Keratoconus

Features

•    Progressive corneal thinning and conical protrusion

•    Irregular astigmatism → progressive visual distortion

•    Often bilateral but asymmetric

•    Onset typically in adolescence or young adulthood

Associations

•    Atopy (eczema, asthma)

•    Down syndrome

•    Eye rubbing (e.g., in allergic conjunctivitis)

Signs

•    Scissoring reflex on retinoscopy

•    Fleischer ring (iron deposition)

•    Vogt striae (stromal lines)

Management

•    Rigid gas-permeable contact lenses

•    Corneal cross-linking (halts progression)

•    Keratoplasty (severe cases)

Corneal Ulcers (Keratitis)

Causes

•    Bacterial: most common; contact lens wearers (Pseudomonas)

•    Viral: herpes simplex → dendritic ulcers (fluorescein staining)

•    Fungal: trauma with vegetative matter; contact lens wear

Features

•    Severe eye pain

•    Redness, photophobia

•    Corneal opacity or ulcer visible

•    Purulent discharge

Management

•    Urgent ophthalmology referral

•    Intensive topical antibiotics (for bacterial)

•    Antivirals for HSV keratitis (e.g., topical aciclovir)

Dry Eye Disease (Keratoconjunctivitis Sicca)

Features

•    Foreign body sensation

•    Grittiness, burning, transient blurring

•    Worse after prolonged visual tasks (e.g., screen use)

Causes

•    Sjögren’s syndrome (primary or secondary)

•    Age-related lacrimal hypofunction

•    Medications: antihistamines, anticholinergics, antidepressants

•    Environmental: air conditioning, prolonged screen time

Tests

•    Schirmer’s test (tear production)

Management

•    Artificial tears

•    Treat underlying cause (e.g., systemic disease)

•    Punctal plugs (severe cases)

Extra Revision Pearls

•    Contact lens wearer + corneal ulcer clue → Pseudomonas risk

•    Dendritic ulcer clue → HSV keratitis (avoid steroids!)

•    Young person with progressive astigmatism clue → keratoconus

•    Dry eye + systemic autoimmunity clue → Sjögren’s syndrome

•    Iron ring clue (Fleischer) → keratoconus