (to try and break them)
Definition/pathophysiology of glaucoma
- Optic nerve damage
- With visual field defect
- Related to raised IOP (intraocular pressure)
What are the two main types of glaucoma?
Describe the normal aqueous pathway within the eye
- Aqueous humour is made by the ciliary body and secreted into the posterior chamber
- Aqueous passes through the pupil into anterior chamber
- Most of the aqueous leaves the eye via the trabecular meshwork → Schlemm’s canal → bloodstream
Pathogenesis of acute angle closure glaucoma
- Pupil dilation eg in dark conditions → peripheral iris “bunches up” → increased resistance to aqueous flow
- Build up of aqueous in posterior chamber → bows iris forward → closes drainage angle
Risk factors for acute angle glaucoma
- Female
- Small eyes
- Asian ethnicity
- Age
Clinical features of acute angle closure glaucoma
- IOP > 40mmHg
- Red eye
- Cloudy cornea
- Fixed, oval, irregularly dilated pupil
- Pain
- Watering
- Reduced vision
Management of acute angle closure glaucoma
- Immediate management: lower eye pressure
- Topical drops
- alpha 2 agonist
- beta blockers
- steroids
- Systemic
- Acetazolamide PO
- Topical drops
- Definitive treatment
- Laser peripheral iridotomy (bilateral)
Pathogenesis of primary open-angle glaucoma
Outflow of aqueous is impaired due to disruption of the trabecular mashwork channels eg extacellular material blocking RM spaces.
Risk factors for chronic open-angle glaucoma
- Age >60
- African
- Family history
- Myopia
- Diabetic
- Long tern steroid drops
Clinical features of primary open-angle glaucoma
- Patient asymptomatic as the disease is slowly progressive
- Raised IOP (>22mmHg)
- Optic nerve cup:disc ratio >0.4
- Loss of peripheral visual fields
Treatment of primary open-angle glaucoma
- Topical therapy
- Prostaglandin analogues: lantanoprost
- Beta-blockers: timolol
- Laser
- Surgery
- Trabeculectomy
Definition of retinal detachment
The potential space between the neuroretina and the retinal pigment epithelium (loosely attached in the eye) become separated.
Risk factors for retinal detachment
- Recent eye trauma
- Retinal detachment in the other eye
- High myope (large eye, so at risk of tears)
Clinical features of retinal detachment
- Flashing lights
- > 100 new floaters
- Shadow/curtain over vision
Treatment for retinal detachment
Urgent referral to ophthalmology for surgery (pars plana vitrectomy)
Pathophysiology of central retinal vein occlusion
- Usually related to Virchow’s triad of thrombogenesis
- Stasis
- Vessel wall damage
- Hypercoagulability
Risk factors for central retinal vein occlusion
- Age
- Hypertension
- Hyperlipidaemia
- Diabetes mellitus
- Smoker
Clinical features of central retinal vein occlusion
- Sudden, unilateral blurred vision
- Fundus findings
- Dilated tortuous veins
- Haemorrhages in all 4 quadrants of the retina
- Cotton wool spots
Management of central retinal vein occlusion
- No specific treatment for uncomplicated CRVO
- Allow time to settle (should settle in 3 to 6 months)
- Closely monitor
Complications of central retinal vein occlusion and their management
- Macular oedema
- Cysts of fluid form at macula
- Managment: intravitreal anti-VEGF injections
- Retinal neovascularisation
- New vessels in response to VEGF released from ischaemia retina
- New vessels are fragile and can bleed
- Managment: laser photocoagulation
Clinical features of central retinal artery occlusion
Managment of central retinal artery occlusion
-
Transfer to stroke unit
- Carotid Doppler US
- CT head angiogram
Definition of cataract
Opacification of the intraocular lens
Aetiology of cataract
Chemical and structural alteration of lens proteins (clear → opaque)
Risk factors for cataracts
- Old age
- Diabetes
- Steroid use (drops, PO)
- UV light exposure
Clinical features of cataracts
- Gradual (over years - decades) progressive loss of vision
- Glare at night
Treatment of cataracts
Phacoemulsification
Orbital cellulitis clinical features
- Lid: induration, warm erythema, tenderness, unable to open eye
- Fever
- Proptosis
- Chemosis
Features of dry and wet age related macular degeneration
- Drusen (yellow deposits of proteins and lipids)
- Atrophy of the retinal pigment epithelium
- Degeneration for eh photoreceptors
Features unique to wet AMD
Development of new vessels growing from the choroid layer into the retina.
Risk factors for age related macular degeneration
- Age
- Smoking
- White or Chinese ethnic origin
- Family history
- Cardiovascular disease
Presentation of AMD
- Gradual worsening central visual field loss
- Reduced visual acuity
- Crooked or wavy appearance to straight lines
Examination in AMD
- Reduced acuity using a Snellen chart
- Scotoma (a central patch of vision loss)
- Amsler grid test can be used to assess the distortion of straight lines
- Fundoscopy: drusen are the key finding
- Slit lamp biomicroscopic fundus examination by a specialist can be used to diagnose AMD
- Optical coherence tomography
- Fluorescein angiography
Management of dry age related macular degeneration
Managment of wet age related macular degeneration
Anti-VEGF medications (ranibizumab) are injected directly into the vitreous chamber of the eye once a month.
