PassMedicine Flashcards
Which condition presents with a fixed dilated pupil with conjunctival injection?
Acute closed-angle glaucoma
What is the immediate treatment for acute closed-angle glaucoma?
Pilocarpine eye drops and admit to hospital
In the primary care setting, the person should be laid flat to relieve angle pressure. Pilocarpine eye drops (to constrict the pupil) and oral acetazolamide (to reduce aqueous humour production) should be administered.
Which drops cause the eye to dilate?
Atropine
Tropicamide
Do NOT give these in acute close-angle glaucoma
Worse in a dark room (cinema) as pupils dilate —> closing angle further. This worsens vision / pain.
So piloCarpine given to open the angle back up by constricting the pupil (C = constrict)
Mechanism of action of dorzolamide eye drops?
Carbonic anhydrase inhibitor
which works by decreasing the production of aqueous humour in the eye, thereby reducing intraocular pressure. This makes it useful in the management of conditions such as glaucoma where there is raised intraocular pressure.
Compare the treatment for herpes zoster ophthalmicus, herpes simplex keratitis and herpes zoster oticus
Herpes zoster ophthalmicus: Oral acyclovir
Herpes simplex keratitis: Topical acyclovir
Herpes zoster oticus (Ramsay-Hunt syndrome): Oral acyclovir 7 days, oral prednisolone 5 days
What condition should you check for in a patient with an acute onset of painful red eye and visual loss shortly after ocular surgery?
Post-operative endophthalmitis
This is an infection of the aqueous and vitreous humour of the eye.
4 complications post-cataract surgery
- Posterior capsule opacification
- Retinal detachment
- Posterior capsule rupture
- Endophthalmitis
In which condition is there a large bullous retinal detachment?
rhegmatogenous retinal detachment
What is the mechanism of action of timolol in primary open-angle glaucoma?
Reduces aqueous secretion by the ciliary body
Beta blockers act by reducing aqueous secretion by the ciliary body.
Prostaglandin analogues act by increasing aqueous outflow via the uveoscleral route.
Sympathomimetics act by reducing aqueous secretion and increasing aqueous outflow.
Miotics act by opening the aqueous drainage channels in the trabecular meshwork.
Diode laser cycloablation destroys part of the secretory component of the ciliary body, thereby reducing aqueous secretion.
Corneal abrasion - what is the best next step of management?
topical antibiotics should be given to prevent secondary bacterial infection
Following panretinal laser photocoagulation, what symptoms do up to 50% of patients have?
noticeable reduction in their visual field (peripheral vision)
PRP aims to prevent further retinal neovascularisation by creating areas of retinal scarring, reducing oxygen demand. However, this scarring can lead to a reduction in peripheral vision, as the laser treatment primarily affects the outer retinal areas. This side effect is well-documented and aligns with the patient’s new visual symptoms. While other complications like decreased night vision and macular oedema can occur, they are less common and typically secondary to the more prominent loss of peripheral vision caused by the treatment.
Medications used for anterior uveitis?
steroid + cycloplegic (mydriatic) drops
‘red hue’ prior to total vision loss
vitreous haemorrhage
painless loss of vision with floaters and ‘red hue’ is typical of vitreous haemorrhage.
Furthermore, this is worst when lying flat as this causes the blood to pool on the macula, thereby worsening central vision
Following ocular trauma, an assessment should be made for what?
orbital compartment syndrome as this may require immediate decompression prior to imaging etc
The appropriate management at this stage is to perform an urgent lateral canthotomy in order to prevent permanent vision loss.
What is hyphema?
Blood in the anterior chamber of the eye
Why do we worry about hyphema after ocular trauma?
The main risk to sight comes from raised intraocular pressure which can develop due to the blockage of the angle and trabecular meshwork with erythrocytes
Why is strict bed rest required after ocular trauma?
excessive movement can redisperse blood that had previously settled
What are the features of orbital compartment syndrome?
eye pain/swelling
proptosis
‘rock hard’ eyelids
relevant afferent pupillary defect
What is an important differential for sudden visual loss in diabetics?
Vitreous haemorrhage
What can non-compliance with treatment for exotropia lead to?
Ambylopia (lazy eye) - the brain fails to fully process inputs from one eye and over time favours the other eye
What is the difference between a concomitant and paralytic squint?
How can a squint be detected in a child?
Detection of a squint may be made by the corneal light reflection test - holding a light source 30cm from the child’s face to see if the light reflects symmetrically on the pupils
Why do patients with orbital cellulitis require admission to hospital for IV antibiotics?
due to the risk of cavernous sinus thrombosis and intracranial spread