Ophthalmology - Drugs and the eye in systemic disease Flashcards
What classification system is used for hypertensive retinopathy?
Keith-Wagner classification:
1) Tortuosity and silver wiring
2) AV nipping
3) Flame haemorrhages and soft cotton wool spots
4) Papilloedema
Grades 3 and 4 = malignant hypertension
What granulomatous disorders can affect the eye?
TB, sarcoid, toxoplasmosis, leprosy, brucella
All of these tend to manifest as uveitis (ant/post) and choroidoretinitis
What systemic inflammatory conditions are associated with conjunctivitis?
SLE, reactive arthritis, IBD
What systemic inflammatory conditions are associated with scleritis/episcleritis?
RA, vasculitis, SLE, IBD
What systemic inflammatory conditions are associated with iritis?
Ank spond, IBD, sarcoid
What eye condition is dermatomyositis associated with?
Retinopathy
What is keratoconjunctivitis sicca?
This is associated with Sjogrens syndrome.
Patients have decreased tear production (as tested using Schirmer’s test: <5mm in 5 min) leading to dry eyes as well as dry mouth.
Sicca syndromes can be primary (i.e. as a feature of Sjogrens) or secondary to other diseases - e.g. RA, SLE and sarcoid
Treatment is with artificial tears or saliva
What conditions can cause vascular occlusion of vessels in the eye?
Emboli cause amourosis fugax (transient loss of vision); associated with GCA or carotid emboli
Microemboli cause Roth spots seen typically in infective endocarditis
- these appear as a boat shaped haemorrhage with a pale centre
Name some metabolic conditions that cause eye changes?
Kayser-Fleischer Rings = Wilson’s disease (copper accumulation)
Exophthalmos = Graves
Corneal calcification = Hyperparathyroidism (HPT)
How can HIV/AIDS affect the eye?
CMV retinitis - presents as “pizza pie” fundus + flames
Occurs when the CD4 count is <50
Oral ganciclovir is the treatment of choice
HIV retinopathy presents with cotton wool spots
What are mydriatic drugs?
Mydriasis means dilating the pupil (as opposed to miotics which constrict the pupil). Mydriatics are drugs that cause pupil dilatation.
2 broad groups of drugs cause mydriasis 1) anti-muscarinics and 2) sympathomimetic agents
1) Anti-muscarinics - block parasympathetic input to constrictor pupillae muscles on the iris carried by CN3
- Tropicamide - 3h duration
- Cyclopentolate - 24h duration; preferred for paeds
Both cause pupil dilatation and loss of light reflexes Ciliary paralysis (cylcloplegia) causes blurred vision
2) Sympathomimetic agents - mimic sympathetic input into the eye
- parahydroxyamphetamine, phenylephrine
- may be used with tropicamide
- do NOT affect the light or accomodation reflex
Mydriatics are indicated for eye examination and to prevent synechiae in ant. uveitis/ iritis
They can cause acute glaucoma if shallow anterior chamber
What are miotics?
These are agents that cause pupil constriction. The most widely used agent is pilocarpine (muscarinic antagonist). They are mainly used to treat acute angle closure glaucoma.
What is Tetracaine?
Anaesthetic used to permit examination of a painful eye
Outline the drug treatment of chronic angle closure glaucoma?
1st line = beta blockers
- e.g. timolol, betaxolol
- decrease aqueous production
- caution in asthma, heart failure
2nd line = prostaglandin analogues
- e.g. lantoprost, travoprost
- increase uveoscleral outflow
3rd line = alpha agonists
- e.g. brimonidine, apraclonidine
- decrease aqueous production and increase uveoscleral outflow
Carbonic anhydrase inhibitors (used for AACG)
- e.g. dorzolamide drops, acetazolamide PO
Miotics
e.g. pilocarpine
