OP3.1-7 | Conjunctiva and Red Eye — Glossary

A hypodermic needle used tangentially (bevel parallel to the corneal surface, NOT perpendicular) to gently lift an adherent conjunctival or superficial corneal FB; requires slit-lamp or loupe magnification; a perpendicular approach risks full-thickness corneal laceration.

Multi-dose eye drop bottles should be discarded 28 days after first opening, regardless of remaining volume; the preservative cannot guarantee sterility beyond this period and contaminated bottles are a source of ocular infection.

Systemic carbonic anhydrase inhibitor used IV or orally in acute angle-closure glaucoma to rapidly reduce aqueous production and lower IOP; also used in altitude sickness.

Ophthalmic emergency caused by sudden complete closure of the anterior chamber drainage angle, resulting in acute IOP rise (often 50–70 mmHg), severe pain, halos, corneal oedema, and fixed mid-dilated pupil.

Explosive epidemic conjunctivitis caused by Enterovirus 70 or Coxsackievirus A24; characterised by sudden onset with subconjunctival haemorrhages; self-limiting in 5–10 days; no specific treatment.

Corneal epithelial toxicity from repeated topical local anaesthetic use; impairs epithelial healing, reduces protective corneal sensation, and can progress to corneal ulceration; hence topical LAs are clinic-only drugs.

Inflammation of the uveal tract confined to the anterior segment (iris and/or ciliary body); presents with unilateral red eye, deep aching pain, photophobia, keratic precipitates on the corneal endothelium, and miosis or posterior synechiae.

Pathognomonic horizontal white fibrous scar on the upper tarsal conjunctiva, running parallel to and just below the lid margin; the hallmark of TS (Trachomatous Scarring) in trachoma.

Severe bilateral allergic keratoconjunctivitis in adults (20–50 years) with atopic dermatitis; lower lid folds (Dennie-Morgan lines) characteristic; can cause anterior subcapsular cataract, keratoconus, and corneal scarring; does not remit at puberty.

An excision technique for pterygium in which the growth is removed and the sclera is left uncovered; has an unacceptably high recurrence rate of 50–80% and is largely abandoned in favour of conjunctival autograft.

The most common preservative in multi-dose ophthalmic eye drop bottles; prevents microbial contamination; mildly toxic to the corneal epithelium and goblet cells with prolonged or frequent use; patients using >4 drops/day or multiple preserved drops should use preservative-free formulations.

Surgical procedure for cicatricial trichiasis in trachoma: the upper eyelid is split at the grey line and the scarred tarsal plate is rotated outward, turning the lashes away from the cornea; can be performed under local anaesthesia at the district level.

A selective alpha-2 adrenoceptor agonist topical eye drop for open-angle glaucoma; reduces aqueous production and increases uveoscleral outflow; contraindicated in infants (systemic CNS depression risk); absorbed via nasolacrimal route — NLO reduces systemic exposure.

Third-generation cephalosporin; first-line systemic treatment for gonococcal conjunctivitis and neonatal gonococcal ophthalmia; given IM (adults) or IV (neonates); topical alone is insufficient.

Copper toxicity to intraocular tissues from an intraocular copper or brass foreign body; produces Kayser-Fleischer-like ring in the cornea, sunflower cataract in the lens, and progressive retinal damage; requires urgent surgical removal.

Oedema of the bulbar conjunctiva causing a gelatinous translucent swelling of the conjunctival surface; prominent in gonococcal conjunctivitis and severe viral disease.

Broad-spectrum topical antibiotic (0.5% drops, 1% ointment) used as first-line treatment for non-gonococcal bacterial conjunctivitis; not used in contact-lens wearers due to risk of aplastic anaemia.

Perilimbal (circumcorneal) violet-red injection of fine deep episcleral vessels, indicating corneal or uveal inflammation; does not blanch on pressure — distinguishes anterior-segment inflammation from conjunctivitis.

WHO trachoma grade: easily visible corneal opacity over the pupil, dense enough to obscure part of the pupil margin; represents irreversible visual loss from trachoma scarring.

Organized lymphoid aggregates within the conjunctival stroma, concentrated in the fornices; responsible for mucosal immune defence and for generating follicular reactions in viral/chlamydial disease.

Surgical technique for pterygium excision in which the bare scleral defect is covered with a free graft of the patient's own superior bulbar conjunctiva; reduces recurrence rate to <10% compared to 50–80% for bare sclera technique; the current standard of care.

Redness from engorgement of the large, superficial conjunctival vessels, most prominent in the fornices and peripheral bulbar conjunctiva; blanches on pressure; typical of conjunctivitis.

The maximum volume of fluid the conjunctival sac can hold: approximately 7–10 microlitres; a standard eye drop (30–50 μL) overfills this volume — hence only one drop per dose is needed and overflow is expected.

A topical calcineurin inhibitor (T-cell immunosuppressant) used in moderate-to-severe VKC; inhibits T-cell activation and IL-2 production (targeting Type IV component); allows steroid reduction; available as 0.05% or 1% eye drops.

Clinical features that indicate a potentially sight-threatening cause: pain (not gritty), photophobia, pupil abnormality, reduced vision, corneal opacity or ciliary flush — any one warrants urgent ophthalmology referral.

Abnormal accumulation of elastin-like material in the subepithelial conjunctival stroma, caused by UV-B induced degeneration of normal collagen; the histological basis of pinguecula formation.

A granulocyte recruited by Th2 cytokines (IL-4, IL-5, IL-13) in allergic inflammation; the hallmark cell of VKC on conjunctival scraping cytology; releases MBP, eosinophil cationic protein (ECP), and other toxic granule proteins causing corneal epithelial damage.

A toxic granule protein released by degranulating eosinophils in VKC; directly damages the corneal epithelium and is the principal mediator of shield ulcer formation and superficial keratopathy.

Severe adenoviral conjunctivitis (types 8, 19, 37) characterised by follicular conjunctivitis followed by subepithelial corneal infiltrates from day 7–14; highly contagious; requires 2-week workplace exclusion.

Superficial inflammation of the episclera overlying the sclera; bright red, sectoral, usually self-limiting, mild pain; blanches with phenylephrine (distinguishing it from scleritis).

A semi-solid ophthalmic preparation (petrolatum or lanolin base) with prolonged conjunctival sac residence time (~1–2 hours); always instilled LAST in a multi-medication session because it blurs vision and delays absorption of subsequently instilled drops.

The minimum waiting time between instilling two different eye drops in the same session to prevent the second drop from washing out the first; based on the time needed for the conjunctival sac to drain to baseline volume and for the first drug to be absorbed.

Subepithelial dome-shaped avascular lymphoid aggregates on the palpebral conjunctiva, with blood vessels around the periphery but no central vascular core; indicates viral or chlamydial aetiology.

Papillae >1 mm diameter on the upper palpebral conjunctiva, producing a cobblestone or cauliflower surface; pathognomonic of VKC (palpebral form) or GPC; each contains a central vascular core surrounded by eosinophilic infiltration.

Mechanically induced giant papillae on the upper palpebral conjunctiva from contact-lens edge friction, exposed suture, or ocular prosthesis; resolves on removing the offending contact lens; not immunologically driven by allergen.

Mucus-secreting unicellular glands within the conjunctival epithelium; their mucus is essential for the mucin layer of the tear film; reduced in cicatricial conjunctivitis (trachoma, pemphigoid), contributing to dry eye.

Pathognomonic limbal depressions at the site of resolved limbal follicles in trachoma; visible as small indentations at the upper limbus; present even decades after active infection.

Systemic suppression of the hypothalamic-pituitary-adrenal axis by topically instilled corticosteroids absorbed via the nasolacrimal duct; most significant in neonates and infants receiving high-potency topical steroids (e.g. dexamethasone 0.1%) for prolonged periods.

Profuse purulent conjunctivitis that reforms immediately after wiping; caused by Neisseria gonorrhoeae; sight-threatening due to risk of corneal perforation within 24–48 hours; requires systemic ceftriaxone.

Chlamydial conjunctivitis (C. trachomatis serotypes D-K) in adults via genito-ocular transmission or in neonates from birth canal; subacute follicular conjunctivitis with mucopurulent discharge; treated with systemic azithromycin or doxycycline.

The pressure within the eye, normal range 10–21 mmHg as measured by Goldmann applanation tonometry; elevated in acute angle-closure glaucoma and chronic open-angle glaucoma.

Distortion of the corneal curvature in the horizontal meridian caused by a pterygium's fibrovascular tissue pulling on the corneal surface; does not correct with a sphero-cylindrical spectacle lens and does NOT improve with pinhole; resolves with surgical excision.

Progressive non-inflammatory thinning and ectasia of the central cornea producing a cone-shaped forward bulge and irregular astigmatism; associated with VKC and chronic eye rubbing; managed with rigid contact lenses, corneal cross-linking, or (severe) keratoplasty.

A prostaglandin analogue eye drop (0.005%) for open-angle glaucoma; instilled once nightly (timing is important for peak IOP-lowering effect); stored in the refrigerator before opening (2–8°C); may cause iris pigmentation and periorbital skin darkening with long-term use.

The procedure to expose the palpebral conjunctiva of the upper eyelid: patient looks down; cotton bud placed at upper tarsal border; lid lashes grasped gently; lid folded upward and forward over the bud to reveal the palpebral surface.

A developmental choristoma (normal tissue in an abnormal location) at the corneal limbus; white, smooth, present from birth, non-progressive; contains hair follicles or sebaceous glands histologically; lacks the vascularity of pterygium.

Progenitor cells in the palisades of Vogt at the corneoscleral limbus that maintain the corneal epithelial surface and form a barrier preventing conjunctival epithelium from migrating onto the cornea; their dysfunction by UV-B damage is the principal mechanism of pterygium formation.

The recess of the conjunctival sac created by pulling down the lower eyelid; the target for eye drop instillation because it is insensitive (does not trigger blink reflex) and retains the drop before drainage.

Community-level antibiotic distribution (azithromycin) to an entire endemic population regardless of individual infection status; the A component of the SAFE strategy for trachoma control.

A class of topical ocular drugs (sodium cromoglicate, lodoxamide) that inhibit mast-cell degranulation, preventing histamine and mediator release; must be used prophylactically before allergen exposure; no acute relief effect.

Enzymes that degrade extracellular matrix; MMP-2 and MMP-9 are upregulated in pterygium fibroblasts and responsible for dissolution of Bowman's layer as the pterygium head advances onto the corneal surface.

Infection of the corneal stroma by bacteria, fungi, viruses (HSV), or Acanthamoeba; presents with corneal ulceration, hypopyon, and ciliary flush; sight-threatening if not treated urgently.

An intraoperative antimetabolite (alkylating agent) applied topically to inhibit fibroblast proliferation and reduce pterygium recurrence; used as an adjuvant to conjunctival autograft; main complication is scleral thinning/melting with excess dose.

The bush fly, the principal vector for mechanical transmission of Chlamydia trachomatis in trachoma-endemic communities; attracted to ocular and nasal discharge of infected children.

The technique of pressing the index finger against the medial canthus (inner corner) of the eye for 1–2 minutes after instilling eye drops; occludes the lacrimal punctum, preventing drug drainage into the nasolacrimal duct and reducing systemic absorption.

A topical dual-action ophthalmic drug: H1-receptor antihistamine (provides acute itch relief) and mast-cell stabiliser (prevents degranulation); used 1–2× daily for allergic conjunctivitis.

Conjunctivitis in the first 28 days of life; key causes by timing: chemical (day 1), Neisseria gonorrhoeae (day 1–3), Chlamydia trachomatis (day 5–14); requires systemic treatment and microbiological investigation.

A topical local anaesthetic (0.4% drops) used before ocular FB removal to reduce pain and blepharospasm; duration approximately 15 minutes; must not be given as a take-home prescription due to risk of anaesthetic keratopathy with repeated self-use.

Superficial corneal vascularisation extending from the limbus over the upper cornea, occurring in trachoma from repeated corneal irritation by trichiasis; contributes to corneal opacity.

Inflammatory response on the palpebral conjunctiva producing flat-topped elevations each with a central vascular core; seen in bacterial and allergic conjunctivitis; giant papillae (>1 mm) are pathognomonic of vernal keratoconjunctivitis.

A full-thickness laceration of the eye wall (cornea or sclera) by a sharp or high-velocity object; signs: peaked/irregular pupil, uveal prolapse, shallow anterior chamber, subconjunctival haemorrhage to posterior limit, positive Seidel test; never attempt FB removal — refer as an ocular emergency.

Adenoviral conjunctivitis (types 3, 4, 7) with pharyngitis, fever, and bilateral follicular conjunctivitis; milder than EKC with minimal corneal involvement; self-limiting in 2–3 weeks.

Immunological conjunctivitis (delayed hypersensitivity to Mycobacterium tuberculosis or Staphylococcal antigen) presenting as a small nodule (phlycten) at the limbus that migrates across the cornea leaving a leash of vessels.

Pain or discomfort on exposure to light, arising from iris sphincter spasm (uveitis) or corneal nerve irritation (keratitis); its presence in a red eye indicates a potentially serious cause.

A muscarinic agonist (miotic) used topically to constrict the pupil; first-line topical agent in acute angle-closure to re-open the drainage angle; can worsen some forms of open-angle glaucoma.

Yellowish-white degenerative deposit of conjunctival stroma in the interpalpebral zone adjacent to the limbus; does NOT cross the limbus onto the cornea; represents actinic elastosis; not surgical unless inflamed.

A hand-held disc with a small central aperture that eliminates peripheral rays; improves visual acuity if the blur is refractive but does NOT improve VA in organic causes such as corneal oedema or macular disease.

Adhesions between the posterior iris and the anterior lens capsule, formed during anterior uveitis; cause an irregular pupil and, if circumferential (ring synechiae/seclusio pupillae), lead to raised IOP and iris bombé.

Lymph node just anterior to the tragus of the ear; drains the conjunctiva; palpable and tender in viral conjunctivitis (especially adenoviral); absent in uncomplicated bacterial conjunctivitis.

A topical corticosteroid eye drop suspension for intraocular inflammation (uveitis, post-operative); must be shaken before use as the active drug settles; carries risk of steroid-induced IOP elevation and posterior subcapsular cataract with prolonged use.

Ophthalmic drops formulated without benzalkonium chloride, supplied as single-use unit-dose vials or multi-dose BAC-free bottles; preferred for patients using drops >4 times daily or with pre-existing ocular surface disease.

A bedside test to distinguish true pterygium (probe cannot pass under the growth at the limbus — adherent throughout) from pseudopterygium (probe can pass under at the limbus — secondary adhesion only).

False pterygium — a secondary adhesion between the bulbar conjunctiva and the corneal surface after chemical burn, trauma, or severe ulceration; distinguished from true pterygium by the probe test (probe passes under the pseudopterygium at the limbus).

Wing-shaped fibrovascular growth of bulbar conjunctival tissue that crosses the limbus onto the cornea; almost invariably nasal; caused by UV-B damage and limbal stem cell failure; can induce irregular astigmatism and cover the visual axis.

A handheld rotating instrument used under slit-lamp magnification to remove corneal rust rings by gentle debridement of the rust-infiltrated epithelium 24 hours after metallic FB removal.

Brown ring of iron oxide deposits in the corneal epithelium after a metallic FB has been in contact with the cornea for several hours; toxic to the corneal epithelium; should be removed at 24-hour review (not acutely) using a rotating burr or cotton-bud debridement.

WHO comprehensive framework for trachoma elimination: Surgery (bilamellar tarsal rotation for trichiasis), Antibiotics (azithromycin mass drug administration), Facial cleanliness, Environmental improvement.

Deep inflammation of the sclera, presenting with severe boring nocturnal pain, deep red-purple hue, and tenderness; often associated with systemic connective-tissue disease; can threaten scleral integrity.

Most common allergic conjunctivitis; seasonal bilateral red, itchy eyes from pollen; IgE-mediated Type I hypersensitivity; associated with allergic rhinitis; not sight-threatening; responds to antihistamines and allergen avoidance.

A test for aqueous leak from a penetrating corneal wound: fluorescein is applied and a stream of diluted (lighter green) fluorescein flowing from the wound site under cobalt-blue light indicates aqueous outflow — a positive Seidel test confirms a full-thickness wound.

Superficial oval grey epithelial ulcer in the upper-central cornea in VKC; caused by eosinophil major basic protein (MBP) deposited by giant papillae rubbing the cornea; NOT infectious — primary treatment is topical steroids, NOT antibiotics alone.

Iron toxicity from an intraocular iron foreign body; produces rust-coloured iris heterochromia, progressive retinal pigment epithelial damage, and visual loss if the FB is not surgically removed.

A mast-cell stabiliser used topically as 2% eye drops 4× daily for prophylaxis of allergic conjunctivitis; inhibits mast-cell degranulation; onset takes 2–4 weeks; no acute antihistamine activity.

IOP elevation from topical corticosteroid use, occurring in approximately 30% of 'steroid responders' via reduced aqueous outflow through the trabecular meshwork; mandates IOP monitoring in all patients on topical steroids.

Brown horizontal line of haemosiderin (iron) deposits in the corneal epithelium at the leading edge of a pterygium head; pathognomonic of pterygium; best seen under slit-lamp with yellow filter.

Rupture of a small conjunctival vessel producing a flat, bright-red patch on the white sclera; completely painless, no vision change, no discharge; benign and self-resolving in 1–2 weeks.

Grey-white corneal opacities beneath the epithelium appearing in the second week of EKC; represent immune complex deposition; cause photophobia and visual blur; may persist for months.

A foreign body lodged in the subtarsal sulcus under the upper eyelid on the palpebral conjunctival surface; causes vertical linear corneal scratches with each blink; requires upper lid eversion to identify and remove.

A horizontal groove at the inferior margin of the upper tarsal plate on the palpebral conjunctival surface; the most common location for lodging of a foreign body under the upper eyelid.

An eye drop formulation in which the active drug is dispersed as particles in an aqueous vehicle rather than dissolved; settles on standing; must be shaken before use to achieve a uniform concentration; label instruction: 'SHAKE BEFORE USE'.

A patient education method in which the patient is asked to demonstrate or explain back the instructions they have just received; most effective technique for confirming understanding and improving medication compliance.

WHO trachoma grade: ≥5 follicles, each ≥0.5 mm diameter, in the central zone of the upper tarsal conjunctiva; indicates active chlamydial infection in children.

WHO trachoma grade: intense inflammatory thickening of the upper tarsal conjunctiva obscuring more than 50% of the deep tarsal blood vessels; represents heavy chlamydial infection and high infectivity.

A non-selective topical beta-blocker (0.25% or 0.5%) used for open-angle glaucoma to reduce aqueous production; absorbed systemically via nasolacrimal drainage, bypassing hepatic first-pass; contraindicated in asthma and COPD due to risk of bronchospasm.

Chronic cicatricial conjunctivitis caused by Chlamydia trachomatis serotypes A, B, Ba, C; the world's leading infectious cause of preventable blindness; transmitted by flies, discharge, and fomites.

Pathognomonic white chalky deposits at the upper corneal limbus in the limbal form of VKC; histologically represent collections of degenerated eosinophils and epithelial cells; disappear with treatment.

Misdirection of eyelashes toward the eyeball, causing repeated corneal abrasion; in trachoma, arises from cicatricial entropion of the upper eyelid after tarsal scarring.

WHO trachoma grade: white fibrous lines, bands, or sheets on the upper tarsal conjunctiva; the classic form is Arlt's line — a horizontal scar below the lid margin.

WHO trachoma grade: ≥1 eyelash touching the eyeball, or evidence of recent epilation; causes repeated corneal micro-abrasion; requires surgical correction (bilamellar tarsal rotation).

Seasonal bilateral allergic keratoconjunctivitis predominantly affecting young males in hot climates; driven by mixed Type I (IgE-mediated) and Type IV (T-cell/eosinophil) hypersensitivity; characterised by giant papillae, Trantas dots, and potentially sight-threatening corneal complications.

Multiple fine vertical parallel epithelial abrasions on the superior cornea visible with fluorescein staining under cobalt-blue light; the pathognomonic indirect sign of a subtarsal foreign body rubbing the cornea with each blink.