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

Correct. The principle is treat amblyopia first, align the eyes after. Step 1: prescribe glasses and see if the deviation is partly accommodative. Step 2: occlude the sound eye to drive the amblyopic eye. Step 3: surgical correction once VA gap is minimised. Botulinum toxin is used in some cases but is not the primary definitive treatment for this scenario.

The management sequence for comitant strabismus with amblyopia is: (1) prescribe any refractive error correction and assess whether the deviation is accommodative, (2) treat amblyopia with occlusion of the better eye, (3) plan surgical alignment once amblyopia is maximally treated. Operating before treating amblyopia risks amblyopia worsening post-operatively due to reduced visual competition.

Incorrect. Surgery before amblyopia treatment is the most common management error in paediatric strabismus. Aligning the eyes in a child who still has dense amblyopia does not improve VA — the brain continues to suppress the amblyopic eye. The correct sequence: refraction → occlusion therapy → surgery.

Correct. Corneal melt >1/3 of surface = X3B (keratomalacia). The WHO high-dose protocol: 200,000 IU oral vitamin A on Day 1, Day 2, and 2 weeks later (3 doses total). For children <1 year or <8 kg, halve the dose to 100,000 IU. This child is likely >1 year at age 2 — use the 200,000 IU schedule.

WHO xerophthalmia staging: XN → X1A → X1B → X2 (corneal xerosis, hazy cornea) → X3A (corneal ulcer/necrosis <1/3 surface) → X3B (keratomalacia >1/3 surface — the most severe active stage, implies full melt and collapse) → XS (scar) → XF (fundus). A collapsed anterior chamber + corneal melt >half the surface = X3B. WHO protocol for severe cases (X3A, X3B): 200,000 IU (children >1 yr) on day 1, day 2, and at 2 weeks.

Incorrect. Review the WHO xerophthalmia staging order: XN → X1A → X1B → X2 → X3A → X3B → XS → XF. Corneal melt covering >1/3 of the surface with a collapsed anterior chamber = X3B, the most severe active stage. Stage X2 is mild corneal haze without ulceration. Stage XS is a healed scar. The correct WHO dose for X3A/X3B is 200,000 IU on 3 occasions (day 1, day 2, 2 weeks).

Correct. Open globe injury management: Fox shield (rigid, non-compressive), nil by mouth (patient needs surgery), IV antibiotics if available, urgent transfer for primary repair. No pressure on the eye. Irrigation is specifically for chemical burns — it is contraindicated with open globe injuries as it can extrude intraocular contents.

A full-thickness corneal laceration with iris prolapse = open globe injury. Immediate management: place a rigid Fox shield (not a pad — pressure can extrude intraocular contents), ensure nil by mouth, give systemic antiemetics, give IV antibiotics if available, and arrange urgent transfer to a tertiary eye centre for primary surgical repair. NEVER irrigate, NEVER apply topical drops that require pressure, NEVER patch with pressure.

Incorrect. Irrigation is the correct first step for CHEMICAL BURNS, not for open globe mechanical injuries. Applying pressure (either a tight pad or pressing in drops) can extrude vitreous, iris, or lens through the wound. A Fox shield protects without contact. Do not defer to the next day — open globe injuries are surgical emergencies (goal: repair within 24 hours to minimise endophthalmitis risk).

Correct. Myopes who remove their distance glasses to read have their near focus naturally, but this creates a vergence-accommodation mismatch over sustained periods. The correct advice: wear the distance correction plus use near add if needed for reading (bifocals/progressives). Distance VA is normal with correction, confirming adequate correction at distance.

Myopes can read without glasses by using their natural myopic focal point. However, removing distance glasses for reading dissociates accommodation from convergence — the eyes converge for near but do not accommodate (the near-object is already in focus without effort), disrupting the normal AC/A link and causing asthenopia from vergence-accommodation mismatch in sustained near tasks.

Incorrect. Myopes do NOT strain accommodatively at distance with their correction — if VA is 6/6 with glasses, the prescription is adequate. Presbyopia begins after 40 and is a consideration, but the core mechanism here is vergence-accommodation dissociation from removing glasses at near. Myopic fundus changes cause visual symptoms but not a typical end-of-day work-related headache pattern.

Correct. NPCB launched 1976. CSR (cataract operations per million per year) is the key performance indicator for the cataract component. Vision 2020 (launched 1999 globally; adopted by India) added the international framework but the programme itself began in 1976.

NPCB was launched in India in 1976 — one of the earliest national blindness control programmes globally. It was renamed NPCBVI (adding Visual Impairment) to reflect the broader mandate. The Cataract Surgical Rate (CSR) — operations per million population per year — is the primary indicator used to track cataract programme output. India's target CSR under Vision 2020 was 4,000/million; the current achieved CSR is approximately 5,000-6,000/million though quality outcomes remain variable.

Incorrect. The programme was launched in 1976, not 1990 or 1999. Vision 2020 was a global initiative launched in 1999 by WHO and IAPB, which India adopted, but the national programme predated it by 23 years. Trachoma elimination is a target under Vision 2020 globally but is not the primary NPCBVI performance indicator.

Correct. Alkali = liquefactive necrosis = unlimited penetration until pH is normalised = WORSE than acid. The coagulative barrier formed by acid burns actually limits penetration — this is why alkali is more dangerous. Calcium hydroxide (lime) and sodium hydroxide are particularly damaging. Immediate copious irrigation is the single most important intervention.

ALKALI BURNS ARE WORSE THAN ACID BURNS — this is a critical domain fact. Alkalis (NaOH, Ca(OH)2 lime, NH3 ammonia) cause liquefactive necrosis: they saponify fatty acids in cell membranes, penetrate through the cornea into the anterior chamber, and continue to cause damage until the pH is neutralised. Acids cause coagulative necrosis — the precipitated protein forms a barrier that limits penetration. Irrigation must start IMMEDIATELY for alkali and continue until conjunctival pH 7.0-7.4.

Incorrect. The correct teaching is the opposite: ALKALI burns are worse than acid burns. Acids cause coagulative necrosis with a self-limiting protein barrier. Alkalis cause liquefactive necrosis — there is NO self-limiting barrier — and they penetrate into the anterior chamber, damaging the lens, trabecular meshwork, and ciliary body. Option D describes acid burns, not alkali.

Correct. Sympathetic ophthalmia risk (penetrating trauma + fellow eye changes) = enucleation, not evisceration. Evisceration leaves the uveal tissue (the antigenic trigger) inside the scleral shell, which can perpetuate the autoimmune uveal response in the fellow eye. B-scan excludes a solid mass, so the sole contraindication to evisceration is the SO risk — which mandates enucleation.

The history of penetrating trauma 30 years ago with recent visual changes in the fellow eye raises the clinical concern for sympathetic ophthalmia — a bilateral panuveitis triggered by penetrating injury to one eye. The only way to prevent progression of sympathetic ophthalmia is enucleation of the injured (exciting) eye within 2 weeks of injury; late enucleation may still arrest progression. Evisceration is CONTRAINDICATED when sympathetic ophthalmia risk exists because it leaves uveal tissue behind.

Incorrect. Evisceration is contraindicated when sympathetic ophthalmia is a concern because it retains the uveal tissue responsible for triggering the bilateral autoimmune reaction. Exenteration is reserved for orbital malignancy or mucormycosis — not for sympathetic ophthalmia. Conservative management cannot address the sympathetic ophthalmia risk to the fellow eye.

Correct. Right CN IV (superior oblique) palsy: right hypertropia worse in left gaze (SO acts in adduction) and worse on right head tilt (Parks-Bielschowsky 3-step test). Patients adopt a compensatory left head tilt to reduce diplopia. The vertical diplopia worse on downgaze and stair-descent is the classic symptom.

CN IV supplies the superior oblique, which intorts the eye and depresses it in adduction. A right CN IV palsy causes a right hypertropia (the right eye rides high because the depressor SO is weak). The Parks-Bielschowsky 3-step test: Step 1 — which eye is higher? (right = right SO or left IR weak). Step 2 — worse on which side gaze? (left gaze = right SO field). Step 3 — head tilt? (right tilt = worse if right SO weak). All 3 positive = right CN IV palsy.

Incorrect. CN IV palsy causes hypertropia (affected eye elevated) not hypotropia. CN VI palsy causes esotropia with abduction limitation. CN III palsy causes exotropia with ptosis and dilated pupil (plus limitation of all other movements). The correct pattern for right CN IV palsy is right hypertropia, worst on left gaze and right head tilt (Parks-Bielschowsky).

Correct. Clinical diagnosis is sufficient — do not delay for blood tests. X2/X3 cases need the emergency WHO three-dose schedule immediately; XN and X1B cases should receive supplementation at PHC level. The national programme distributes 200,000 IU every 6 months to all children 1-5 years in high-risk areas as prevention.

Xerophthalmia is a clinical diagnosis. Treatment must not be delayed for laboratory confirmation when clinical signs are present. WHO and India's National Vitamin A Supplementation Programme protocol: corneal involvement (X2, X3A, X3B) = high-dose WHO emergency schedule (200,000 IU on days 1, 2, and 14 for children >1 yr). Night blindness (XN) and Bitot's spots (X1B) = supplementation dose at PHC level without referral. All malnourished children in an endemic area should be treated empirically.

Incorrect. Serum retinol levels are not required before treatment when clinical signs are present — delay risks irreversible corneal damage. Night blindness (XN) and Bitot's spots (X1B) also require supplementation: these early stages are preventable progression to corneal blindness. Dietary counselling alone is insufficient for active xerophthalmia.

Correct. The cataract backlog is a demand-side problem, not a supply-side problem. Surgery is available free of charge at district hospitals under NPCBVI, yet uptake remains suboptimal due to access and behavioural barriers. Understanding these barriers is essential for a PHC doctor to actively mobilise patients rather than waiting for them to present.

The cataract backlog in India persists not due to lack of surgical provision but due to demand-side barriers: fear of surgery (especially blindness), lack of transportation, need for an escort, cost of travel and lost wages, poor awareness, quality perception concerns (patient has heard of poor outcomes), and cultural fatalism. NPCBVI programmes address these through outreach camps, community mobilisation, and free transport schemes. Cataract is the FIRST priority disease under Vision 2020.

Incorrect. Cataract surgery IS available at district hospital level under NPCBVI. Cataract IS included as the primary disease in Vision 2020. The programme does fund cataract surgery — it is a cornerstone of NPCBVI. The correct explanation is demand-side barriers (fear, access, transport, quality perception) that prevent patients from accepting available free surgery.