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MRCSI (Ophth) Written study materials
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MRCSI (Ophth) Written practice questions

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Question 1Ophthalmology

Which retinal layer contains the photoreceptor cell bodies?

  1. Ganglion cell layer
  2. Outer nuclear layer Correct answer.
  3. Nerve fibre layer
  4. Inner nuclear layer

Explanation

Photoreceptor nuclei form the outer nuclear layer, lying between the outer limiting membrane and the outer plexiform layer. Ganglion cells and their axons occupy the inner retinal layers.

Question 2Ophthalmology

A patient reports sudden painless loss of vision in one eye with a dense inferior visual field defect. Which arterial occlusion is most likely?

  1. Branch retinal vein occlusion
  2. Anterior ischaemic optic neuropathy
  3. Superior branch retinal artery occlusion Correct answer.
  4. Central retinal vein occlusion

Explanation

A superior branch retinal artery occlusion infarcts the superior retina, which subserves the inferior visual field, producing sudden painless field loss. The retinal appearance is of sectorial pallor with a cherry-red spot at the macula if the fovea is involved.

Question 3Ophthalmology

Which finding is characteristic of primary open-angle glaucoma on optic disc examination?

  1. Increased cup-to-disc ratio with neuroretinal rim thinning Correct answer.
  2. Peripapillary atrophy with normal rim contour
  3. Disc hyperaemia with splinter haemorrhages only
  4. Bilateral disc swelling with obscuration of vessels

Explanation

Glaucomatous optic neuropathy is defined by progressive neuroretinal rim loss and cup enlargement, usually most marked inferiorly and superiorly. Splinter haemorrhages and peripapillary atrophy may accompany it but are not the defining feature.

Question 4Ophthalmology

A 65-year-old presents with a sudden curtain across the vision and flashes, then notices a shadow inferiorly. What is the most appropriate immediate action?

  1. Same-day dilated fundus examination for retinal detachment Correct answer.
  2. Prescribe topical steroids and review in one week
  3. Arrange routine visual field testing in six weeks
  4. Reassure and advise review only if vision worsens

Explanation

Photopsia with a new visual field defect suggests rhegmatogenous retinal detachment or a retinal tear, which requires urgent dilated examination and possible laser or surgery. Delay risks macular involvement and permanent visual loss.

Question 5Ophthalmology

Which organism most commonly causes bacterial keratitis associated with contact lens wear?

  1. Streptococcus pneumoniae
  2. Neisseria gonorrhoeae
  3. Pseudomonas aeruginosa Correct answer.
  4. Moraxella catarrhalis

Explanation

Pseudomonas aeruginosa is the classic contact-lens-associated corneal pathogen, capable of rapid stromal melting. It is Gram-negative and often resistant to standard empirical therapy, so fluoroquinolone cover is used.

Question 6Ophthalmology

A dendritic corneal ulcer staining with fluorescein and rose bengal is most consistent with which diagnosis?

  1. Herpes simplex epithelial keratitis Correct answer.
  2. Acanthamoeba keratitis
  3. Bacterial corneal ulcer
  4. Fungal keratitis

Explanation

A branching dendritic ulcer with terminal bulbs is the hallmark of herpes simplex epithelial keratitis. Rose bengal stains devitalised cells and highlights the dendritic pattern.

Question 7Ophthalmology

A patient with keratoconus is being assessed for refraction. Which finding is most typical?

  1. Hypermetropic shift with a shallow anterior chamber
  2. Myopic shift with a normal corneal topography
  3. Regular astigmatism with a clear central reflex
  4. Irregular astigmatism with scissoring on retinoscopy Correct answer.

Explanation

Keratoconus causes corneal thinning and conical protrusion, producing irregular astigmatism that shows scissoring of the retinoscopic reflex. Rigid contact lenses are often needed for visual rehabilitation.

Question 8Ophthalmology

Which is the most common cause of preventable blindness worldwide?

  1. Trachoma
  2. Cataract Correct answer.
  3. Glaucoma
  4. Diabetic retinopathy

Explanation

Cataract remains the leading cause of reversible blindness globally and is treatable with surgery. Glaucoma and diabetic retinopathy cause largely irreversible loss.

Question 9Ophthalmology

A 70-year-old reports gradual painless central visual loss with distortion and metamorphopsia. Which investigation is most useful initially?

  1. Gonioscopy
  2. Optical coherence tomography of the macula Correct answer.
  3. Automated perimetry
  4. Corneal topography

Explanation

Metamorphopsia with central loss suggests macular disease such as age-related macular degeneration or epiretinal membrane, for which OCT demonstrates fluid, drusen or membrane. Perimetry localises field loss but does not characterise macular structure.

Question 10Ophthalmology

Which type of age-related macular degeneration is treated with intravitreal anti-VEGF therapy?

  1. Peripheral drusen alone
  2. Neovascular (wet) AMD Correct answer.
  3. Geographic atrophy
  4. Reticular pseudodrusen without fluid

Explanation

Anti-VEGF agents target VEGF-driven choroidal neovascularisation in wet AMD, reducing exudation and preserving vision. Non-neovascular forms, including geographic atrophy, do not respond to anti-VEGF.

Question 11Ophthalmology

A diabetic patient has a sudden painless loss of vision with a preretinal haemorrhage obscuring the macula. What is the most likely diagnosis?

  1. Diabetic macular oedema
  2. Retinitis pigmentosa
  3. Central serous chorioretinopathy
  4. Proliferative diabetic retinopathy with vitreous haemorrhage Correct answer.

Explanation

Sudden painless visual loss in a diabetic with a preretinal or vitreous haemorrhage suggests proliferative diabetic retinopathy with neovascularisation bleeding. Urgent assessment and often panretinal photocoagulation or vitrectomy are required.

Question 12Ophthalmology

Which structure is the site of aqueous humour outflow in the normal eye?

  1. Ciliary body epithelium into the vitreous
  2. Trabecular meshwork into Schlemm canal Correct answer.
  3. Iris root into the anterior chamber
  4. Retinal pigment epithelium into the choroid

Explanation

Aqueous drains through the trabecular meshwork into Schlemm canal and then episcleral veins. This pathway is the target of trabeculectomy and many glaucoma drugs.

Question 13Ophthalmology

A patient with acute angle-closure glaucoma presents with a fixed mid-dilated pupil and a hazy cornea. Which initial medical therapy is most appropriate?

  1. Topical tropicamide alone
  2. Topical pilocarpine with systemic acetazolamide and hyperosmotic agents Correct answer.
  3. Topical atropine and systemic steroids
  4. Topical phenylephrine alone

Explanation

Acute angle closure is treated by lowering intraocular pressure with aqueous suppressants such as acetazolamide and hyperosmotics, plus pilocarpine to constrict the pupil once pressure falls. Definitive treatment is laser peripheral iridotomy.

Question 14Ophthalmology

Which is the most common cause of acquired cataract in adults?

  1. Age-related degeneration Correct answer.
  2. Systemic corticosteroid use
  3. Uveitis
  4. Ocular trauma

Explanation

Age-related (senile) cataract is by far the commonest cause of lens opacity in adults. Trauma, steroids and uveitis are recognised secondary causes but are less frequent.

Question 15Ophthalmology

A 3-year-old has a white pupillary reflex and leukocoria. Which diagnosis must be excluded urgently?

  1. Nasolacrimal duct obstruction
  2. Congenital glaucoma
  3. Optic nerve hypoplasia
  4. Retinoblastoma Correct answer.

Explanation

Leukocoria in a young child is retinoblastoma until proven otherwise and requires urgent referral. Other causes include congenital cataract and Coats disease, but malignancy must be excluded first.

Question 16Ophthalmology

Which is the most common type of strabismus in childhood?

  1. Infantile esotropia
  2. Brown syndrome
  3. Convergence excess esotropia
  4. Intermittent exotropia Correct answer.

Explanation

Intermittent exotropia is the commonest form of childhood strabismus, often presenting with distance exodeviation. Infantile esotropia is less frequent.

Question 17Ophthalmology

A patient with a third nerve palsy has ptosis and the eye is deviated down and out. Which additional finding would suggest a compressive cause requiring urgent imaging?

  1. Normal pupillary reactions
  2. Isolated ptosis
  3. Improved duction after rest
  4. A dilated pupil unreactive to light Correct answer.

Explanation

Pupil-involving third nerve palsy suggests compression, such as by a posterior communicating artery aneurysm, and warrants urgent neuroimaging. Pupil-sparing palsies are more often microvascular.

Question 18Ophthalmology

Which visual field defect is typical of a bitemporal hemianopia?

  1. Loss of both temporal fields from chiasmal compression Correct answer.
  2. Enlarged blind spot from papilloedema
  3. Loss of both nasal fields from optic tract lesions
  4. Homonymous loss from occipital infarction

Explanation

Bitemporal hemianopia results from compression of the optic chiasm, typically by a pituitary adenoma, interrupting crossing nasal fibres. It affects the temporal field of each eye.

Question 19Ophthalmology

A patient has a homonymous hemianopia with macular sparing. Which lesion location is most likely?

  1. Occipital cortex Correct answer.
  2. Lateral geniculate nucleus
  3. Optic chiasm
  4. Optic nerve

Explanation

Macular sparing occurs with occipital cortical lesions because the macula has a large representation supplied by both the posterior and middle cerebral arteries. Chiasmal and nerve lesions produce different patterns.

Question 20Ophthalmology

Which is the most common cause of optic neuritis in young adults?

  1. Neuromyelitis optica
  2. Sarcoidosis
  3. Multiple sclerosis Correct answer.
  4. Syphilis

Explanation

Optic neuritis in young adults is most often demyelinating and associated with multiple sclerosis. Neuromyelitis optica is a less common but important differential.

Question 21Ophthalmology

A patient presents with a painful, swollen eyelid and proptosis with restricted eye movements and fever. What is the most appropriate initial management?

  1. Oral antihistamines and review in one week
  2. Warm compresses and observation
  3. Topical antibiotic drops alone
  4. Urgent admission with intravenous antibiotics and imaging Correct answer.

Explanation

Orbital cellulitis is an emergency requiring intravenous antibiotics and imaging to exclude abscess. Delay risks cavernous sinus thrombosis and permanent visual loss.

Question 22Ophthalmology

Which is the most common cause of a watering eye in an infant?

  1. Orbital cellulitis
  2. Congenital glaucoma
  3. Nasolacrimal duct obstruction Correct answer.
  4. Retinoblastoma

Explanation

Congenital nasolacrimal duct obstruction is the commonest cause of epiphora in infancy and usually resolves spontaneously with massage. Congenital glaucoma is a rarer but more serious cause.

Question 23Ophthalmology

A patient with thyroid eye disease develops diplopia and marked proptosis with optic nerve compression. Which treatment is most appropriate for sight-threatening disease?

  1. High-dose systemic corticosteroids or urgent orbital decompression Correct answer.
  2. Topical lubricants alone
  3. Radioactive iodine alone
  4. Beta-blockers alone

Explanation

Dysthyroid optic neuropathy is sight-threatening and requires high-dose steroids, with orbital decompression if response is inadequate. Lubricants and beta-blockers address surface symptoms and systemic control but not compression.

Question 24Ophthalmology

Which is the most common cause of endogenous endophthalmitis?

  1. Direct inoculation during surgery
  2. Corneal perforation
  3. Contiguous spread from orbital cellulitis
  4. Haematogenous spread from a distant focus Correct answer.

Explanation

Endogenous endophthalmitis arises from haematogenous seeding, often from a liver abscess or endocarditis. Post-operative and post-traumatic cases are exogenous.

Question 25Ophthalmology

Which is the most appropriate first-line treatment for acute anterior uveitis?

  1. Oral antiviral therapy
  2. Topical corticosteroid with a cycloplegic Correct answer.
  3. Topical beta-blocker
  4. Topical antibiotic with a mydriatic

Explanation

Acute anterior uveitis is treated with topical steroids to suppress inflammation and a cycloplegic to relieve pain and prevent synechiae. Antibiotics and antivirals are not indicated unless a specific infection is identified.

Question 26Ophthalmology

Which layer of the cornea is primarily responsible for maintaining corneal transparency by regulating its hydration?

  1. Descemet's membrane
  2. Corneal endothelium Correct answer.
  3. Corneal epithelium
  4. Bowman's layer

Explanation

The endothelium is a monolayer of pump cells that actively removes fluid from the stroma, keeping the collagen lamellae at a critical hydration for transparency. Loss of endothelial cells leads to stromal oedema and haze.

Question 27Ophthalmology

A patient reports a sudden curtain descending over vision in one eye, preceded by brief episodes of transient visual loss. Which diagnosis fits best?

  1. Retinal detachment Correct answer.
  2. Vitreous haemorrhage
  3. Amaurotic transient ischaemia from carotid disease
  4. Central retinal vein occlusion

Explanation

A progressive shadow or curtain across the visual field with preceding amaurosis fugax suggests a rhegmatogenous retinal detachment, often with a retinal tear. Urgent fundoscopy and referral for surgical repair are required.

Question 28Ophthalmology

Which finding on slit-lamp examination is characteristic of a pterygium rather than a pinguecula?

  1. A fleshy fibrovascular growth that crosses the limbus onto the cornea Correct answer.
  2. A yellow deposit confined to the conjunctiva nasal to the limbus
  3. A raised gelatinous nodule that never involves the cornea
  4. A subconjunctival haemorrhage with no tissue elevation

Explanation

A pterygium is a wing-shaped fibrovascular growth of conjunctiva that extends across the limbus onto the cornea, whereas a pinguecula remains confined to the conjunctiva. Corneal involvement is the key distinguishing feature.

Question 29Ophthalmology

A 55-year-old with a painful red eye has a shallow anterior chamber, corneal epithelial oedema and an intraocular pressure of 48 mmHg. Which mechanism best explains the raised pressure?

  1. Reduced episcleral venous drainage
  2. Increased aqueous production by the ciliary body
  3. Obstruction of trabecular outflow by iris apposition Correct answer.
  4. Excess protein blocking the trabecular meshwork

Explanation

In acute angle closure the peripheral iris apposes the trabecular meshwork, blocking aqueous outflow and causing a rapid pressure rise. Treatment aims to relieve the block and lower pressure.

Question 30Ophthalmology

Which organism is the most frequent cause of bacterial keratitis associated with contact lens wear?

  1. Staphylococcus aureus
  2. Moraxella catarrhalis
  3. Pseudomonas aeruginosa Correct answer.
  4. Streptococcus pneumoniae

Explanation

Pseudomonas aeruginosa is the classic cause of contact lens-associated microbial keratitis, particularly with extended wear or poor hygiene. It can progress rapidly and cause corneal melting.

Question 31Ophthalmology

A patient has a pupil that constricts briskly to light but the consensual response is absent in the fellow eye, with normal visual acuity. Which structure is most likely affected?

  1. Optic nerve Correct answer.
  2. Ciliary ganglion
  3. Iris sphincter
  4. Oculomotor nerve

Explanation

An afferent pupillary defect reflects optic nerve or extensive retinal dysfunction; the affected eye shows a reduced direct response when light is swung from the normal eye. Normal acuity does not exclude optic neuropathy.

Question 32Ophthalmology

Which clinical feature most strongly suggests giant cell arteritis in an older patient with sudden visual loss?

  1. Painless proptosis
  2. Scalp tenderness and jaw claudication Correct answer.
  3. Bilateral ptosis
  4. Epiphora and photophobia

Explanation

Giant cell arteritis classically presents with headache, scalp tenderness, jaw claudication and an elevated ESR/CRP, and can cause anterior ischaemic optic neuropathy. Immediate high-dose corticosteroids are indicated to protect the fellow eye.

Question 33Ophthalmology

A neonate has a positive red reflex test showing a white pupillary reflex. Which condition must be excluded first?

  1. Optic disc drusen
  2. Congenital cataract Correct answer.
  3. Congenital glaucoma
  4. Retinopathy of prematurity

Explanation

A white pupillary reflex in a newborn requires urgent evaluation for congenital cataract and retinoblastoma. Early surgery for dense cataract is needed to prevent irreversible amblyopia.

Question 34Ophthalmology

A patient with known sickle cell disease develops a hyphema after blunt trauma. Which complication is most characteristic?

  1. Choroidal melanoma
  2. Sympathetic ophthalmia
  3. Corneal perforation
  4. Raised intraocular pressure from sickled cells obstructing outflow Correct answer.

Explanation

In sickle cell disease, hyphema can precipitate sickling in the anterior chamber, obstructing the trabecular meshwork and causing marked pressure elevation. Management avoids carbonic anhydrase inhibitors that may worsen sickling and uses topical agents.

Question 35Ophthalmology

Which feature distinguishes a hordeolum from a chalazion?

  1. A painless, hard, chronic granulomatous swelling
  2. A diffuse preseptal cellulitis
  3. An acute, painful, tender lid margin abscess Correct answer.
  4. A fleshy eyelid margin tumour

Explanation

A hordeolum is an acute infection of the lid margin glands, producing a painful, tender swelling. A chalazion is a chronic lipogranuloma that is typically painless and hard.

Question 36Ophthalmology

Which test is most appropriate to confirm a diagnosis of dry eye disease in a symptomatic patient?

  1. Visual evoked potentials
  2. Gonioscopy
  3. Indirect ophthalmoscopy
  4. Tear film break-up time and Schirmer test Correct answer.

Explanation

Dry eye is assessed with tear film stability (break-up time), tear production (Schirmer test) and ocular surface staining. These directly measure the tear film and surface integrity.

Question 37Ophthalmology

A patient has vertical diplopia that worsens on looking down and to the right, with a right hypertropia that increases on right head tilt. Which muscle is most likely affected?

  1. Left inferior oblique
  2. Right superior oblique Correct answer.
  3. Right inferior rectus
  4. Left superior rectus

Explanation

A right superior oblique palsy causes right hypertropia that worsens on left gaze and on right head tilt (positive Bielschowsky test). This reflects weakness of the depressor and intortor of the right eye.

Question 38Ophthalmology

Which structure produces aqueous humour?

  1. Trabecular meshwork
  2. Corneal endothelium
  3. Iris pigment epithelium
  4. Ciliary epithelium Correct answer.

Explanation

Aqueous humour is secreted by the ciliary epithelium of the ciliary body. It then flows through the pupil into the anterior chamber and drains via the trabecular meshwork.

Question 39Ophthalmology

A patient with diabetes has a sudden painless visual loss with a preretinal haemorrhage obscuring the macula. Which management is most appropriate?

  1. Observation with tight glycaemic and blood pressure control Correct answer.
  2. Immediate vitrectomy
  3. Intravitreal anti-VEGF injection into the affected eye
  4. Laser photocoagulation of the macula

Explanation

A dense premacular haemorrhage often clears spontaneously, so observation with control of systemic risk factors is appropriate initially. Vitrectomy is reserved for non-clearing or recurrent haemorrhage.

Question 40Ophthalmology

Which finding on fundoscopy is characteristic of central retinal artery occlusion?

  1. A cherry-red spot at the macula with a pale retina Correct answer.
  2. A yellow subretinal membrane
  3. Widespread flame haemorrhages with a swollen disc
  4. A pale optic disc with cupping

Explanation

CRAO produces a pale, opaque retina with a cherry-red spot at the fovea because the underlying choroidal circulation remains visible through the thin fovea. Vision loss is sudden and painless.

Question 41Ophthalmology

A patient has a painless, slowly enlarging pigmented lesion at the eyelid margin with loss of lashes. Which diagnosis should be suspected?

  1. Squamous papilloma
  2. Basal cell carcinoma
  3. Chalazion
  4. Sebaceous carcinoma Correct answer.

Explanation

Sebaceous carcinoma often arises at the lid margin, can mimic blepharitis, and causes loss of lashes (madarosis). It is aggressive and requires wide excision.

Question 42Ophthalmology

Which is the most appropriate initial treatment for a patient with an acute chemical splash to the eye?

  1. Topical corticosteroid drops
  2. Topical antibiotic ointment alone
  3. Pressure patching of the eye
  4. Immediate copious irrigation with saline or water Correct answer.

Explanation

Chemical injury requires immediate copious irrigation to dilute and remove the agent, followed by assessment of limbal ischaemia and pH. Delay in irrigation worsens prognosis.

Question 43Ophthalmology

A patient reports flashes and floaters with a new inferior visual field defect. Which examination finding most strongly indicates a retinal tear?

  1. A cotton wool spot
  2. A macular hole
  3. A horseshoe-shaped retinal break with surrounding subretinal fluid Correct answer.
  4. A posterior vitreous detachment alone

Explanation

A horseshoe tear with subretinal fluid indicates a rhegmatogenous detachment requiring urgent laser or surgery. Flashes and floaters alone suggest vitreous traction without a break.

Question 44Ophthalmology

Which ocular finding is most consistent with keratoconus?

  1. Inferior corneal steepening with a scissoring reflex on retinoscopy Correct answer.
  2. A ring-shaped lipid deposit at the limbus
  3. A central corneal ulcer with hypopyon
  4. Superior corneal flattening with a regular reflex

Explanation

Keratoconus produces inferior corneal steepening, irregular astigmatism and a scissoring retinoscopic reflex. Corneal topography confirms the diagnosis.

Question 45Ophthalmology

Which visual field defect is typical of a lesion at the optic chiasm?

  1. Bitemporal hemianopia Correct answer.
  2. Enlarged blind spot
  3. Homonymous hemianopia
  4. Central scotoma

Explanation

The chiasm contains crossing fibres from the nasal retina, so a chiasmal lesion produces a bitemporal hemianopia. Pituitary adenoma is a common cause.

Question 46Ophthalmology

A patient with a history of herpes zoster ophthalmicus develops a red eye with reduced corneal sensation. Which complication should be suspected?

  1. Bacterial conjunctivitis
  2. Retinal detachment
  3. Acute angle closure
  4. Neurotrophic keratitis Correct answer.

Explanation

Herpes zoster ophthalmicus can damage the ophthalmic division of the trigeminal nerve, causing neurotrophic keratitis with reduced sensation and epithelial breakdown. Management includes lubrication and treatment of epithelial defects.

Question 47Ophthalmology

A patient with thyroid eye disease has marked proptosis and optic nerve compression with reduced acuity and a relative afferent pupillary defect. Which treatment is most appropriate?

  1. Orbital radiotherapy as sole therapy
  2. High-dose intravenous corticosteroids Correct answer.
  3. Radioactive iodine
  4. Topical lubricants alone

Explanation

Dysthyroid optic neuropathy is an emergency treated with high-dose intravenous corticosteroids; orbital decompression is considered if vision does not improve. Lubricants are supportive only.

Question 48Ophthalmology

A patient with a painful red eye and photophobia has fine keratic precipitates, cells in the anterior chamber and a constricted pupil. Which is the most appropriate initial treatment?

  1. Topical prostaglandin analogue
  2. Topical corticosteroid and cycloplegic drops Correct answer.
  3. Topical antibiotic drops
  4. Oral antiviral therapy

Explanation

Acute anterior uveitis is treated with topical corticosteroids to control inflammation and cycloplegics to relieve pain and prevent synechiae. An underlying cause should be investigated.

Question 49Ophthalmology

Which finding on optical coherence tomography is most consistent with active choroidal neovascularisation?

  1. Subretinal fluid with an irregular hyperreflective subretinal membrane Correct answer.
  2. A dome-shaped elevation of the retinal pigment epithelium with drusen only
  3. A full-thickness macular hole
  4. A hyperreflective epiretinal membrane with retinal wrinkling

Explanation

Active neovascular age-related macular degeneration shows subretinal or intraretinal fluid with a neovascular membrane on OCT. Anti-VEGF therapy is indicated.

Question 50Ophthalmology

A patient has a gradual painless loss of peripheral vision with a cup-to-disc ratio of 0.8 and a nasal step on perimetry. Which diagnosis is most likely?

  1. Papilloedema
  2. Anterior ischaemic optic neuropathy
  3. Optic neuritis
  4. Primary open-angle glaucoma Correct answer.

Explanation

Progressive peripheral field loss with optic disc cupping and a nasal step is characteristic of primary open-angle glaucoma. Treatment aims to lower intraocular pressure.