OP10.1-7 | Miscellaneous Skills, Emergencies and Community Ophthalmology — Practice Quiz

Correct. Equal angle in all gazes with full ductions = comitant strabismus. Onset before 6 months with unilateral fixation preference and reduced VA in the deviated eye = amblyopia. This is the hallmark of infantile esotropia.

Comitant strabismus has an equal deviation angle in all positions of gaze with full ductions; incomitant strabismus has a varying angle due to a muscle or nerve deficit. This child has infantile (congenital) esotropia — a comitant, unilateral deviation with associated amblyopia from constant suppression.

Incorrect. CN palsy causes incomitant strabismus — the angle varies with gaze direction and ductions are restricted in the affected field. Here, ductions are full and the angle is equal everywhere, confirming a comitant deviation. The direction (inward = eso) and the VA reduction (amblyopia) point to infantile esotropia.

Correct. CN VI = lateral rectus only (mnemonic LR6SO4). Failure to abduct the right eye, with the deviation worsening in right gaze, is a classic right CN VI palsy. Diabetes-related ischaemic mononeuropathy is the most common aetiology in this age group.

CN VI (abducens) supplies only the lateral rectus. Isolated failure of abduction — worse when looking in the direction of the paralysed muscle — is the hallmark. Diabetes is the most common cause of isolated CN VI palsy (ischaemic mononeuropathy).

Incorrect. CN III palsies cause failure of adduction, elevation, and depression plus ptosis and pupil involvement. CN IV palsy produces a vertical/torsional diplopia worse on downgaze. CN VII is a purely motor nerve to the face with no role in eye movements. Isolated abduction failure = CN VI palsy.

Correct. Both distance and near acuities are normal and pinhole makes no change, ruling out a refractive error. Asthenopia that is purely task-related with normal acuities is the fingerprint of convergence insufficiency — the exophoria decompensates during sustained near vergence effort.

Normal distance VA (6/6) and near VA (N6) with normal pinhole, yet symptoms after prolonged near work, point to a binocular motor problem rather than a refractive error. Convergence insufficiency causes decompensated near exophoria that manifests as asthenopia and headache specifically after sustained near tasks. Hypermetropia and astigmatism reduce VA, which would improve with pinhole.

Incorrect. Angle-closure glaucoma causes acute severe pain, redness, nausea, and fixed mid-dilated pupil — not a chronic reading headache. Hypermetropia and astigmatism both reduce VA and improve with pinhole. Here, VA is normal and pinhole does not improve it, so a refractive mechanism is unlikely.

Correct. Bitot's spots (X1B) are pathognomonic of vitamin A deficiency: foamy, cheesy, triangular white-grey plaques on the temporal interpalpebral conjunctiva, non-wettable by tears. The cornea is still clear at this stage, distinguishing X1B from X2 onwards.

The WHO staging is: XN (night blindness) → X1A (conjunctival xerosis) → X1B (Bitot's spots — foamy, triangular, non-wettable plaques on temporal conjunctiva) → X2 (corneal xerosis, hazy cornea) → X3A (corneal ulcer <1/3 surface) → X3B (keratomalacia >1/3) → XS (corneal scar) → XF (xerophthalmic fundus). Foamy plaques on conjunctiva with clear corneas = X1B.

Incorrect. XN is pure night blindness with no visible lesion; X1A is conjunctival xerosis (dry, lusterless, non-foamy thickening); X1B specifically refers to Bitot's spots (foamy, cheesy plaques); X2 would show hazy, roughened cornea. The presence of foamy plaques on conjunctiva with clear corneas fits X1B exactly.

Correct. Intraocular malignancy = enucleation. The critical rule: NEVER eviscerate when there is any suspicion of intraocular tumour. A B-scan should exclude a mass before any evisceration, but in confirmed retinoblastoma, enucleation with long optic nerve stump is the standard of care.

Intraocular malignancy is the absolute indication for enucleation. Evisceration is absolutely contraindicated when intraocular malignancy is suspected because it leaves the sclera in situ and risks seeding tumour cells into the orbit. Exenteration is reserved for orbital extension of disease. Enucleation removes the entire globe plus a long optic nerve stump to achieve clear surgical margins.

Incorrect. Evisceration is contraindicated in intraocular malignancy because leaving the scleral shell risks orbital tumour spread. Exenteration would be excessive here — it is reserved for orbital extension or primary orbital malignancy. Option D is factually inverted: evisceration does NOT prevent sympathetic ophthalmia; enucleation of the offending eye is the prevention for SO.

Correct. Irrigation first — always. The rule: do not let history-taking, slit-lamp examination, or any other assessment delay irrigation in a chemical burn. Alkalis cause liquefactive necrosis, penetrate the anterior chamber, and damage the limbal stem cells; the damage continues until the pH is neutralised (target conjunctival pH 7.0-7.4).

Chemical burns — especially alkali — are the most time-critical ocular emergencies. Alkalis (NaOH, lime, ammonia) penetrate more deeply and rapidly than acids due to liquefactive necrosis, and continue to penetrate until the pH is neutralised. Irrigation must begin IMMEDIATELY without waiting for examination, history, or transport. Delay of even minutes worsens the prognosis.

Incorrect. No assessment, no pressure measurement, and no patching takes priority over immediate irrigation in a chemical burn. Delay = irreversible limbal stem cell destruction, corneal melt, and anterior chamber penetration. Begin copious irrigation with whatever safe fluid is available (saline preferred, water acceptable) and irrigate for a minimum of 30 minutes, then check pH.

Correct. Cataract is the leading cause of blindness in India (~66%), followed by refractive errors, corneal blindness, glaucoma, and posterior segment diseases. The high cataract burden despite available surgery is explained by access barriers, cost perception, quality concerns, and the cataract backlog — themes central to NPCBVI design.

Cataract remains the leading cause of blindness in India, accounting for approximately 66% of all blindness according to the India National Blindness and Visual Impairment Survey 2015-19. It is avoidable (treatable with surgery), which is why NPCBVI focuses heavily on cataract surgical rate (CSR) as its key performance indicator. Vision 2020 prioritised cataract as a primary target.

Incorrect. Globally, uncorrected refractive errors are the leading cause of vision impairment (but not blindness). In India, cataract leads both blindness and vision impairment. Glaucoma, diabetic retinopathy, and corneal blindness together account for a much smaller proportion than cataract (~66%).

Correct. Painful, pupil-involved CN III palsy = PCoA aneurysm until proven otherwise. Urgent CT/MRI angiography (CTA or MRA) is the investigation of choice — do not wait. Diabetic mononeuropathy causes pupil-sparing CN III palsy because ischaemia spares the superficial pupillomotor fibres.

A painful CN III palsy with a dilated fixed (pupil-involved) pupil must be treated as a posterior communicating artery (PCoA) aneurysm until proven otherwise — this is a neurosurgical emergency. The pupillomotor fibres travel on the outer surface of CN III and are compressed early by a PCoA aneurysm. Diabetic ischaemic CN III palsies classically SPARE the pupil because the ischaemia affects the central fibres while the superficial pupillomotor fibres are relatively preserved.

Incorrect. A pupil-SPARING CN III palsy in a known diabetic suggests ischaemic mononeuropathy (safe to monitor). A pupil-INVOLVED CN III palsy with pain is a red flag for PCoA aneurysm — a life-threatening neurosurgical emergency. Glucose and a 2-week follow-up are dangerously inadequate. Urgent neuroimaging (CTA/MRA) must not be delayed.

Correct. Blind, painful, phthisical eye + B-scan showing no tumour = evisceration. The scleral shell preservation offers better socket volume and movement for the prosthesis. The critical prerequisite — B-scan to exclude occult intraocular malignancy — has been fulfilled.

Evisceration is the procedure of choice for a blind painful eye (phthisis or endophthalmitis) when B-scan has excluded an intraocular tumour. It preserves the scleral shell and Tenon's capsule, giving better cosmetic and prosthetic results than enucleation. The mandatory B-scan rule: never eviscerate without first doing a B-scan to exclude a solid mass.

Incorrect. Enucleation removes the entire globe and is reserved for intraocular malignancy, sympathetic ophthalmia risk, or when evisceration is technically impossible. Exenteration removes the entire orbital contents and is for orbital malignancy or mucormycosis. Conservative management is inadequate for a chronically painful blind eye unresponsive to medical therapy.

Correct. WHO ICD-11 blindness = VA <3/60 OR visual field <10 degrees in the better eye with best correction. Note: India's NPCBVI operational criterion is less strict (<6/60) for field surveys. VA <6/18 = moderate impairment; VA <3/60 = blindness; VA <6/60 = severe impairment (WHO ICD-11).

WHO ICD-11 (2018) blindness criterion: VA <3/60 (or equivalent) in the better eye with best correction, OR visual field of less than 10 degrees around fixation in the better eye. India's NPCBVI uses an operational definition of VA <6/60 in the better eye for programme purposes. VA <6/18 is the threshold for moderate visual impairment.

Incorrect. VA <6/60 is the WHO ICD-11 category for severe visual impairment, not blindness. VA <3/60 OR field <10 degrees is the blindness threshold. VA <1/60 would be a stricter criterion not used in WHO ICD-11. VA <6/18 is moderate impairment. Know these thresholds precisely as they appear frequently in examinations.

Correct. Full correction of the deviation with the full hypermetropic prescription confirms fully accommodative esotropia. The key teaching point: prescribe the full cycloplegic refraction and reassess — this is both the diagnostic test and the treatment. Amblyopia must still be assessed and treated if present.

Fully accommodative esotropia is the most important refractive-related strabismus: hypermetropia drives excess accommodation, which drives excess convergence via the AC/A reflex, causing esotropia. The deviation is fully corrected by the full hypermetropic correction — the diagnostic and therapeutic test in one. Infantile esotropia is not corrected by glasses alone.

Incorrect. Infantile esotropia presents before 6 months, has a large angle not corrected by glasses alone, and requires surgery. CN VI palsy causes abduction failure with horizontal diplopia, not esotropia that corrects with glasses. Intermittent exotropia is an outward deviation. Spectacle correction of the full esotropia confirms the accommodative mechanism.

Correct. Hyphaema = blood-fluid level in the anterior chamber after blunt trauma. First-line management: rest with head elevation, topical steroids + cycloplegia, avoid antiplatelet agents (secondary bleed risk), monitor IOP, and refer to ophthalmology. Surgical washout is a last resort.

A blood-fluid level in the anterior chamber after blunt trauma is a hyphaema — a collection of blood between the cornea and iris. Immediate management: rest with head elevated 30-45 degrees (allows blood to settle and absorb), topical steroids, cycloplegics for comfort, avoid aspirin/NSAIDs (risk of secondary haemorrhage), and refer. Surgery (washout) is reserved for raised IOP unresponsive to medication or a total 8-ball hyphaema after 5 days.

Incorrect. Vitreous haemorrhage is behind the lens and not visible as a fluid level in the anterior chamber. Commotio retinae is a posterior segment finding (white retinal oedema) with no anterior chamber blood. The visible blood-fluid level in the anterior chamber = hyphaema. Conservative management (bed rest, head elevation, avoid NSAIDs) is first-line; immediate surgery is not.