MRCSI (Ophth) Written — Ophthalmic Surgery (RCSI, Ireland)

Which of the following nerves or nerve branches passes OUTSIDE the common tendinous ring (annulus of Zinn) at the superior orbital fissure?

• AAbducens nerve (CN VI)
• BTrochlear nerve (CN IV)
• CNasociliary nerve (branch of CN V1)
• DSuperior division of the oculomotor nerve (CN III)

Which of the following ocular structures is derived embryologically from the surface ectoderm?

• ACrystalline lens
• BNeural retina
• CIris sphincter muscle
• DSclera

Which of the following arterial systems provides the primary blood supply to the lamina cribrosa of the optic nerve head?

• ACentral retinal artery
• BShort posterior ciliary arteries
• CAnterior ciliary arteries
• DPial vessel plexus alone

Which of the following extraocular muscles does NOT originate from the common tendinous ring (annulus of Zinn) at the apex of the orbit?

• ASuperior oblique muscle
• BInferior oblique muscle
• CLateral rectus muscle
• DSuperior rectus muscle

A congenital iris coloboma is typically located in the inferonasal quadrant. This abnormality is caused by the failure of closure of which embryonic structure?

• AOptic fissure
• BLens vesicle
• CNeural tube
• DPrimary vitreous

Which of the following layers of the cornea comprises approximately 90% of the total corneal thickness?

• AEpithelium
• BStroma
• CBowman's layer
• DDescemet's membrane

The preganglionic parasympathetic fibers that mediate pupillary constriction travel along the oculomotor nerve (CN III) and synapse in which of the following ganglia?

• ACiliary ganglion
• BSuperior cervical ganglion
• CPterygopalatine ganglion
• DTrigeminal ganglion

Which of the following bones does NOT form part of the medial wall of the orbit?

• AMaxillary bone
• BEthmoid bone
• CLacrimal bone
• DZygomatic bone

The vortex veins, which drain the major venous network of the uveal tract, typically exit the sclera at which location relative to the rectus muscles?

• ADirectly beneath the insertions of the rectus muscles
• BNear the equator, in the quadrants between the rectus muscles
• CAdjacent to the optic nerve head
• DAt the limbus

Which of the following muscles is primarily responsible for voluntary, tight closure of the eyelids (forced squeeze)?

• ALevator palpebrae superioris muscle
• BOrbicularis oculi muscle (orbital portion)
• COrbicularis oculi muscle (palpebral portion)
• DSuperior tarsal muscle (Müller's muscle)

Which of the following physiological processes is the primary contributor to aqueous humor production by the ciliary body?

• AUltrafiltration
• BSimple diffusion
• CActive secretion
• DOsmosis

During the resting state in the dark, which of the following describes the electrical and chemical state of retinal photoreceptor cells?

• AHyperpolarized with low intracellular cGMP
• BDepolarized with high intracellular cGMP
• CHyperpolarized with high intracellular sodium
• DDepolarized with low intracellular sodium

Which of the following transport systems in the corneal endothelium is most critical for maintaining corneal deturgescence and clarity?

• ANa+/K+ ATPase pump
• BCa2+ ATPase pump
• CProton pump (H+ ATPase)
• DGlucose transporter 1 (GLUT1)

In the physiology of binocular vision, what is the term for the spatial curve containing all points in space that project to corresponding points on the two retinas?

• APanum's fusional area
• BHoropter
• CStereopsis zone
• DDiplopia threshold

How does the avascular crystalline lens obtain its primary supply of glucose and other essential nutrients?

• ADirectly from the choroid via vitreous diffusion
• BFrom the central retinal artery
• CFrom the aqueous humor
• DFrom the ciliary body blood vessels

Which specific isomer of retinal is bound to opsin in rhodopsin in the resting (unexcited) state in the dark?

• AAll-trans retinal
• B11-cis retinal
• C9-cis retinal
• D13-cis retinal

Which layer of the preocular tear film is produced by the meibomian glands and primarily serves to prevent evaporation of the underlying aqueous layer?

• AMucin layer
• BAqueous layer
• CLipid layer
• DGlycocalyx layer

According to the Goldmann equation, intraocular pressure (IOP) is directly proportional to the rate of aqueous humor production and which of the following variables?

• AOutflow resistance
• BOutflow facility
• CTrabecular meshwork surface area
• DUveoscleral outflow rate

Which histopathological staining method is utilized to confirm the presence of amyloid deposits showing green birefringence under polarized light in Lattice corneal dystrophy?

• AMasson trichrome
• BCongo red
• CAlcian blue
• DPeriodic acid-Schiff (PAS)

Which of the following histopathological structures is the classic, pathognomonic rosette formation seen in retinoblastoma representing photoreceptor differentiation?

• AFlexner-Wintersteiner rosettes
• BHomer-Wright rosettes
• CCall-Exner bodies
• DPsammoma bodies

Which of the following pathogens is a free-living protozoan that causes a severe, painful keratitis characteristically associated with poor contact lens hygiene?

• AAcanthamoeba species
• BFusarium species
• CPseudomonas aeruginosa
• DHerpes simplex virus

A temporal artery biopsy is performed in a suspected case of giant cell arteritis (GCA). Which of the following histological findings is considered pathognomonic?

• ACaseating granulomatous necrosis of the adventitia
• BDisruption of the internal elastic lamina with multinucleated giant cells
• CFibrinoid necrosis of the muscular media with neutrophilic infiltration
• DLeukocytoclastic vasculitis of the vasa vasorum

What is the earliest histopathological change observed in the retinal vasculature of a patient with diabetic retinopathy?

• ALoss of intramural pericytes
• BEndothelial cell hyperplasia
• CMicroaneurysm formation
• DNeovascularization at the disc

A neonate presents with hyperacute purulent conjunctivitis and chemosis 3 days after birth. Which of the following organisms is the most likely causative agent?

• AChlamydia trachomatis
• BNeisseria gonorrhoeae
• CHerpes simplex virus (HSV)
• DStaphylococcus aureus

What is the primary biochemically identified constituent of drusen located beneath the retinal pigment epithelium (RPE) in age-related macular degeneration?

• AHyaluronic acid
• BLipoproteins and extracellular proteins
• CGlycogen
• DCalcium phosphate deposits

Which of the following histopathological changes in the optic nerve is considered a classic finding in advanced, end-stage glaucomatous optic neuropathy?

• ADemyelinating plaques with perivascular cuffing
• BCavernous degeneration of Schnabel
• CCaseating granulomas with Langhans giant cells
• DHemorrhagic necrosis of the optic nerve head

What is the primary mechanism of action of the prostaglandin analog latanoprost in lowering intraocular pressure?

• ADecreasing aqueous humor production by the ciliary epithelium
• BIncreasing aqueous humor outflow via the uveoscleral pathway
• CIncreasing aqueous humor outflow via the trabecular meshwork
• DCausing pupillary constriction to open the iridocorneal angle

A patient is prescribed oral acetazolamide for acute intraocular pressure reduction. Which of the following systemic side effect profiles is most typically associated with this medication?

• AMetabolic acidosis with hypokalemia
• BMetabolic alkalosis with hyperkalemia
• CMetabolic acidosis with hyperkalemia
• DMetabolic alkalosis with hypokalemia

Which of the following describes the mechanism of action of pilocarpine when used to treat angle-closure glaucoma?

• ASelective alpha-2 adrenergic receptor agonist decreasing aqueous inflow
• BMuscarinic acetylcholine receptor agonist causing ciliary muscle contraction
• CBeta-adrenergic receptor antagonist reducing cyclic AMP in the ciliary body
• DProstaglandin receptor agonist altering the ciliary body extracellular matrix

Which of the following topical cycloplegic agents has the longest duration of action, typically lasting up to 10-12 days?

• ATropicamide
• BCyclopentolate
• CHomatropine
• DAtropine

What is the pharmacological mechanism of action of ranibizumab, used in the treatment of neovascular age-related macular degeneration?

• ARecombinant humanized monoclonal antibody fragment targeting all isoforms of VEGF-A
• BSoluble decoy receptor fusion protein binding VEGF-A, VEGF-B, and PlGF
• CPegylated RNA aptamer binding specifically to the VEGF-165 isoform
• DSmall molecule tyrosine kinase inhibitor blocking intracellular VEGF receptors

Which of the following topical corticosteroids has the highest risk of inducing an elevation in intraocular pressure (steroid response)?

• AFluorometholone 0.1%
• BLoteprednol etabonate 0.5%
• CDexamethasone sodium phosphate 0.1%
• DRimexolone 1%

Which of the following autonomic drops is a selective alpha-1 adrenergic agonist that produces pupillary dilation (mydriasis) without causing cycloplegia?

• APhenylephrine
• BTropicamide
• CCyclopentolate
• DApraclonidine

What is the primary mechanism of action of ganciclovir, which is commonly used to treat cytomegalovirus (CMV) retinitis?

• AInhibition of viral DNA polymerase via competitive integration
• BInhibition of viral reverse transcriptase
• CInhibition of viral protease and assembly
• DInhibition of viral entry into the host cell

Which of the following local anesthetics is most commonly used topically in the outpatient clinic for measuring intraocular pressure via Goldmann applanation tonometry?

• AProparacaine (Proxymetacaine)
• BLidocaine
• CBupivacaine
• DCocaine

What is the typical inheritance pattern of familial, hereditary retinoblastoma, and which gene is mutated?

• AAutosomal dominant; RB1 gene
• BAutosomal recessive; RB1 gene
• CX-linked recessive; RB1 gene
• DAutosomal dominant; NF1 gene

A patient presents with rapid, sequential, painless loss of central vision in both eyes. Genetic testing confirms Leber hereditary optic neuropathy (LHON). What is the inheritance pattern of this condition?

• AMitochondrial inheritance
• BAutosomal dominant
• CAutosomal recessive
• DX-linked dominant

Which of the following tear film osmolarity thresholds is generally accepted as clinically indicative of dry eye disease (keratoconjunctivitis sicca)?

• AGreater than 308 mOsm/L
• BLess than 280 mOsm/L
• CExactly 290 mOsm/L
• DGreater than 350 mOsm/L

Which of the following systemic chromosomal abnormalities is most strongly associated with an increased incidence of keratoconus?

• ADown syndrome (Trisomy 21)
• BTurner syndrome (45, XO)
• CKlinefelter syndrome (47, XXY)
• DEdward syndrome (Trisomy 18)

Which cell type is primarily responsible for corneal stromal wound healing and scar formation after injury or refractive surgery?

• ACorneal epithelial cells
• BActivated stromal keratocytes
• CCorneal endothelial cells
• DConjunctival goblet cells

What is the spherical equivalent of the following spectacle lens prescription: -3.00 DS / -1.50 DC x 180?

• A-3.00 DS
• B-3.75 DS
• C-4.50 DS
• D-3.50 DS

A patient is wearing a spectacle lens prescription of +4.00 DS. If the patient looks 5 mm (0.5 cm) nasally from the optical center of the lens, what is the induced prismatic effect?

• A2.0 prism diopters base out
• B2.0 prism diopters base in
• C0.2 prism diopters base out
• D0.2 prism diopters base in

During streak retinoscopy at a working distance of 67 cm (using a working distance lens of +1.50 D), you observe 'with-motion' in the vertical meridian. What lens type should you add to move toward neutralization?

• APlus spherical lenses
• BMinus spherical lenses
• CPlus cylinder lenses at axis 180
• DConcave mirror setting adjustments only

What is the transposed cylinder form of the following spectacle lens prescription: +2.00 DS / -1.00 DC x 90?

• A+1.00 DS / +1.00 DC x 180
• B+1.00 DS / -1.00 DC x 180
• C+2.00 DS / +1.00 DC x 180
• D+3.00 DS / -1.00 DC x 180

A patient has a spectacle refraction of -10.00 DS at a vertex distance of 12 mm. What is the correct power of the contact lens to prescribe for this patient?

• A-9.00 DS
• B-11.25 DS
• C-10.00 DS
• D-8.00 DS