Opthalmology Flashcards
Cause of cherry-red spot at the macula
Often seen in Central retinal artery occlusion (CRAO)
suspect CRAO if there is sudden painless loss of vision
Sight-threatening causes of red eye
Acute glaucoma
Anterior uveitis
Corneal ulcer
Neonatal conjunctivitis
Trauma
Chemical injuries
Scleritis
Endophthalmitis
Pt presents with:
painful red eye, constricted fixed oval pupils, photophobia and decreased vision
Acute Uveitis
Conditions associated with anterior uveitis
Acute ant. uveitis associated with HLA B27 related conditions:
Ankylosing spondylitis
Inflammatory bowel disease
Reactive arthritis
Chronic anterior uveitis associated with:
Sarcoidosis
Syphilis
Lyme disease
Tuberculosis
Herpes
What is the “Uvea” made up of?
Iris
Ciliary body
Choroid
Management of anterior uveitis
Refer SAME DAY (urgent) referral to ophthal
- steroids
- Cycloplegic meds (paralyzing ciliary muscles - reducing pain associated with ciliary spasm) and mydriatic meds (dilates the pupils)
- e.g. cyclopentolate & atropine
- Immunosuppressants (DMARDS, TNF inhibitors)
What is a hypopyon
collection of white blood cells in the anterior chamber, seen as a yellowish fluid collection settled in front of the lower iris, with a fluid level
What is Acute Angle Closure Glaucoma
Glaucoma = optic nerve damage caused by a significant rise in intraocular pressure
Angle-closure refers to when the iris bulges forward and seals off the trabecular meshwork from the anterior chamber - preventing Aq. humour from being able to drain away
OPHTHAL EMERGENCY
What is open-angle galucoma
Where there is a gradual increase in resistance through the trabecular meshwork.
This makes it more difficult for aqueous humour to flow through the meshwork and exit the eye.
Therefore the pressure slowly builds within the eye and this gives a slow and chronic onset of glaucoma.
What is normal Intraocular pressure
10-21mmHg
What causes “cupping” of optic disc? What is an abnormal optic cup to disc ratio?
Raised intraocular pressure e.g. glaucoma
If the optic cup is > 0.5 size of the optic disc = abnormal
Risk factors for glaucoma
Increasing age
Family history
Black ethnic origin
Nearsightedness (myopia)
Clinical features of open angle glaucoma
Often asymptomatic, gradual onset, picked up during screening at optician
Peripheral vision affected –> tunnel vision
Halo around lights at night
Fluctuating pain/headaches
blurred vision
How to measure intraocular pressure
Tonometry (non-contact or goldman application)
At what introcular pressure is treatment started in open angle glaucoma
> =24 mmHg
Management of open angle glaucoma
Prostaglandin analogues (Latanoprost)
Topical beta-blockers (Timolol)
Carbonic anhydrase inhibitors (Dorzolamide)
Sympathomimetics (Brimonidine)
Trabeculectomy
Medications that can precipitate closed-angle glaucoma
Adrenergic meds (e.g. noradrenaline)
Anticholinergic meds (e.g. oxybutynin)
TCAs (which have anticholinergic effects)
Initial management for acute angle closure glaucoma (before ophthal review)
Lie pt on their back
Pilocarpine eye drops (2% for blue eyes, 4% for brown eyes)
Acetazolemide 500mg orally
Analgesia
Antiemetics
Definitive treatment of acute angle closure glaucoma
Laser iridotomy (creates a hole in the iris so Aq humour can drain)
Features of optic neuritis
Unilateral decrease in visual acuity over hours/days
Red desaturation
Pain worse on eye movement
RAPD
Central Scotoma
What is a central scotoma and what causes it?
blind spot directly in the center of your vision (directly in your line of sight)
Caused by: disorders of the optic nerve, choroid or retina, such as macular degeneration
5 year risk of developing multiple sclerosis after episode of optic neuritis
50%
Why is orbital cellulitis a medical emergency
risk of cavernous sinus thrombosis and intracranial spread
Where is affected in orbital cellulitis and periorbital cellulitis?
Periorbital = eyelid + skin, anterior to the orbital septum
Orbital = infection around eyeball, involving tissues behind septum
Features differentiating orbital cellulitis from periorbital cellulitis
Pain on eye movement
Reduced eye movements
Changes in vision
Abnormal pupil reactions
Proptosis
Systemically unwell
CT Scan can differentiate
Complications of orbital cellulitis
Orbital abscess
Extra-orbital extension of infection (rare but V bad)
Visual loss - from optic neuritis or central rential v./a. occlusion
Intracranial involeent (meningitis, abscess, thrombosis in cavenous sinuses)
Treatment of orbital cellulitis
ADMIT
Prompt CT, ENT and ophthalmic opinion
AbX - cefotaxime IV + metronidazole +/- vancomycin
May need surgical drainage if very severe
What bacterial is typical for bacterial keratitis
Staphlococcus aureus
Contact lens wearer: Pseudomonas aeruginosa
What is endophthalmitis
purulent inflammation of the intraocular fluids (vitreous and aqueous) usually due to infection
(Tx = intravitreal abx, sometimes vitrectomy)
New onset flashes or floaters
Should be urgently referred to ophthal
Could be retinal detachment
Retinal detachment - the 4 Fs
Floaters
Flashers
Field loss
Failing acuity
Papilloedema - findings on fundoscopy
Venous engorgement
Blurring of the optic disc margin
Elevation of the optic disc
Paton’s lines: concentrial retinal lines cascading from the optic disc
Clinical features of vitreous haemorrhage
painless visual loss or haze
red hue in the vision
floaters or shadows/dark spots in the vision
Clinical features of retinal detachment
Dense shadow that starts peripherally progresses toward the central vision
A veil or curtain over the field of vision
Straight lines appear curved
Central visual loss
Clinical features of vitreous detachment
(May precede retinal detachment)
Flashes / Floaters - often on the temporal side of central vision
