Ophthalmology - Red Eyes (Acute Closed Angle Glaucoma, Anterior Uveitis, episcleritis and scleritis) Flashcards
What is the pathophysiology of acute closed angle glaucoma?
-Glaucoma: optic nerve damage caused by significant rise in intraocular pressure -Occurs when iris bulges forwards and seals off trabecular meshwork - prevents aqueous humour drainage -Leads to build up of pressure in posterior chamber -Ophthalmological emergency
Name some risk factors for acute angle glaucoma
- Age -F 4x > M
- FHx: must screen people (annual, > 40 ya) with 1st degree affected relative
- Chinese/East Asian origin
Name some medications which can precipitate AAG
-Adrenergic medication: noradrenalin -Anticholinergics: oxybutynin -TCAs: amitryptaline (anticholinergic effect)
What is the presentation (sx) of AAG?
- Pt unwell, headache, N+V
- V painful eye
- Blurred vision
- Halos around light (due to corneal swelling)
What will you see on examination in a patient with AAG?
- Red, teary eye
- Hazy cornea
- Decreased visual acuity
- Dilatation of affected pupil + fixed pupil size
- Firm eyeball on palpation
What investigations should you perform in suspected AAG?
- Automated perimetry: assesses visual fields
- Slip lamp examination to look at fundus
- Goldmann applanation tonometry: measures IOP
- Corneal thickness measurement (used to calibrate tonometry)
- Gonioscopy: assesses peripheral anterior chamber configuration and depth
How would you manage AAG in GP waiting for an ambulance?
Patient needs same day assessment by ophthalmology
Immediate Mx waiting for ambulance:
- pilocarpine eye drops: muscarinic agonist - causes constriction of pupil and ciliary constriction, encourages flow of humour from ciliary body
- acetazolamide 500mg PO: carbonic anhydrase inhibitor, reduces production of aqueous humour
- analgesia + antiemetic
Apart from pilocarpine and acetazolamide, what other drugs can you give to reduce IOP?
- Hyperosmotic agents: glycerol/mannitol - increase osmotic gradient between blood and fluid in eye
- Timolol: beta locker - reduces production of aqueous humour
- Dorzolamide: carbonic anhydrase inhibitor - reduces production of aqueous humour
- Brimonidine: sympathomimetic - reduces production of aqueous humour and increases uveoscleral outflow
What is the definitive treatment for AAG if drug treatment fails?
-Laser iridotomy: laser made hole in iris to allow aqueous humour to flow into anterior chamber - relieves pressure that was pushing iris against cornea and humour can drain
What is anterior uveitis?
- Inflammation of the anterior part of the uvea (includes iris, ciliary body and choroid)
- Inflammation and immune cells (neutrophils, lymphocytes, macrophages) infiltrate the anterior chamber of eye.
- Causes: autoimmune (main cause), infection, trauma, ischaemia or malignancy
- Can be acute or chronic (>3/12)
Name some important associations of acute anterior uveitis
Associated with HLA B27 conditions
- Ankylosing spondylitis
- IBD
- Reactive arthritis
What are the symptoms of anterior uveitis?
- Usually unilateral with spontaneous onset
- Floaters and flashes
- Ciliary flush: ring of red spreading from cornea outwards
- Reduced visual acuity
- Miosis (shincter muscle contraction) and abnormal shaped pupil (posterior adhesions pull the iris into a weird shape)
- Photophobia: due to ciliary spasm
- Pain of movement
- Excessive lacrimation
How do you manage a patient with suspected anterior uveitis?
-Must refer patients with potentially sight threatening causes of red eye for same day ophthalmology assessment.
-Full slit lamp assessment
-Tonometry (Goldmann applanation): assesses IOP pressure Management
-Steroids: topical/PO/IV (ophthalmologist’s choice) -
Cycloplegic medication: cyclopentolate or atropine (paralysis ciliary muscles to cause dilatation and stop pain of ciliary spasm)
-Laser therapy in extreme cases
What is episcleritis?
- Benign and self limiting inflammation of the episclera (outermost layer of the sclera, which is just underneath clear conjunctiva)
- Common in young/middle aged adults and not usually caused by infection.
- Linked to RA and IBD
Outline the PC of someone with episcleritis
- Typically not painful
- Segmental redness (instead of diffuse) -eg patch of redness in lateral sclera
- Foreign body sensation
- Dilated episcleral vessels: mobile vessels when gentle pressure is applied vs in scleritis where vessels are deeper and do not move
- Watery eye but no discharge
What is this?
Episcleritis: localised redness on lateral aspect of eye
What is this?
Episcleritis: signs of deeper infection
