NRE Step 1 Ophthalmology MCQs

Answer: Laser peripheral iridotomy. This is acute angle-closure glaucoma. Lower the pressure urgently (e.g. IV acetazolamide, topical beta-blocker, pilocarpine once pressure starts to fall — per the eye team), then perform laser peripheral iridotomy to open a drainage route. The fellow eye is treated prophylactically because it shares the narrow-angle anatomy.

• Topical steroid drops: Steroid drops treat uveitis; they do not open a closed drainage angle.
• Atropine drops: Atropine dilates the pupil and crowds the angle further, worsening the attack.
• Trabeculectomy as first step: Filtering surgery is for uncontrolled glaucoma; iridotomy treats pupil block first.

Answer: Treat amblyopia. A persistent squint after about 3 months of age needs referral. The brain suppresses the image from the deviating eye, causing amblyopia, which becomes permanent if untreated during the sensitive period (until about 7–8 years). Treatment includes correcting refractive error with glasses and occlusion (patching) of the good eye or atropine penalisation; surgery may be needed for alignment.

• Straighten the eye for appearance: Appearance matters, but the main aim is to prevent permanent amblyopia while the visual system is still developing.
• Strengthen the weak muscle: Squint is not treated with eye exercises; the priority is the amblyopia.
• Prevent future myopia: Squint treatment has no effect on whether myopia develops.

Answer: Orbital rhabdomyosarcoma. Childhood proptosis: orbital cellulitis (commonest — febrile, painful, acute), capillary haemangioma (infancy, grows then involutes), dermoid cyst (slow, superotemporal), rhabdomyosarcoma (most common primary orbital malignancy; average age ~7; rapid painless proptosis, often superonasal mass with downward displacement, ptosis, lid swelling — urgent CT/MRI and biopsy; chemotherapy ± radiotherapy, good survival when localised), neuroblastoma metastasis (bilateral, periorbital bruising — "raccoon eyes"), leukaemic infiltration (chloroma), optic nerve glioma (NF1). Adults: thyroid eye disease is the commonest cause of uni- or bilateral proptosis.

• Thyroid eye disease: Thyroid eye disease is rare in children and progresses slowly.
• Orbital cellulitis: Orbital cellulitis is febrile and painful.
• Capillary haemangioma: Capillary haemangioma appears in infancy, grows, then regresses.

Answer: Excision + conjunctival autograft. Pterygium: degenerative fibrovascular growth of bulbar conjunctiva onto the cornea (crosses the limbus), usually nasal; associated with chronic UV exposure, hot dry dusty climates, outdoor work. Pinguecula — yellowish nodule that does not cross onto the cornea. Pterygium symptoms: irritation, redness, cosmetic concern, induced astigmatism, visual axis encroachment. Treatment: lubricants and sunglasses for mild; surgery when progressive, affecting vision or causing astigmatism: excision with conjunctival autograft (or amniotic membrane) and/or antimetabolite (mitomycin C) — bare sclera excision has high recurrence (often > 30–50%). Recurrences can be more aggressive.

• Bare-sclera excision: Bare-sclera excision has a high recurrence rate.
• Topical antibiotics: A pterygium is not infective, so antibiotics do nothing.
• Wait until it reaches the pupil: Waiting until it reaches the pupil makes surgery harder and vision worse.

Answer: Relieve spasm, stop synechiae. Anterior uveitis management: topical corticosteroid (e.g. prednisolone acetate 1% hourly initially, then tapered) to suppress inflammation; cycloplegic-mydriatic (cyclopentolate 1% or atropine 1%) to paralyse the ciliary muscle (relieving photophobia/pain from spasm) and dilate the pupil, which prevents and breaks posterior synechiae (which can cause iris bombé and angle-closure glaucoma) and stabilises the blood–aqueous barrier. Monitor IOP (uveitis and steroids can raise it). Severe/posterior/recurrent disease needs periocular/systemic steroids or immunosuppressants. Investigate recurrent or bilateral disease (HLA-B27, sarcoidosis, TB, syphilis).

• Lower intraocular pressure: Cyclopentolate does not lower IOP; it can even raise it.
• Constrict the pupil: Cyclopentolate dilates the pupil; it does not constrict it.
• Reduce inflammation directly: The steroid reduces inflammation; cyclopentolate relieves spasm and prevents synechiae.

Answer: Neovascular glaucoma. Neovascular glaucoma: retinal ischaemia (ischaemic CRVO — "90-day glaucoma", proliferative diabetic retinopathy, ocular ischaemic syndrome/carotid disease) releases VEGF → new vessels on the iris (rubeosis iridis) and angle → fibrovascular membrane closes the angle → very high IOP, pain, poor vision. Treatment: treat the ischaemia (panretinal photocoagulation), intravitreal anti-VEGF to regress new vessels quickly, IOP control (topical/oral agents; avoid pilocarpine), topical steroid and atropine for comfort; surgery (glaucoma drainage device) or cyclodiode laser for refractory cases; prognosis often poor. Ischaemic CRVO needs monitoring for rubeosis for months.

• Acute angle closure: Angle closure has no history of vein occlusion or iris new vessels.
• Steroid-induced glaucoma: There is no steroid exposure.
• Open-angle glaucoma: New iris vessels close the angle, so this is not open-angle glaucoma.

Answer: Urgent dilated retinal exam. Posterior vitreous detachment (PVD): age-related liquefaction and separation of the vitreous from the retina (earlier in myopes, after cataract surgery or trauma) → flashes (photopsia — vitreous traction) and floaters (Weiss ring). About 10–15% of acute symptomatic PVDs have a retinal tear; tears allow fluid under the retina → rhegmatogenous detachment. Red flags: shower of floaters, pigment in the vitreous ("tobacco dust" — Shafer sign, strongly suggests tear), vitreous haemorrhage, visual field shadow/curtain, reduced acuity. Management: dilated fundoscopy (indirect ophthalmoscopy with indentation) within 24 hours; laser or cryo retinopexy for tears; safety-net advice to return immediately with a curtain.

• Routine review in 3 months: Three months is too long; a retinal tear must be excluded now.
• Reassure — floaters are benign: New flashes and floaters may hide a retinal tear.
• MRI brain: The symptoms are retinal, not intracranial.

Answer: Optic disc drusen. Pseudopapilloedema (elevated disc without raised ICP): optic disc drusen (hyaline/calcified deposits — buried in children, more visible with age), hypermetropic crowded discs, myelinated nerve fibres, tilted discs. Clues: lumpy disc margins, vessels clearly visible over the disc, no hyperaemia/haemorrhages/exudates, spontaneous venous pulsation often present, normal patient; drusen glow on autofluorescence and are hyperechoic on B-scan; OCT helps. Drusen can cause slowly progressive field defects. True papilloedema (raised ICP): bilateral disc swelling with venous engorgement, loss of venous pulsation, flame haemorrhages, obscured vessels at the margin, enlarged blind spot; headache, vomiting, transient visual obscurations — urgent neuroimaging before LP. Misdiagnosis leads to unnecessary scans and LPs, while missing true papilloedema is dangerous.

• Papilloedema: Papilloedema has venous engorgement, haemorrhages and absent venous pulsation.
• Optic neuritis: Optic neuritis is painful with reduced vision.
• Malignant hypertension: Malignant hypertension causes haemorrhages and exudates.

Answer: Topical anaesthetic abuse. Topical anaesthetics (proparacaine, tetracaine/amethocaine, oxybuprocaine) are for examination and procedures only. Repeated use is toxic to corneal epithelium (inhibits migration and mitosis), abolishes protective blink and pain signals, and leads to persistent epithelial defects, ring infiltrates (sterile immune), stromal melt and perforation — may mimic Acanthamoeba or fungal keratitis. Management: stop the drops (address dependence/psychological issues), preservative-free lubricants, prophylactic antibiotics, bandage lens/amniotic membrane, keratoplasty for perforation. Similar caution applies to over-the-counter steroid–antibiotic combinations, which mask and worsen infections (especially fungal and herpetic) and cause glaucoma/cataract.

• Normal healing: Normal healing does not cause a ring infiltrate and melting.
• Allergy to tears: Allergy does not cause corneal melting.
• Acanthamoeba keratitis: Acanthamoeba is linked to contact lenses, not anaesthetic drop use.

Answer: Amblyopia — glasses, then patch. Amblyopia: reduced best-corrected vision from abnormal visual experience in early childhood. Types: strabismic, anisometropic (unequal refraction — one eye blurred, often with straight eyes so it goes unnoticed without screening), stimulus deprivation (cataract, ptosis — most severe), bilateral ametropic. Treatment is most effective before ~7–8 years: correct refractive error (spectacles alone improve many — "refractive adaptation" for ~16–18 weeks), then patching the better eye (2–6 hours/day) or atropine penalisation of the better eye; monitor for reverse amblyopia; adherence is key. Vision screening at school entry (4–5 years) detects it.

• No problem — eyes straight: Straight eyes do not exclude anisometropic amblyopia.
• Squint surgery: There is no squint to operate on.
• Patch only, no glasses: Glasses must be worn first; patching follows if amblyopia persists.

Answer: Darkening of the iris and lash growth. Glaucoma drops: prostaglandin analogues (latanoprost, travoprost, bimatoprost — first-line; ↑ uveoscleral outflow; once nightly): iris heterochromia (brown), eyelash lengthening, periocular pigmentation, conjunctival hyperaemia, cystoid macular oedema. β-blockers (timolol — ↓ aqueous production): bronchospasm, bradycardia — avoid in asthma, heart block. α2-agonists (brimonidine): allergy, CNS depression in infants. Carbonic anhydrase inhibitors (dorzolamide; oral acetazolamide — paraesthesia, acidosis, stones). Miotics (pilocarpine — ↑ trabecular outflow; angle closure).

• Bronchospasm: Bronchospasm is a side effect of timolol.
• Metabolic acidosis and paraesthesia: Acidosis and paraesthesia are side effects of acetazolamide.
• Miosis and brow ache: Miosis and brow ache are side effects of pilocarpine.

Answer: Pinguecula. Pinguecula: yellowish degenerative (elastotic) conjunctival lesion adjacent to the limbus (usually nasal), from UV/dust exposure; doesn’t invade cornea; lubricants for irritation. Pterygium: triangular fibrovascular growth from conjunctiva onto the cornea (nasal), UV-related, common in sunny/dusty Pakistan; can cause astigmatism and threaten the visual axis → excision with conjunctival autograft (reduces recurrence), mitomycin C. Phlycten: hypersensitivity nodule (TB, staphylococcus).

• Pterygium: A pterygium encroaches onto the cornea.
• Conjunctival melanoma: Melanoma is pigmented and growing.
• Phlycten: A phlycten is an inflammatory nodule at the limbus.