Final Professional MBBS — Ophthalmology (complete, 12 chapters). Explanation-first answers with anatomical, optics, neuro & public-health diagrams, classifications, comparison tables, drug doses, clinical pearls and key-point recaps from Khurana's Comprehensive Ophthalmology, Parsons' Diseases of the Eye and Park's PSM.
12chapters144questions39High-Yield
THE CONCEPT
Conjunctivitis is inflammation of the conjunctiva — the transparent membrane covering the white of the eye and the inner lids. It is the commonest eye disease, and the single most useful idea to grasp is that it is a 'red eye without pain, photophobia or loss of vision' — features that separate it from the dangerous causes of a red eye (keratitis, uveitis, acute glaucoma). Its causes are broadly infective (bacterial, viral, chlamydial) and allergic.
SYMPTOMS
The patient typically has redness, discharge, a gritty or foreign-body sensation, watering, and sticking of the lids (worse on waking). Crucially, there is no significant ocular pain, no true photophobia, and vision is essentially normal (any blurring clears on blinking away the discharge). The type of discharge is a valuable clue to the cause.
Follicles; trachoma and adult inclusion conjunctivitis
SIGNS
The redness of conjunctivitis is a superficial 'conjunctival' congestion — brightest in the fornices, moving with the conjunctiva, and blanching with topical adrenaline — in contrast to the deep ciliary congestion (around the cornea) of keratitis/uveitis. Other signs are follicles (viral, chlamydial), papillae (bacterial, allergic), a preauricular node (viral), and the discharge itself.
Conjunctival congestion
Superficial · peripheral / fornix
Brick-red · blanches with adrenaline
→ conjunctivitis
Ciliary congestion
Deep · circumcorneal (limbal)
Violaceous · does NOT blanch
→ keratitis / uveitis / glaucoma
Distinguishing the two patterns of red eye: superficial conjunctival congestion (peripheral, blanches with adrenaline) versus deep ciliary/circumcorneal congestion (around the limbus, does not blanch).
MANAGEMENT
General — strict hygiene (most infective types are contagious).
Bacterial — topical antibiotics (chloramphenicol or a fluoroquinolone); most are self-limiting.
Viral — supportive (cold compresses, lubricants, hygiene); it is self-limiting, and steroids are avoided unless there is specific corneal involvement under supervision.
Allergic — antihistamines and mast-cell stabilisers, and avoiding the allergen.
Gonococcal (hyperacute) — an emergency (risk of corneal perforation) needing systemic and topical antibiotics.
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CLINICAL PEARL: The defining rule: conjunctivitis is a red eye WITHOUT pain, photophobia or visual loss — if any of these are present, think keratitis, uveitis or acute glaucoma instead. Use the discharge to identify the cause: purulent = bacterial, watery + follicles + preauricular node = viral, itching + ropey = allergic. A hyperacute purulent conjunctivitis is gonococcal and an emergency.
CONJUNCTIVAL VS CILIARY CONGESTION
A fundamental skill in assessing any red eye is distinguishing the two patterns of redness, because it separates a benign conjunctivitis from a sight-threatening problem. Conjunctival (superficial) congestion is brick-red, most marked in the fornices and fading toward the cornea, moves when the conjunctiva is moved, and blanches with topical adrenaline — typical of conjunctivitis. Ciliary (deep) congestion is a violaceous, radial flush maximal around the corneal margin (the limbus), does not move, and does not blanch with adrenaline — indicating keratitis, iridocyclitis (uveitis) or acute glaucoma. Reading this correctly directs the whole assessment.
FOLLICLES VS PAPILLAE
Two conjunctival reactions help identify the cause and are worth understanding. Follicles are rounded, pale, avascular lymphoid aggregates (vessels run over and around them), typical of viral and chlamydial conjunctivitis. Papillae are flat-topped, red, vascular projections with a central vascular core, typical of bacterial and allergic conjunctivitis, and become 'giant' (cobblestone) in vernal disease. Recognising follicles versus papillae on the tarsal conjunctiva is a classic examination point that narrows the differential.
GONOCOCCAL CONJUNCTIVITIS — AN EMERGENCY
The one form of bacterial conjunctivitis that must never be underestimated is hyperacute gonococcal (Neisseria gonorrhoeae) conjunctivitis. It develops rapidly with very copious ('gushing') purulent discharge, marked lid oedema and chemosis, and — critically — Neisseria can penetrate an intact cornea, causing rapid corneal ulceration and perforation. It is therefore a true emergency requiring urgent Gram stain, systemic and topical antibiotics, and frequent saline lavage, together with treatment of the sexual partner(s). It illustrates why the amount and speed of a purulent discharge matters.
A NOTE ON THE OPHTHALMIA NEONATORUM & CHLAMYDIAL OVERLAP
Two special forms of conjunctivitis link this topic to later chapters and deserve mention. Chlamydial conjunctivitis occurs both as trachoma (serotypes A–C) and as adult inclusion conjunctivitis (serotypes D–K, sexually transmitted), the latter a chronic follicular conjunctivitis needing systemic treatment and partner treatment. And any severe neonatal conjunctivitis is ophthalmia neonatorum, where a hyperacute purulent picture suggests gonococcus. Recognising when a 'simple' conjunctivitis is in fact chlamydial or gonococcal — and therefore needs systemic therapy and contact tracing — is an important safeguard against under-treatment.
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KEY POINTS / NUMBERS (viva)
Red eye WITHOUT pain/photophobia/visual loss = conjunctivitis (vs keratitis/uveitis/glaucoma, which have all three).
SOURCES: Khurana's Comprehensive Ophthalmology; Parsons' Diseases of the Eye.
THE CONCEPT
Trachoma is a chronic keratoconjunctivitis caused by Chlamydia trachomatis (serotypes A, B, Ba and C). It is of enormous public-health importance as the leading infective cause of preventable blindness worldwide. It spreads by contact, flies and fomites in conditions of poor hygiene, overcrowding and water scarcity, and causes blindness through years of repeated infection leading to scarring, in-turned lashes and corneal damage.
WHO SIMPLIFIED GRADING
The WHO grades trachoma into five signs, easily remembered as the sequence of the disease:
TF (Trachomatous inflammation – Follicular) — five or more follicles on the upper tarsal conjunctiva.
TI (Trachomatous inflammation – Intense) — pronounced inflammatory thickening that obscures the tarsal vessels.
TT (Trachomatous Trichiasis) — at least one in-turned lash touching the globe.
CO (Corneal Opacity) — the blinding end-stage.
CHARACTERISTIC SIGNS
Trachoma has several classic signs: follicles on the upper tarsal conjunctiva, papillae, a superior corneal pannus (fibrovascular invasion of the cornea from above), Herbert's pits (depressed scars from healed limbal follicles — pathognomonic), and Arlt's line (a linear tarsal scar). Progressive scarring causes entropion and trichiasis, which abrade the cornea to produce opacity and blindness.
COMPLICATIONS
The complications are largely those of cicatrisation (scarring): trichiasis, entropion, corneal opacity, dry eye (xerosis), ptosis, symblepharon, and ultimately blindness.
MANAGEMENT — THE 'SAFE' STRATEGY
The WHO control programme is summarised by the mnemonic SAFE:
S — Surgery for trichiasis/entropion (to stop lashes damaging the cornea).
A — Antibiotics — a single oral dose of azithromycin (or topical tetracycline) for active infection, often given as mass treatment.
F — Facial cleanliness (reduces transmission).
E — Environmental improvement (clean water, sanitation, fly control).
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CLINICAL PEARL: Key facts: trachoma is a chronic Chlamydia trachomatis (serotypes A, B, Ba, C) keratoconjunctivitis and the leading infective cause of preventable blindness. Herbert's pits are pathognomonic; other signs are Arlt's line and superior pannus. Control is by the WHO SAFE strategy (Surgery, Antibiotics – azithromycin, Facial cleanliness, Environmental improvement).
PATHOGENESIS — WHY REPEATED INFECTION BLINDS
Understanding trachoma's pathogenesis explains why it blinds so insidiously. A single episode of chlamydial infection causes a self-limiting follicular conjunctivitis, but in endemic areas repeated re-infection over years drives chronic inflammation and progressive subconjunctival scarring (cicatrisation). This scarring contracts the tarsal plate, turning the lid margin inward (entropion) so the lashes rub the cornea (trichiasis); the constant abrasion, compounded by dryness from destroyed goblet cells and tear glands, causes corneal opacification and blindness. The disease is thus a slow, cumulative consequence of chronic and repeated infection, not a single event.
THE ROLE OF MASS DRUG ADMINISTRATION
A key public-health element of the 'A' in SAFE is mass drug administration (MDA): in endemic districts, a single annual oral dose of azithromycin is given to the whole community (not just those with active disease), because so many people carry subclinical infection that acts as a reservoir. Treating the whole population repeatedly over several years interrupts transmission far more effectively than treating individuals. This community-wide approach, combined with hygiene and environmental measures, is what has driven trachoma toward elimination in many regions.
A NOTE ON THE MacCALLAN CLASSIFICATION
Alongside the WHO grading, the older MacCallan classification is often asked and describes the clinical course in four stages: Stage I (incipient — immature follicles), Stage II (established — mature follicles and papillae, with early pannus), Stage III (cicatricial — scarring begins, e.g. Arlt's line), and Stage IV (healed/sequelae — scarring with its complications such as trichiasis and entropion, but no active inflammation). This staging emphasises the progression from active inflammation to the blinding cicatricial sequelae, complementing the practical WHO signs.
A NOTE ON DIAGNOSIS & THE GLOBAL ELIMINATION EFFORT
Trachoma is largely a clinical diagnosis based on the WHO signs (particularly upper tarsal follicles and scarring), though laboratory confirmation of Chlamydia trachomatis (by PCR, or Giemsa staining showing intracytoplasmic inclusion bodies) is possible. Globally, trachoma is the target of a major WHO elimination programme using the SAFE strategy, and many previously endemic countries have eliminated it as a public-health problem. This success story underlines that trachoma blindness is entirely preventable through hygiene, antibiotics and lid surgery — a point often emphasised in community-ophthalmology answers.
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KEY POINTS / NUMBERS (viva)
Cause: Chlamydia trachomatis serotypes A, B, Ba, C; leading infective cause of preventable blindness.
WHO SAFE: Surgery (trichiasis), Antibiotics (single-dose azithromycin/topical tetracycline), Facial cleanliness, Environmental improvement.
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KEY POINTS TO REMEMBER
Trachoma = chronic keratoconjunctivitis from Chlamydia trachomatis (A, B, Ba, C); leading infective cause of preventable blindness; spread by contact/flies/fomites in poor hygiene.
WHO grading: TF, TI, TS, TT, CO (follicular → intense → scarring → trichiasis → corneal opacity).
Control by WHO SAFE strategy: Surgery (trichiasis), Antibiotics (single-dose azithromycin), Facial cleanliness, Environmental improvement.
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SOURCES: Khurana's Comprehensive Ophthalmology; WHO trachoma grading.
THE CONCEPT
Ophthalmia neonatorum is conjunctivitis occurring in a newborn within the first 28 days of life. It is important (and notifiable) because some forms — especially gonococcal — can rapidly cause corneal perforation and blindness. The infection is usually acquired from the mother's genital tract during birth, so its prevention and treatment also involve the mother.
Commonest infective cause now; mucopurulent; may have pneumonitis
Others (Staph, herpes simplex)
Day 5–7
HSV may be systemic/serious
CLINICAL FEATURES
There is lid oedema, conjunctival congestion, chemosis and discharge — the discharge being strikingly copious and purulent in gonococcal disease, which is the most dangerous form.
INVESTIGATION
A conjunctival swab and scraping are essential: Gram stain showing Gram-negative intracellular diplococci indicates gonococcus, culture confirms it, and chlamydial testing (PCR, or Giemsa stain showing intracytoplasmic inclusion bodies) identifies inclusion conjunctivitis.
MANAGEMENT & PROPHYLAXIS
Gonococcal — an emergency: systemic ceftriaxone plus topical antibiotics and frequent saline lavage; treat the mother and her partner.
Chlamydial — systemic oral erythromycin (also treats/prevents the associated pneumonitis) with topical treatment; treat the mother.
Prophylaxis at birth — historically Credé's method (silver nitrate); now topical antibiotic (erythromycin/tetracycline) or povidone-iodine, together with antenatal screening and treatment of the mother.
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CLINICAL PEARL: Timing distinguishes the causes: gonococcal (day 2–4, hyperacute, an emergency with perforation risk) versus chlamydial (day 5–14, now the commonest). A Gram stain guides treatment — systemic ceftriaxone for gonococcal, oral erythromycin for chlamydial — and one must always treat the mother and give prophylaxis at birth.
WHY GONOCOCCAL DISEASE IS SO DANGEROUS
The reason gonococcal ophthalmia neonatorum is treated as an emergency lies in the organism's behaviour: Neisseria gonorrhoeae can invade an intact corneal epithelium, so unlike most bacteria it does not need a pre-existing breach to damage the cornea. In the neonate this leads rapidly to corneal ulceration, perforation, endophthalmitis and permanent blindness if untreated. The very copious purulent discharge and tense lid oedema are the warning signs, and the speed of progression is why systemic treatment must begin without waiting for culture results.
A NOTE ON ASSOCIATED SYSTEMIC INFECTION
An important point is that neonatal conjunctivitis may be the visible sign of a wider infection. Chlamydial infection acquired at birth can also cause a neonatal pneumonitis a few weeks later, which is why chlamydial ophthalmia is treated with systemic (oral) erythromycin rather than topical treatment alone — to eradicate the organism from the nasopharynx and lungs. Similarly, herpes simplex conjunctivitis may herald disseminated or CNS herpes. Treating the eye alone would miss these serious systemic components.
PROPHYLAXIS & PREVENTION IN DEPTH
Prevention operates at several levels. Antenatal screening and treatment of maternal gonorrhoea and chlamydia removes the source; at birth, ocular prophylaxis (historically Credé's 1% silver nitrate, now topical erythromycin/tetracycline ointment or povidone-iodine) is instilled into both eyes; and postnatally, prompt recognition and treatment prevent complications. Because ophthalmia neonatorum is a notifiable, preventable cause of childhood blindness, this layered prophylaxis is a public-health priority.
A NOTE ON THE DIFFERENTIAL BY DISCHARGE & COURSE
In practice, alongside the timing, the character of the discharge and the clinical course help point to the cause of neonatal conjunctivitis. A hyperacute, copious, purulent discharge with tense lid oedema strongly suggests gonococcus and demands immediate action; a subacute mucopurulent discharge appearing at the end of the first week suggests chlamydia; and vesicular lid lesions with a serous discharge should raise the possibility of herpes simplex (with its risk of disseminated disease). This pattern recognition, confirmed by microbiology, guides prompt and correct treatment in a condition where delay can blind.
A NOTE ON THE PUBLIC-HEALTH IMPORTANCE
Ophthalmia neonatorum is a notifiable disease in many countries precisely because it is a preventable cause of childhood blindness, and its control is a public-health achievement. The dramatic fall in gonococcal blindness after the introduction of routine neonatal eye prophylaxis (Credé's method historically, now topical antibiotics/povidone-iodine) and antenatal maternal screening is a classic example of successful preventive ophthalmology. This is why every case is treated seriously, the source (the mother) is always investigated and treated, and prophylaxis is a routine part of newborn care.
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KEY POINTS / NUMBERS (viva)
Onset timing: chemical day 1, gonococcal day 2–4 (hyperacute/emergency), chlamydial day 5–14 (commonest).
Gram stain: Gram-negative intracellular diplococci = gonococcus; Giemsa/PCR for chlamydia.
Gonococcal → systemic ceftriaxone + topical + lavage; chlamydial → oral erythromycin; treat the mother; prophylaxis at birth.
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KEY POINTS TO REMEMBER
Ophthalmia neonatorum = conjunctivitis in the first 28 days; notifiable; can blind (gonococcal); acquired from the birth canal.
SOURCES: Khurana's Comprehensive Ophthalmology; Parsons' Diseases of the Eye.
THE CONCEPT
Vernal keratoconjunctivitis (VKC), or 'spring catarrh', is a chronic, bilateral, allergic inflammation of the conjunctiva mediated by Type I and Type IV hypersensitivity. It is characteristically recurrent and seasonal (worse in spring and summer, and in warm, dry climates), affects young boys, and is often associated with a personal or family history of atopy. Its hallmark symptom is intense itching.
CLINICAL TYPES
Palpebral — giant, flat-topped 'cobblestone' papillae on the upper tarsal conjunctiva.
Bulbar (limbal) — gelatinous thickening at the limbus with Horner–Trantas dots (small white spots of degenerated eosinophils at the limbus).
Mixed — features of both.
SYMPTOMS & SIGNS
The dominant symptom is intense itching, with photophobia, watering, a stringy/ropey mucoid discharge, and a foreign-body sensation. Signs include the cobblestone papillae, Horner–Trantas dots, limbal thickening, and a 'shield ulcer' (a sterile epithelial ulcer of the upper cornea from the mechanical and inflammatory effect of the papillae).
MANAGEMENT
General — avoid allergens, cold compresses, dark glasses, and a cooler environment.
Mast-cell stabilisers (sodium cromoglicate), antihistamines, and dual-action agents (olopatadine) for prevention and control.
Topical corticosteroids — a short course for severe exacerbations, used cautiously (risk of steroid-induced glaucoma and cataract).
Topical cyclosporine — as a steroid-sparing agent in severe/chronic disease.
Reassuringly, VKC is usually self-limiting and tends to resolve around puberty.
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CLINICAL PEARL: Recognise VKC as the young boy with bilateral, seasonal, intensely itchy eyes showing cobblestone papillae on the upper tarsus, Horner–Trantas dots, a shield ulcer and ropey discharge. Treat with mast-cell stabilisers/antihistamines, short careful courses of steroids, and cyclosporine for severe cases; it usually resolves by puberty.
PATHOPHYSIOLOGY — TWO HYPERSENSITIVITY MECHANISMS
VKC is driven by a combination of Type I (immediate, IgE-mediated) and Type IV (delayed, cell-mediated) hypersensitivity. The Type I component (mast-cell degranulation releasing histamine) explains the intense itching, watering and immediate redness on allergen exposure, while the Type IV component drives the chronic eosinophil-rich inflammation, giant papillae and tissue remodelling. This dual mechanism is why treatment combines mast-cell stabilisers/antihistamines (targeting Type I) with anti-inflammatory agents such as steroids and cyclosporine (targeting the chronic Type IV inflammation).
THE SHIELD ULCER
The most sight-threatening feature of VKC is the shield ulcer — a sterile, oval epithelial ulcer of the upper cornea, so named for its shape. It arises from a combination of the mechanical trauma of the giant papillae rubbing the cornea and the toxic effect of eosinophil-derived proteins on the epithelium. A plaque of mucus and debris can settle in its base, delaying healing. Because it threatens vision, a shield ulcer indicates the need for more intensive treatment (steroids, and removal of the plaque) and careful monitoring.
A NOTE ON THE RISKS OF STEROID THERAPY
Because VKC is chronic and recurrent, and steroids are so effective, there is a real danger of prolonged or unsupervised topical steroid use, which can cause steroid-induced glaucoma, posterior subcapsular cataract, and increased susceptibility to infection (including herpes simplex keratitis). This is why steroids are used in short, tapering courses for exacerbations only, why intraocular pressure is monitored, and why steroid-sparing agents (mast-cell stabilisers, cyclosporine) are preferred for long-term control. It is a classic example of balancing efficacy against the hazards of chronic steroid use.
A NOTE ON THE PROGNOSIS & COURSE
An important reassurance in VKC is its natural history: although it is troublesome and recurrent through childhood, it is usually self-limiting and tends to 'burn out' around puberty, so the goal of treatment is to control symptoms and protect the cornea through the active years rather than to achieve a permanent cure. A minority progress to a chronic adult form (atopic keratoconjunctivitis) or develop lasting complications such as corneal scarring, keratoconus or steroid-induced problems. Setting these expectations helps families understand why long-term, steroid-sparing control is preferred over repeated courses of strong steroids.
A NOTE ON THE DIFFERENTIAL & ATOPIC KC
VKC should be distinguished from other allergic eye diseases. Simple allergic (seasonal) conjunctivitis is milder, with itching and papillae but no giant papillae or corneal involvement. Atopic keratoconjunctivitis (AKC) is the chronic adult counterpart, occurring in patients with atopic dermatitis, affecting the lower tarsus more, and carrying a higher risk of scarring, cataract and keratoconus. Recognising VKC as the childhood, upper-tarsal, seasonal, self-limiting form — as opposed to the persistent adult AKC — guides both prognosis and the intensity of long-term treatment.
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KEY POINTS / NUMBERS (viva)
VKC/spring catarrh: bilateral, seasonal (spring/summer), young boys, atopic; Type I + IV hypersensitivity; hallmark = intense itching.
Avoid allergen/cold compress + mast-cell stabilisers/antihistamines; short cautious steroids (glaucoma/cataract); cyclosporine for severe.
Usually self-limiting, resolving around puberty.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
A pterygium is a triangular, wing-shaped fold of degenerative bulbar conjunctiva that encroaches onto the cornea, usually on the nasal side and within the interpalpebral (exposed) zone. It is a degenerative (elastotic) change strongly related to chronic exposure to ultraviolet light, dust, wind and a hot, dry climate — hence its frequency in outdoor workers in sunny regions.
PARTS
A pterygium has a head (the apex advancing onto the cornea), a neck, and a body (over the sclera). Two named features are examinable: the cap or Fuchs' patch (a grey, avascular zone just ahead of the head) and Stocker's line (an iron deposition line in the corneal epithelium in front of the advancing head).
Head (apex on cornea) + cap
Body (over sclera)
Cornea
Nasal side → triangular fibrovascular conjunctiva encroaching onto the cornea
Pterygium: a triangular fold of degenerative bulbar conjunctiva advancing from the nasal side onto the cornea, with its head (apex, with the grey Fuchs' cap), neck and body.
CLINICAL FEATURES
Many pterygia are asymptomatic or a cosmetic concern; others cause redness, irritation and a foreign-body sensation. As it advances it can induce astigmatism (by traction on the cornea), obstruct the visual axis if it crosses the pupil, and — when large — restrict ocular movement. It may be progressive or atrophic (quiescent).
PTERYGIUM VS PSEUDOPTERYGIUM
Pterygium
Pseudopterygium
Nature
Degenerative
Post-inflammatory (after ulcer/burn)
Site
Nasal, interpalpebral
Anywhere
Probe test
Cannot pass under neck
Probe passes under the neck
Course
Progressive
Stationary
MANAGEMENT
Mild — reassurance, lubricants, sunglasses (UV protection) and decongestants.
Surgery — indicated for a threatened visual axis, significant astigmatism, cosmesis, restricted movement, or before cataract surgery: excision with a conjunctival autograft (lowest recurrence) or amniotic membrane graft, sometimes with adjunctive mitomycin C. Bare-sclera excision has a high recurrence rate and is avoided.
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CLINICAL PEARL: A pterygium is a triangular, UV-related fibrovascular encroachment of conjunctiva onto the cornea, typically nasal, with a Stocker's line and Fuchs' patch. Distinguish it from a pseudopterygium (post-inflammatory, occurs anywhere, and a probe passes under its neck). Treat surgically with excision plus conjunctival autograft (bare-sclera excision recurs).
PATHOLOGY — ELASTOTIC DEGENERATION
The underlying pathology of a pterygium is elastotic (actinic) degeneration of the subconjunctival collagen, driven by chronic ultraviolet exposure, with fibrovascular proliferation that advances onto the cornea. As the head invades, it destroys Bowman's layer of the cornea, which is why an advanced or recurrent pterygium can leave corneal scarring and astigmatism even after removal. Understanding that this is a UV-driven degenerative process explains both its distribution (the exposed interpalpebral zone, nasal side) and the central role of UV protection in prevention.
WHY IT AFFECTS VISION
A pterygium can affect vision in three ways worth spelling out. First, by traction on the cornea it induces astigmatism (usually with-the-rule flattening along its axis), blurring vision even before it reaches the pupil. Second, if it advances across the visual axis, it directly obscures the pupil. Third, in advanced cases it can restrict ocular movement and cause diplopia. These mechanisms determine the indications for surgery — a threatened visual axis, significant astigmatism, or restricted movement — rather than mere presence of the lesion.
RECURRENCE & THE ROLE OF GRAFTS
The major challenge in pterygium surgery is recurrence, which can be more aggressive than the original lesion. Bare-sclera excision (simply removing the pterygium and leaving the sclera exposed) has a high recurrence rate, so modern surgery adds a conjunctival autograft (moving a piece of the patient's own conjunctiva to cover the defect), which has the lowest recurrence rate, or an amniotic membrane graft. Adjuncts such as mitomycin C further reduce recurrence. This focus on preventing recurrence is the defining principle of pterygium surgery.
A NOTE ON CONSERVATIVE MEASURES & PREVENTION
Because a pterygium is UV-driven, prevention and conservative management centre on reducing environmental exposure: wearing UV-blocking sunglasses and a wide-brimmed hat, and protecting the eyes from dust and wind, both slow progression and reduce recurrence after surgery. For symptomatic but non-progressive lesions, lubricant drops and occasional topical decongestants or a short anti-inflammatory course for inflammation keep the eye comfortable. These simple measures matter because they address the underlying cause, and are advised both before considering surgery and afterwards to protect the graft.
SOURCES: Khurana's Comprehensive Ophthalmology; Parsons' Diseases of the Eye.
THE CONCEPT
A pinguecula is a common, benign, yellowish-white, slightly raised deposit of degenerated conjunctival tissue on the bulbar conjunctiva near the limbus, in the interpalpebral zone (nasal more than temporal). It results from hyaline and elastotic degeneration of the conjunctival stroma, related to ageing and chronic ultraviolet/dust exposure — essentially the same aetiology as a pterygium.
KEY DISTINCTION & FEATURES
The crucial point is that, unlike a pterygium, a pinguecula does NOT encroach onto the cornea — it remains on the conjunctiva at the limbus. It is usually asymptomatic and noticed as a small yellowish nodule, though it may occasionally become inflamed (pingueculitis), causing localised redness and irritation.
MANAGEMENT
Management is generally reassurance, with lubricants and UV protection; a topical anti-inflammatory settles an episode of pingueculitis. Excision is rarely needed — only for cosmesis or recurrent inflammation.
PINGUECULA VS PTERYGIUM
The key exam point is the contrast with a pterygium. Both are UV-related degenerative changes of the interpalpebral conjunctiva, but a pinguecula stays on the conjunctiva at the limbus and never invades the cornea, whereas a pterygium actively encroaches onto the cornea in a triangular, wing-shaped fashion. A pinguecula is therefore essentially a cosmetic/comfort issue, while a pterygium can threaten vision — which is why the two are distinguished. Occasionally a pinguecula may be the precursor from which a pterygium later develops.
THE BOTTOM LINE
A pinguecula is a benign UV-related degenerative conjunctival deposit at the limbus that, unlike a pterygium, never invades the cornea, and needs only reassurance, lubricants and UV protection.
A NOTE ON PINGUECULITIS
Occasionally a pinguecula becomes acutely inflamed (pingueculitis), presenting with localised redness, swelling and irritation over the lesion, often after exposure to sun, wind or dust. This is managed with lubricants and a short course of a topical anti-inflammatory (a mild steroid or NSAID), together with UV and dust protection. It settles without lasting harm, and recognising it prevents an inflamed pinguecula being mistaken for a more serious problem — reinforcing that the pinguecula itself is a benign degenerative change.
A NOTE ON THE SHARED UV AETIOLOGY
It is worth appreciating that pinguecula, pterygium and even conjunctival xerosis share a common thread of chronic environmental (ultraviolet, dust, wind) exposure and ageing degeneration of the conjunctiva. This is why they are commonest in people who work outdoors in sunny, dusty climates, why they favour the exposed interpalpebral zone, and why the same protective advice — UV-blocking sunglasses, hats and avoidance of dust — applies across the group. Placing the pinguecula within this family of degenerative conjunctival changes helps make sense of its appearance, distribution and management.
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KEY POINTS TO REMEMBER
Pinguecula = benign yellowish-white raised deposit of degenerated (hyaline/elastotic) conjunctiva near the limbus (interpalpebral, nasal > temporal); UV/age-related.
Does NOT encroach onto the cornea (key difference from pterygium).
Usually asymptomatic; may become inflamed (pingueculitis).
A subconjunctival haemorrhage is a bright red, flat, sharply-defined patch of blood beneath the conjunctiva, caused by rupture of a small conjunctival or episcleral blood vessel. Despite its alarming appearance, it is almost always painless, harmless, and associated with completely normal vision — an important reassurance for the patient.
CAUSES
It may be spontaneous — often after a sudden rise in venous pressure (a Valsalva manoeuvre from coughing, sneezing, straining or vomiting) — or due to trauma, hypertension, bleeding disorders or anticoagulants, and whooping cough. A recurrent or spontaneous haemorrhage warrants checking blood pressure and clotting.
MANAGEMENT
The haemorrhage resolves spontaneously over one to two weeks, changing colour as it clears. Management is reassurance, with measurement of blood pressure and consideration of a clotting screen if recurrent. If there is a history of significant trauma, one must exclude a more serious globe injury (e.g. an occult rupture) rather than dismiss the red eye.
A NOTE ON WHEN TO WORRY
Although almost always benign, a subconjunctival haemorrhage occasionally needs a second look. Recurrent or bilateral haemorrhages prompt checking for hypertension, a bleeding disorder, or the effect of anticoagulants/antiplatelets. A haemorrhage following significant trauma — especially a boggy, dark haemorrhage with no visible posterior limit, reduced vision, or a soft eye — may conceal an occult scleral rupture (open-globe injury) and must be referred urgently. Knowing these red flags prevents a serious injury being dismissed as a trivial red patch.
THE BOTTOM LINE
A subconjunctival haemorrhage is a dramatic-looking but harmless collection of blood under the conjunctiva that resolves in 1–2 weeks; check blood pressure/clotting if recurrent and exclude a globe injury if traumatic.
A NOTE ON THE APPEARANCE OVER TIME
A helpful teaching point is how a subconjunctival haemorrhage evolves in colour as it clears — much like a bruise elsewhere — starting bright red, then fading through orange and yellow over one to two weeks as the blood is broken down and reabsorbed. Its flat, sharply-demarcated, uniformly red appearance with normal vision and a comfortable eye is characteristic and reassuring. Explaining this natural course to an anxious patient is a key part of management, since the alarming look of the eye is out of all proportion to its trivial significance in the absence of trauma or a bleeding tendency.
A NOTE ON RECURRENT SPONTANEOUS HAEMORRHAGE
When subconjunctival haemorrhages are recurrent or occur without any obvious precipitant, a more thorough search is justified. Beyond blood pressure, this includes reviewing anticoagulant and antiplatelet medication, screening for a bleeding disorder (platelet count, clotting profile), and considering systemic conditions that predispose to bleeding. In older patients the commonest associations remain hypertension and antithrombotic drugs, whereas in a young patient a genuinely recurrent, unexplained pattern warrants a lower threshold for haematological assessment. This targeted work-up ensures the rare significant cause behind an otherwise trivial sign is not overlooked.
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KEY POINTS TO REMEMBER
Subconjunctival haemorrhage = bright red, flat, well-defined patch of blood under the conjunctiva from a ruptured small vessel; painless, vision normal.
Check BP (± clotting) if recurrent/spontaneous; exclude globe injury if traumatic.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Phlyctenular conjunctivitis is a nodular inflammation of the conjunctiva (and often the cornea) caused by a delayed (Type IV) hypersensitivity reaction to microbial antigens — classically tuberculoprotein (in tuberculosis), but also staphylococcal protein. It typically affects malnourished children living in poor, unhygienic conditions, and reflects an allergic response rather than direct infection of the eye.
CLINICAL FEATURES
The characteristic lesion is a small, pinkish-white, raised nodule (the 'phlycten') near the limbus, surrounded by a zone of conjunctival hyperaemia. There is lacrimation, photophobia and irritation. When the cornea is involved (phlyctenular keratitis), the photophobia is intense and there may be corneal scarring or ulceration.
MANAGEMENT
The nodule responds rapidly to topical corticosteroids. Crucially, one must identify and treat the underlying cause — screening for and treating tuberculosis, improving nutrition and hygiene, and treating any staphylococcal blepharitis — because the eye disease is a marker of an underlying systemic or focal problem.
A NOTE ON THE TB LINK
The classical and examinable association of phlyctenular disease is with tuberculosis: the phlycten represents a delayed hypersensitivity response to tuberculoprotein in a sensitised child, so its presence should prompt a search for underlying TB (or other focus of infection) and assessment of nutrition. Historically it was a marker of childhood tuberculosis and malnutrition, and even today, in endemic areas, recurrent phlyctenular conjunctivitis warrants systemic evaluation rather than treatment of the eye alone — the eye sign being a window onto a systemic problem.
THE BOTTOM LINE
Phlyctenular conjunctivitis is a delayed-hypersensitivity nodular inflammation (classically to tuberculoprotein) in malnourished children, treated with topical steroids and by finding and treating the underlying cause.
A NOTE ON RECURRENCE & PREVENTION
Phlyctenular disease has a tendency to recur as long as the underlying stimulus persists, so lasting control depends on more than treating each episode. Measures include treating any focus of infection (tuberculosis, chronic staphylococcal blepharitis, worm infestation), improving nutrition and hygiene, and ensuring general health. In a child with recurrent phlyctens, this systemic and preventive approach is what breaks the cycle, again illustrating that the eye lesion is a hypersensitivity marker of an underlying condition rather than a primary ocular infection to be treated in isolation.
A NOTE ON PHLYCTENULAR KERATITIS
When the hypersensitivity reaction involves the cornea, it produces phlyctenular keratitis, which is more serious than the conjunctival form. A phlycten at the limbus may migrate onto the cornea, dragging a leash of vessels behind it (a fascicular ulcer), and repeated episodes can leave corneal scarring and vascularisation that impair vision. Intense photophobia and blepharospasm are typical. This corneal involvement raises the stakes, reinforcing the need for prompt topical steroids under supervision and diligent treatment of the underlying cause to protect sight.
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KEY POINTS TO REMEMBER
Phlyctenular conjunctivitis = nodular inflammation from delayed (Type IV) hypersensitivity to microbial antigens (classically tuberculoprotein; also Staph).
Malnourished children, poor hygiene; small pinkish-white limbal nodule (phlycten) with surrounding hyperaemia, lacrimation, photophobia.
Corneal involvement (phlyctenular keratitis) → intense photophobia, possible scarring.
Topical steroids (rapid response) + treat the underlying cause (TB, nutrition, hygiene, staph blepharitis).
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Bitot's spots are a clinical sign of Vitamin A deficiency (xerophthalmia). They are triangular, foamy or cheesy, silvery-white raised patches of keratinised conjunctiva, found in the interpalpebral zone (temporal more than nasal), on a background of dry, lustreless conjunctiva (conjunctival xerosis). They result from squamous metaplasia and keratinisation of the conjunctival epithelium when vitamin A is lacking.
THE XEROPHTHALMIA SPECTRUM
Bitot's spots are one point on the spectrum of ocular vitamin A deficiency, which progresses as: night blindness → conjunctival xerosis and Bitot's spots → corneal xerosis → keratomalacia (corneal melting), the last causing irreversible blindness. It is a major cause of childhood blindness in malnourished populations.
MANAGEMENT
Treatment is Vitamin A supplementation (following the WHO high-dose regimen for xerophthalmia), together with a vitamin A-rich diet and treatment of the underlying malnutrition or precipitating illness (e.g. measles, diarrhoea). Early treatment reverses the conjunctival changes and, importantly, prevents progression to blinding corneal disease.
A NOTE ON NIGHT BLINDNESS & THE EARLIEST SIGN
It is worth remembering that the earliest symptom of vitamin A deficiency is night blindness (nyctalopia) — impaired dark adaptation from a lack of rhodopsin in the rod photoreceptors — which precedes the conjunctival and corneal changes. Recognising night blindness (and conjunctival xerosis/Bitot's spots) as early, reversible stages is crucial, because prompt vitamin A treatment at this point prevents progression to keratomalacia, the irreversible corneal melting that causes permanent blindness. This staged progression underlies mass vitamin A prophylaxis programmes for children.
THE BOTTOM LINE
Bitot's spots and conjunctival xerosis are early, reversible signs of vitamin A deficiency on the xerophthalmia spectrum, treated with vitamin A supplementation and nutrition to prevent progression to blinding keratomalacia.
A NOTE ON MASS PROPHYLAXIS PROGRAMMES
Because vitamin A deficiency is a leading, preventable cause of childhood blindness in poor populations, it is tackled at a public-health level. Programmes deliver high-dose vitamin A supplements to young children at regular intervals (often linked to immunisation), promote vitamin A-rich foods and breastfeeding, and treat precipitating illnesses such as measles (which rapidly depletes vitamin A and can trigger keratomalacia). Recognising Bitot's spots in a child should therefore prompt not only treatment of that child but consideration of the wider nutritional context — a strong community-ophthalmology theme.
A NOTE ON KERATOMALACIA — THE BLINDING END-STAGE
The gravest consequence of untreated vitamin A deficiency is keratomalacia — a rapid softening and liquefactive necrosis ('melting') of the cornea — which can destroy the eye within days and is a leading cause of irreversible childhood blindness in malnourished populations, often precipitated by measles or severe diarrhoea. Its danger is precisely why the earlier, reversible signs (night blindness, conjunctival xerosis, Bitot's spots) must be recognised and treated promptly with vitamin A. Bitot's spots are thus an important early warning that catastrophic corneal disease may follow if deficiency is not corrected.
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KEY POINTS TO REMEMBER
Bitot's spots = sign of Vitamin A deficiency (xerophthalmia): triangular, foamy/cheesy, silvery-white keratinised conjunctival patches (interpalpebral, temporal > nasal) on dry conjunctiva.
Due to squamous metaplasia/keratinisation; part of the xerophthalmia spectrum: night blindness → conjunctival xerosis/Bitot's → corneal xerosis → keratomalacia (blindness).
Major cause of childhood blindness in malnutrition.
Treat with Vitamin A supplementation (WHO regimen) + diet + treat underlying malnutrition/illness; early treatment prevents blinding corneal disease.
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SOURCES: Khurana's Comprehensive Ophthalmology; WHO xerophthalmia classification.
THE CONCEPT
Angular conjunctivitis is a chronic conjunctivitis that characteristically affects the angles (canthi) of the eye. It is classically caused by the diplobacillus of Moraxella (Moraxella lacunata / Axenfeld) — and sometimes by staphylococci — organisms that produce a proteolytic enzyme that macerates the skin at the canthi.
CLINICAL FEATURES
The hallmark is redness, maceration and excoriation of the skin at the outer (and inner) canthi, with a foreign-body sensation, irritation and a small amount of mucoid discharge collecting at the angles. The inflammation is localised to the canthal regions rather than the whole conjunctiva.
MANAGEMENT
Treatment is with topical antibiotics effective against Moraxella — oxytetracycline — and, classically, zinc (as zinc sulphate drops), which inhibits the proteolytic enzyme of the diplobacillus. Attention to lid hygiene is also helpful.
A NOTE ON THE ROLE OF ZINC
A point that often earns marks is why zinc is used in angular conjunctivitis. The Moraxella (Axenfeld) diplobacillus produces a proteolytic enzyme that macerates and excoriates the skin at the canthi, and zinc inhibits this enzyme. Therefore zinc sulphate drops, combined with an antibiotic effective against Moraxella (such as oxytetracycline), address both the organism and the mechanism of tissue damage — a neat example of targeting a specific pathogenic mechanism.
THE BOTTOM LINE
Angular conjunctivitis is a chronic inflammation of the canthi caused by the Moraxella diplobacillus, treated with oxytetracycline and zinc sulphate (which inhibits its proteolytic enzyme).
A NOTE ON THE CHRONIC, INDOLENT COURSE
A characteristic worth noting is that angular conjunctivitis tends to run a chronic, low-grade, indolent course rather than an acute one, with persistent maceration and irritation localised to the canthi. Because it is confined to the angles and driven by a specific organism and its enzyme, it responds well to targeted treatment (oxytetracycline plus zinc) but can relapse if treatment is stopped too early or lid hygiene is poor. Recognising its distinctive canthal distribution distinguishes it from the diffuse redness of ordinary infective conjunctivitis.
A NOTE ON THE DIFFERENTIAL
Angular conjunctivitis should be distinguished from other causes of redness and soreness at the canthi, notably angular blepharitis (inflammation of the lid margins at the angles, often staphylococcal) and contact dermatitis of the canthal skin. The characteristic combination of chronic canthal maceration with a Moraxella diplobacillus on scraping, responding to zinc and tetracycline, points to angular conjunctivitis. Recognising this specific, mechanism-based entity — rather than treating it as ordinary conjunctivitis — is what leads to the correct, targeted therapy and lasting resolution.
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KEY POINTS TO REMEMBER
Angular conjunctivitis = chronic conjunctivitis at the angles (canthi); classically caused by the Moraxella (Axenfeld) diplobacillus (also Staph).
Redness, maceration and excoriation of the canthal skin, foreign-body sensation, mucoid discharge at the angles.
The organism produces a proteolytic enzyme that macerates the skin.
Treat with topical oxytetracycline + zinc sulphate (inhibits the proteolytic enzyme) + lid hygiene.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Symblepharon is an adhesion between the palpebral conjunctiva (lining the lid) and the bulbar conjunctiva (covering the globe), or between the lid and the cornea. It forms when there are raw, de-epithelialised surfaces on both the lid and the globe that heal together — so its causes are conditions that damage the conjunctival surface on both sides.
CAUSES & TYPES
It typically follows chemical or thermal burns, Stevens–Johnson syndrome, ocular pemphigoid, trachoma, and trauma. It is classified by extent as anterior (adhesion at the fornix margin), posterior (deep in the fornix), or total (the fornix obliterated).
COMPLICATIONS & MANAGEMENT
Symblepharon causes restricted movement of the eye and lid, diplopia, lagophthalmos (inability to close the lids, with exposure), and cosmetic disfigurement. Management emphasises prevention during the acute healing phase — sweeping the fornices with a glass rod or inserting a symblepharon ring/shell to keep the raw surfaces apart. Established symblepharon requires surgical division with grafting (conjunctival or mucous-membrane graft) to reconstruct the fornix.
A NOTE ON PREVENTION IN CHEMICAL BURNS
Because symblepharon is a devastating and difficult-to-treat complication, prevention during the acute phase is paramount, particularly after chemical burns. Measures include frequent sweeping of the fornices with a sterile glass rod to break early adhesions, insertion of a symblepharon ring or shell to keep the raw surfaces apart, and aggressive treatment of the underlying inflammation. Getting the acute management right dramatically reduces the later burden of adhesion, movement restriction and exposure — a strong argument for prompt, correct emergency care of ocular surface injuries.
THE BOTTOM LINE
Symblepharon is an adhesion between the lid and globe from raw conjunctival surfaces healing together (burns, Stevens–Johnson, trachoma), best prevented during acute healing and otherwise treated by surgical division and grafting.
A NOTE ON THE UNDERLYING CAUSES TO REMEMBER
It is worth committing to memory the principal causes of symblepharon, as they recur in exams: chemical burns (especially alkali), thermal burns, Stevens–Johnson syndrome/toxic epidermal necrolysis, ocular cicatricial pemphigoid, trachoma, and severe membranous conjunctivitis (diphtheria), as well as trauma and surgery. What unites them is the creation of raw, de-epithelialised surfaces on both the palpebral and bulbar conjunctiva simultaneously, which then adhere during healing. Identifying and treating these underlying conditions promptly — and protecting the fornices during the acute phase — is the key to preventing this disabling complication.
A NOTE ON THE PRINCIPLES OF SURGICAL CORRECTION
When symblepharon is established and disabling, surgical correction follows clear principles: the adhesion is divided to free the lid from the globe, and — crucially — the resulting raw surfaces are resurfaced with a graft (conjunctival autograft, amniotic membrane, or a buccal mucous-membrane graft) to stop them re-adhering. A symblepharon ring or conformer is often kept in place afterwards to maintain the reconstructed fornix during healing. Because recurrence is common, careful resurfacing and postoperative separation of the surfaces are the keys to a durable result — mirroring the prevention principle applied to established disease.
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KEY POINTS TO REMEMBER
Symblepharon = adhesion between palpebral and bulbar conjunctiva (or lid and cornea), from raw surfaces on both sides healing together.
Prevent during healing (glass-rod sweeping, symblepharon ring); established cases need surgical division + graft.
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SOURCES: Khurana's Comprehensive Ophthalmology.
THE CONCEPT
Some severe conjunctival inflammations produce a membrane of fibrinous exudate on the conjunctival surface. It is important to distinguish a true membrane from a pseudomembrane, because they differ in how firmly they are attached and in what they signify.
TRUE MEMBRANE VS PSEUDOMEMBRANE
True membrane
Pseudomembrane
Nature
Fibrin infiltrating the epithelium
Coagulated fibrin on the surface
On removal
Bleeds, leaving a raw surface
Peels off easily, no bleeding
Causes
Corynebacterium diphtheriae, severe streptococcal
Adenoviral, gonococcal, vernal, chemical burns, Stevens–Johnson
SIGNIFICANCE & MANAGEMENT
A true membrane (diphtheritic conjunctivitis) is the more serious, being firmly incorporated into the epithelium. Both types can lead to conjunctival scarring and symblepharon as they heal. Management is to treat the underlying cause (e.g. antibiotics and antitoxin for diphtheria), gently remove pseudomembranes, and take measures to prevent symblepharon during healing.
A NOTE ON DIPHTHERITIC CONJUNCTIVITIS
The classic cause of a true membrane is Corynebacterium diphtheriae, producing diphtheritic (membranous) conjunctivitis — now rare because of immunisation but historically important and still examined. The membrane is firmly incorporated into the epithelium, so removal bleeds and leaves a raw surface that heals with scarring and symblepharon. It requires systemic antibiotics and diphtheria antitoxin, plus measures to prevent symblepharon. Its severity contrasts with the benign, easily-peeled pseudomembranes of adenoviral or vernal conjunctivitis.
THE BOTTOM LINE
A conjunctival membrane is either a true membrane (fibrin infiltrating the epithelium, bleeds on removal, e.g. diphtheria — more serious) or a pseudomembrane (surface fibrin, peels easily, e.g. adenoviral/vernal); both are treated by addressing the cause and preventing symblepharon.
A NOTE ON THE SHARED COMPLICATION OF SCARRING
A unifying point about both true and pseudomembranes is that, whatever their cause, the inflamed and often de-epithelialised conjunctival surface can heal with scarring, leading to symblepharon, fornix shortening, dry eye and, in severe cases, lid and corneal complications. This is why, beyond treating the specific cause and gently removing pseudomembranes, active measures to prevent adhesion during healing are important. It also links this topic to symblepharon and to the cicatrising conjunctivitides, showing how a membranous conjunctivitis can have consequences long after the acute infection has resolved.
A NOTE ON REMOVAL & MANAGEMENT
The practical management differs between the two: a pseudomembrane can and should be gently peeled away (it separates easily without bleeding), which relieves symptoms and reduces the inflammatory load, whereas a true membrane is firmly adherent and forcible removal causes bleeding and further damage. Alongside removing pseudomembranes, treatment is directed at the underlying cause (antibiotics and antitoxin for diphtheria, supportive care and hygiene for adenoviral disease, allergy control for vernal), with lubrication and measures to prevent symblepharon throughout. This distinction in handling is a useful practical corollary of the true-versus-pseudo classification.
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KEY POINTS TO REMEMBER
A conjunctival membrane may be a true membrane (fibrin infiltrating the epithelium; bleeds on removal) or a pseudomembrane (surface fibrin; peels off easily, no bleeding).
True membrane: Corynebacterium diphtheriae, severe streptococcal (more serious).
Pseudomembrane: adenoviral, gonococcal, vernal, chemical burns, Stevens–Johnson syndrome.
Both can cause scarring/symblepharon; treat the cause, remove pseudomembranes, prevent symblepharon.