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
What is orbital cellulitis?
the result of an infection affecting the fat and muscles posterior to the orbital septum, within the orbit but not involving the globe
Periorbital (preseptal) cellulitis is a less serious superficial infection anterior to the orbital septum, resulting from a superficial tissue injury (chalazion, insect bite etc…). Periorbital cellulitis can progress to orbital cellulitis.
Why should you ask for a vaccination history in a patient with ?orbital cellulitis?
Lack of Haemophilus influenzae type b (Hib) vaccination is a risk factor
How do you differentiate orbital from preseptal cellulitis?
reduced visual acuity, proptosis, ophthalmoplegia/pain with eye movements are NOT consistent with preseptal cellulitis
night blindness + tunnel vision
Retinitis pigmentosa
Retinitis pigmentosa is a group of inherited retinal disorders characterized by progressive degeneration of the retina, leading to night blindness and peripheral vision loss. The patient’s symptoms of poor night vision and developing ‘tunnel vision’, as well as a family history of visual problems leading to blindness, are classic features of retinitis pigmentosa.
What is vitelliform macular dystrophy?
This disorder typically affects central vision due to the accumulation of yellow deposits under the macula, causing distortion or loss of central vision.
What is the first line treatment of primary open-angle glaucoma if IOP is ≥ 24 mmHg?
360° selective laser trabeculoplasty (SLT)
SLT is a laser procedure that increases aqueous outflow through the trabecular meshwork and is the first-line treatment of POAG in patients with an IOP greater than or equal to 24 mmHg. It can effectively lower IOP while reducing the need for eye drops in some patients, although this is not always the case.
What is thought to be the pathophysiology in diabetic retinopathy?
Hyperglycaemia is thought to cause increased retinal blood flow and abnormal metabolism in the retinal vessel walls. This precipitates damage to endothelial cells and pericytes
Endothelial dysfunction leads to increased vascular permeability which causes the characteristic exudates seen on fundoscopy. Pericyte dysfunction predisposes to the formation of microaneurysms. Neovasculization is thought to be caused by the production of growth factors in response to retinal ischaemia.
What is wet AMD characterised by?
choroidal neovascularisation
Dry age-related macular degeneration is characterised by drusen, here described as small accumulations of extracellular material between Bruch’s membrane and the retinal pigment epithelium of the eye.
Risk factors for scleritis?
- rheumatoid arthritis: the most commonly associated condition
- systemic lupus erythematosus
- sarcoidosis
- granulomatosis with polyangiitis
What is the management for scleritis?
- same-day assessment by an ophthalmologist
- oral NSAIDs are typically used first-line
- oral glucocorticoids may be used for more severe presentations
- immunosuppressive drugs for resistant cases (and also to treat any underlying associated diseases)
What is the definitive treatment for acute angle-closure glaucoma?
Laser peripheral iridotomy
Which pathogen should be suspected in contact lens associated keratitis?
Pseudomonas aeruginosa
This will require ophthalmological review and antibiotic treatment with a topical quinolone.
What is the most common pathogen in bacterial keratitis?
Staph aureus
This is normally the most common cause of bacterial keratitis. However, in patients regularly using contact lenses, Pseudomonas aeruginosa is the most common cause.
sudden painless loss of vision, severe retinal haemorrhages on fundoscopy, diabetic
Central retinal vein occlusion
As the vein becomes blocked excess fluid and blood leak into the retina and appear as severe haemorrhages (sometimes referred to a cheese and tomato pizza appearance). It causes sudden, painless loss of vision in one eye.
red desaturation
Optic neuritis
Why might patients with TB get optic neuritis?
The anti-tuberculous agent ethambutol can be associated with optic neuritis.
This often presents first with deficits in colour vision, particularly red desaturation. In one study, abnormal colour vision was recognised in 94% of patients with optic neuritis.
How is dry AMD managed?
There is no curative medical treatment for dry AMD. High dose of beta-carotene, vitamins C and E, and zinc can be given to slow deterioration of visual loss
How may squints be classified as to where the eye deviates toward?
- the nose: esotropia
- temporally: exotropia
- superiorly: hypertropia
- inferiorly: hypotropia
Acute severe eye pain and redness with associated features of systemic upset (e.g. nausea and/or vomiting) suggest a diagnosis of what?
acute angle-closure glaucoma
sudden painless loss of vision, severe retinal haemorrhages on fundoscopy
Central retinal vein occlusion
What are the causes of CRAO?
It is due to thromboembolism (from atherosclerosis) or arteritis (e.g. temporal arteritis)
What is a potential complication of panretinal photocoagulation?
Decrease in night vision
Pan-retinal laser photocoagulation utilises a laser to create numerous micro-burns across the peripheral retina. These burns serve to eradicate the newly formed blood vessels that arise due to neovascularisation from diabetic retinopathy. An acknowledged side effect of this intervention is a possible diminution in night vision. This occurs because the rods, which are crucial for vision under low-light conditions, predominantly reside in the peripheral retina. The laser can therefore cause damage to these rods, leading patients to experience impaired night vision.
What is a cause of red eye that is classically painful and may be associated with reduced visual acuity and blurred vision?
Scleritis
What are the aims of treatment in acute glaucoma?
Reducing aqueous secretion + inducing pupillary constriction
Acute glaucoma, also known as acute angle-closure glaucoma, is a medical emergency characterised by a sudden increase in intraocular pressure (IOP) due to impaired drainage of aqueous humour. The primary aims of treatment are to reduce IOP and relieve the patient’s symptoms. This can be achieved by reducing the production of aqueous humour and constricting the pupil, which helps to open up the drainage angle and promote outflow. Medications such as topical beta-blockers, alpha agonists, and carbonic anhydrase inhibitors can be used to decrease aqueous secretion, while miotic agents like pilocarpine help in inducing pupillary constriction.
Compare third nerve palsy and Horner’s
Ptosis + dilated pupil = third nerve palsy; ptosis + constricted pupil = Horner’s
Which is the most likely complication of panretinal laser photocoagulation?
Following panretinal laser photocoagulation up to 50% of patients have a noticeable reduction in their visual field
What is a central scotoma?
a blind spot in the centre of the visual field
seen in optic neuritis
If anisocoria is worse in bright light, what does this indicate?
The pupil is unable to constrict properly and that the parasympathetic innervation is not working properly.
Problems with the parasympathetic innervation of the eye can involve the parasympathetic nervous system entirely, the oculomotor nerve, the ciliary ganglion, or the iris itself
What are some causes of mydriasis (large pupil)?
third nerve palsy
Holmes-Adie pupil
traumatic iridoplegia
phaeochromocytoma
congenital
Which drugs cause mydriasis?
topical mydriatics: tropicamide, atropine
sympathomimetic drugs: amphetamines, cocaine
anticholinergic drugs: tricyclic antidepressants
Which type of squint (convergent or divergent) more common?
Convergent squints (esotropia), where one or both eyes turn inward, are more common than divergent squints (exotropia), where one or both eyes turn outward.
What is a simple and effective method that can be used to screen for strabismus (squint) in children?
The corneal light reflex, also known as the Hirschberg test
It involves shining a light into the child’s eyes and observing the reflection on their corneas. If the reflections are symmetrical, it suggests normal alignment of the eyes. However, if they are asymmetrical, this may indicate a squint.
DIlated pupil, females, absent leg reflexes
Holmes Adie syndrome
Keith-Wagener classification of hypertensive retinopathy?
When you earn SILVER (1), you get a NIP and tuck (II), then you trade your clothes made of COTTON and WOOL to something more hot/FLAME (III). When you start dressing hot you get a new PAPI (IV)
What is a possible complication of scleritis?
Perforation of the globe
Other complications of scleritis include glaucoma, cataracts, raised intraocular pressure, retinal detachment, and uveitis.
