PassMedicine

Question 1

Which condition presents with a fixed dilated pupil with conjunctival injection?

Answer 1

Acute closed-angle glaucoma

Question 2

What is the immediate treatment for acute closed-angle glaucoma?

Answer 2

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.

Question 3

Which drops cause the eye to dilate?

Answer 3

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)

Question 4

Mechanism of action of dorzolamide eye drops?

Answer 4

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.

Question 5

Compare the treatment for herpes zoster ophthalmicus, herpes simplex keratitis and herpes zoster oticus

Answer 5

Herpes zoster ophthalmicus: Oral acyclovir

Herpes simplex keratitis: Topical acyclovir

Herpes zoster oticus (Ramsay-Hunt syndrome): Oral acyclovir 7 days, oral prednisolone 5 days

Question 6

What condition should you check for in a patient with an acute onset of painful red eye and visual loss shortly after ocular surgery?

Answer 6

Post-operative endophthalmitis

This is an infection of the aqueous and vitreous humour of the eye.

Question 7

4 complications post-cataract surgery

Answer 7

1. Posterior capsule opacification
2. Retinal detachment
3. Posterior capsule rupture
4. Endophthalmitis

Question 8

In which condition is there a large bullous retinal detachment?

Answer 8

rhegmatogenous retinal detachment

Question 9

What is the mechanism of action of timolol in primary open-angle glaucoma?

Answer 9

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.

Question 10

Corneal abrasion - what is the best next step of management?

Answer 10

topical antibiotics should be given to prevent secondary bacterial infection

Question 11

Following panretinal laser photocoagulation, what symptoms do up to 50% of patients have?

Answer 11

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.

Question 12

Medications used for anterior uveitis?

Answer 12

steroid + cycloplegic (mydriatic) drops

Question 13

‘red hue’ prior to total vision loss

Answer 13

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

Question 14

Following ocular trauma, an assessment should be made for what?

Answer 14

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.

Question 15

What is hyphema?

Answer 15

Blood in the anterior chamber of the eye

Question 16

Why do we worry about hyphema after ocular trauma?

Answer 16

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

Question 17

Why is strict bed rest required after ocular trauma?

Answer 17

excessive movement can redisperse blood that had previously settled

Question 18

What are the features of orbital compartment syndrome?

Answer 18

eye pain/swelling
proptosis
‘rock hard’ eyelids
relevant afferent pupillary defect

Question 19

What is an important differential for sudden visual loss in diabetics?

Answer 19

Vitreous haemorrhage

Question 20

What can non-compliance with treatment for exotropia lead to?

Answer 20

Ambylopia (lazy eye) - the brain fails to fully process inputs from one eye and over time favours the other eye

Question 21

What is the difference between a concomitant and paralytic squint?

Answer 21

Question 22

How can a squint be detected in a child?

Answer 22

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

Question 23

Why do patients with orbital cellulitis require admission to hospital for IV antibiotics?

Answer 23

due to the risk of cavernous sinus thrombosis and intracranial spread

Question 24

What is orbital cellulitis?

Answer 24

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.

Question 25

Why should you ask for a vaccination history in a patient with ?orbital cellulitis?

Answer 25

Lack of Haemophilus influenzae type b (Hib) vaccination is a risk factor

Question 26

How do you differentiate orbital from preseptal cellulitis?

Answer 26

reduced visual acuity, proptosis, ophthalmoplegia/pain with eye movements are NOT consistent with preseptal cellulitis

Question 27

night blindness + tunnel vision

Answer 27

Retinitis pigmentosa ## Footnote 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.

Question 28

What is vitelliform macular dystrophy?

Answer 28

This disorder typically affects central vision due to the accumulation of yellow deposits under the macula, causing distortion or loss of central vision.

Question 29

What is the first line treatment of primary open-angle glaucoma if IOP is ≥ 24 mmHg?

Answer 29

360° selective laser trabeculoplasty (SLT) ## Footnote 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.

Question 30

What is thought to be the pathophysiology in diabetic retinopathy?

Answer 30

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.

Question 31

What is wet AMD characterised by?

Answer 31

choroidal neovascularisation ## Footnote 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.

Question 32

Risk factors for scleritis?

Answer 32

* rheumatoid arthritis: the most commonly associated condition * systemic lupus erythematosus * sarcoidosis * granulomatosis with polyangiitis

Question 33

What is the management for scleritis?

Answer 33

* 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)

Question 34

What is the definitive treatment for acute angle-closure glaucoma?

Answer 34

Laser peripheral iridotomy

Question 35

Which pathogen should be suspected in contact lens associated keratitis?

Answer 35

Pseudomonas aeruginosa ## Footnote This will require ophthalmological review and antibiotic treatment with a topical quinolone.

Question 36

What is the most common pathogen in bacterial keratitis?

Answer 36

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.

Question 37

sudden painless loss of vision, severe retinal haemorrhages on fundoscopy, diabetic

Answer 37

Central retinal vein occlusion ## Footnote 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.

Question 38

red desaturation

Answer 38

Optic neuritis

Question 39

Why might patients with TB get optic neuritis?

Answer 39

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.

Question 40

How is dry AMD managed?

Answer 40

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

Question 41

How may squints be classified as to where the eye deviates toward?

Answer 41

* the nose: esotropia * temporally: exotropia * superiorly: hypertropia * inferiorly: hypotropia

Question 42

Acute severe eye pain and redness with associated features of systemic upset (e.g. nausea and/or vomiting) suggest a diagnosis of what?

Answer 42

acute angle-closure glaucoma

Question 43

sudden painless loss of vision, severe retinal haemorrhages on fundoscopy

Answer 43

Central retinal vein occlusion

Question 44

What are the causes of CRAO?

Answer 44

It is due to thromboembolism (from atherosclerosis) or arteritis (e.g. temporal arteritis)

Question 45

What is a potential complication of panretinal photocoagulation?

Answer 45

Decrease in night vision ## Footnote 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.

Question 46

What is a cause of red eye that is classically painful and may be associated with reduced visual acuity and blurred vision?

Answer 46

Scleritis

Question 47

What are the aims of treatment in acute glaucoma?

Answer 47

Reducing aqueous secretion + inducing pupillary constriction ## Footnote 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.

Question 48

Compare third nerve palsy and Horner's

Answer 48

Ptosis + dilated pupil = third nerve palsy; ptosis + constricted pupil = Horner's

Question 49

Which is the most likely complication of panretinal laser photocoagulation?

Answer 49

Following panretinal laser photocoagulation up to 50% of patients have a noticeable reduction in their visual field

Question 50

What is a central scotoma?

Answer 50

a blind spot in the centre of the visual field seen in optic neuritis

Question 51

If anisocoria is worse in bright light, what does this indicate?

Answer 51

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

Question 52

What are some causes of mydriasis (large pupil)?

Answer 52

third nerve palsy Holmes-Adie pupil traumatic iridoplegia phaeochromocytoma congenital

Question 53

Which drugs cause mydriasis?

Answer 53

topical mydriatics: tropicamide, atropine sympathomimetic drugs: amphetamines, cocaine anticholinergic drugs: tricyclic antidepressants

Question 54

Which type of squint (convergent or divergent) more common?

Answer 54

Convergent squints (esotropia), where one or both eyes turn inward, are more common than divergent squints (exotropia), where one or both eyes turn outward.

Question 55

What is a simple and effective method that can be used to screen for strabismus (squint) in children?

Answer 55

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.

Question 56

DIlated pupil, females, absent leg reflexes

Answer 56

Holmes Adie syndrome

Question 57

Keith-Wagener classification of hypertensive retinopathy?

Answer 57

## Footnote 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)

Question 58

What is a possible complication of scleritis?

Answer 58

Perforation of the globe ## Footnote Other complications of scleritis include glaucoma, cataracts, raised intraocular pressure, retinal detachment, and uveitis.