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OP3.1-7 | Conjunctiva and Red Eye — Graded Quiz
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A 32-year-old software engineer presents with a red left eye. He reports the eye is sticky with yellow discharge that seals shut overnight, and a gritty sensation. There is no preauricular lymphadenopathy. Eversion of the upper lid shows flat, velvety, polygonal elevations (papillae) on the tarsal conjunctiva. Vision is 6/6 in both eyes. Which topical antibiotic is most appropriate as first-line empiric therapy?
Correct. Empiric topical chloramphenicol is first-line for uncomplicated acute bacterial conjunctivitis. It covers the common Gram-positive and Gram-negative organisms (Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae). Alternatives include topical fluoroquinolones or fusidic acid.
Acute bacterial conjunctivitis with mucopurulent discharge and papillary reaction (no preauricular node) is treated empirically with a broad-spectrum topical antibiotic such as chloramphenicol. Acyclovir targets viral (herpetic) disease; cromoglicate is for allergy; corticosteroids alone are contraindicated in bacterial infection.
Incorrect. The clinical features — mucopurulent discharge, papillary reaction, no preauricular node, 6/6 vision — confirm acute bacterial conjunctivitis. The correct empiric treatment is a broad-spectrum topical antibiotic. Acyclovir is for herpetic disease; cromoglicate is a mast-cell stabiliser for allergy; corticosteroids monotherapy is contraindicated in active bacterial infection.
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During a trachoma survey in a peri-urban community using the WHO simplified grading, a health worker finds a 45-year-old woman with conjunctival scarring (white fibrous bands on upper tarsal conjunctiva) but no active follicles, no trichiasis, and no corneal opacity. Which WHO trachoma grade applies?
Correct. TS = Trachomatous Scarring: easily visible white fibrous bands or sheets on the tarsal conjunctiva without active follicles or intense inflammation. The five WHO grades are TF (follicular), TI (intense), TS (scarring), TT (trichiasis), and CO (corneal opacity). Each grade is graded independently — they can coexist.
TS (Trachomatous Scarring) is the WHO grade for easily visible white fibrous bands or sheets on the upper tarsal conjunctiva in the absence of active inflammation. It indicates past trachoma; it is not itself an indication for antibiotic treatment but is an indicator of prior disease burden at community level.
Incorrect. Review the WHO simplified trachoma grading: TF = five or more follicles each 0.5 mm on upper tarsal conjunctiva; TI = intense inflammation obscuring over half the deep tarsal vessels; TS = white fibrous scarring on tarsal conjunctiva; TT = at least one lash touching the eyeball; CO = corneal opacity over the pupil. White fibrous bands without active inflammation = TS.
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A 12-year-old boy with known vernal keratoconjunctivitis presents acutely with intense pain, photophobia, and reduced vision in the right eye. On slit-lamp examination you find an oval epithelial defect in the superior cornea with an underlying grayish infiltrate and rolled edges. What complication of VKC does this represent?
Correct. The vernal shield (plaque) ulcer is an oval superior corneal ulcer with rolled edges and a grey eosinophilic plaque in the base. It results from giant papillae mechanically abrading the cornea combined with eosinophil-derived major basic protein deposition. It is the most serious corneal complication of VKC and requires specialist management, often including surgical debridement.
The vernal shield ulcer (plaque ulcer) is a characteristic and potentially sight-threatening complication of VKC, caused by mechanical trauma from giant tarsal papillae abrading the superior corneal epithelium, followed by eosinophil-derived toxic protein deposition in the ulcer bed, which prevents re-epithelialisation.
Incorrect. Corneal pannus is a vascular/fibrous ingrowth at the superior limbus, not an acute ulcer. A dendritic ulcer has a branching (dendritic) pattern on fluorescein staining with terminal bulbs. A corneal abrasion from a foreign body would reveal the FB on eversion. The superior oval corneal ulcer with rolled edges and grayish plaque in a VKC patient is the classic shield ulcer.
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A pterygium extending across the limbus is found to stop 3 mm from the pupillary margin. The patient is asymptomatic. Which of the following represents the strongest indication for surgical excision of this pterygium?
Correct. Induced astigmatism with reduced BCVA is a strong functional indication for pterygium excision. Even if the pterygium is not yet in the visual axis, corneal distortion from the fibrovascular growth can cause irregular astigmatism that cannot be fully corrected with spectacles. Surgery should be recommended in this scenario.
The accepted indications for pterygium surgery are: (1) visual axis encroachment, (2) induced irregular astigmatism causing reduced best corrected visual acuity, (3) restricted ocular motility, (4) failure of conservative measures for symptoms, and (5) documented progressive growth. Cosmetic concern alone is a relative indication and should be weighed against the risk of recurrence from surgery.
Incorrect. Surgery is not required for cosmetic concern alone (high recurrence risk), for a stable non-progressing pterygium, or for minor discomfort from drops. The accepted functional indications are visual axis encroachment, induced astigmatism reducing BCVA, and restricted ocular motility. A pterygium causing induced astigmatism and reduced BCVA meets a surgical threshold regardless of its distance from the pupil.
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A nurse is teaching patients how to instil eye drops. She asks a patient to instil one drop of timolol into the inferior conjunctival fornix, then immediately press the inner corner of the eye with a fingertip for one minute. What is the PRIMARY pharmacological rationale for pressing the medial canthus after drop instillation?
Correct. Nasolacrimal occlusion reduces the drainage of topical medication through the nasolacrimal system into the nasopharyngeal mucosa, which has high systemic bioavailability. For drugs with significant systemic effects (timolol, latanoprost, brimonidine), this manoeuvre reduces systemic side effects and improves local drug residence time.
Nasolacrimal occlusion (pressing the medial canthus over the lacrimal punctum) for 60 seconds reduces drainage of the drug into the nasolacrimal duct and nasopharynx, thereby reducing systemic absorption and its associated side effects (e.g., timolol-induced bradycardia, bronchospasm), and improving ocular bioavailability.
Incorrect. While nasolacrimal occlusion does incidentally prevent overflow, its PRIMARY pharmacological purpose is to block the nasolacrimal drainage pathway, thereby reducing systemic absorption of the drug through the nasal mucosa. For timolol, this reduces the risk of bradycardia and bronchospasm from systemic beta-blockade.
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A 7-year-old child is brought by his mother with a complaint of something in his right eye after playing outside. He has vertical linear corneal scratches visible on fluorescein staining. Where should you look for the foreign body?
Correct. Vertical linear corneal abrasions on fluorescein staining indicate a subtarsal foreign body (in the subtarsal groove of the upper eyelid). Each blink causes the FB to scratch the corneal epithelium vertically. The management is upper lid eversion followed by removal with a moistened cotton bud under topical anaesthesia.
Vertical linear corneal scratches (linear corneal abrasions visible on fluorescein staining) are the pathognomonic sign of a subtarsal foreign body. The FB lodges in the subtarsal groove on the inner surface of the upper eyelid and scratches the cornea with each blink, producing the characteristic linear pattern. Upper lid eversion is essential to locate it.
Incorrect. The key diagnostic clue here is the pattern of corneal staining: vertical linear scratches are produced by a foreign body lodged in the subtarsal groove of the upper eyelid, scraping the cornea with each blink. If the FB were on the bulbar conjunctiva or in the inferior fornix, you would not see this pattern of linear vertical abrasions. Always evert the upper lid when you see this staining pattern.
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A 30-year-old man from an area hyper-endemic for trachoma has developed progressive inward turning of three eyelashes of the upper lid, which intermittently touch his cornea. The cornea shows a grade 3 opacity covering part of the pupil. On the WHO scale, which two trachoma grades should be recorded?
Correct. TT (Trichiasis) is defined as at least one eyelash touching the eyeball; CO is a corneal opacity easily visible over the pupil. Both indicate late/blinding trachoma. Surgical correction of trichiasis (SAFE strategy S component) is the priority to prevent further corneal scarring.
TT (Trachomatous Trichiasis) = at least one eyelash rubbing the eyeball or evidence of recent eyelash removal. CO (Corneal Opacity) = easily visible corneal opacity over the pupil. These two grades represent late, blinding trachoma. WHO grades are not mutually exclusive — multiple grades can coexist.
Incorrect. The five WHO trachoma grades are TF, TI, TS, TT, and CO. Eyelashes touching the cornea = TT (Trichiasis). Corneal opacity over the pupil = CO (Corneal Opacity). These grades can coexist; you record all applicable grades. TF and TI indicate active inflammation; TS indicates scarring (fibrous bands on tarsal conjunctiva).
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A patient presents to a primary care clinic with a red eye and the following features: onset 1 week ago, unilateral, photophobia, aching periocular pain (not gritty), ciliary flush, no discharge, and vision of 6/18 in the affected eye. Which diagnosis is MOST CONSISTENT with this presentation and what is the priority management?
Correct. Anterior uveitis is characterised by photophobia, aching periocular pain, ciliary (circumcorneal) injection, reduced VA, and the absence of discharge. It is a sight-threatening condition requiring urgent slit-lamp assessment, cycloplegia (e.g., cyclopentolate), and topical corticosteroids to prevent posterior synechiae and secondary glaucoma.
Anterior uveitis presents with photophobia, aching pain (from ciliary muscle spasm), ciliary flush, reduced vision, and no discharge. It requires urgent ophthalmology referral for slit-lamp confirmation (keratic precipitates, cells/flare), cycloplegia (to relieve ciliary spasm and prevent posterior synechiae), and topical corticosteroids.
Incorrect. Conjunctivitis does not reduce vision. Episcleritis causes a sectoral redness without photophobia or reduced VA. Subconjunctival haemorrhage is painless with normal vision and no discharge. The combination of photophobia, aching periocular pain, ciliary injection, and reduced VA without discharge is the clinical signature of anterior uveitis — a red-eye emergency requiring specialist referral, not primary care management.
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A 55-year-old farmer from Rajasthan presents with bilateral slowly progressive red eyes, intense photophobia, tearing, and a yellowish-white nodule at the limbus. He has no prior history of infection. Corneal involvement is present superiorly. What is the MOST LIKELY diagnosis?
Correct. Phlyctenular keratoconjunctivitis is a classic chronic conjunctivitis aetiology in India and Africa, most often representing a delayed hypersensitivity response to Mycobacterium tuberculosis proteins (in TB-endemic populations) or staphylococcal antigens. The limbal phlycten (yellowish-white nodule) with photophobia and possible corneal involvement is the hallmark. Treatment targets the underlying cause (anti-tubercular or anti-staphylococcal) plus topical corticosteroids.
Phlyctenular keratoconjunctivitis is a Type IV (delayed hypersensitivity) reaction to microbial antigens (classically Mycobacterium tuberculosis in TB-endemic areas, or Staphylococcus aureus in other settings). It presents with a yellowish-white limbal nodule (phlyctens), intense photophobia, tearing, and, when the cornea is involved, severe pain. It must be differentiated from VKC (which causes itch and giant papillae, not a limbal nodule) and pterygium.
Incorrect. VKC occurs in younger males with giant tarsal papillae and seasonal itch, not a limbal nodule. Mooren's ulcer is a peripheral ulcerative keratitis, not a nodule. Pterygium is a fibrovascular growth, not a nodular lesion. The limbal yellowish-white nodule with intense photophobia in a middle-aged adult from a TB-endemic area is the hallmark of phlyctenular keratoconjunctivitis — a chronic conjunctivitis aetiology caused by Type IV hypersensitivity to microbial antigens.
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