In Acanthamoeba keratitis, the clinical feature that most strongly distinguishes it from herpes simplex stromal keratitis is:

• A Radial perineuritis (perineural infiltrates along corneal nerves) ✓
• B Dendritic corneal ulcer with terminal bulbs
• C Geographic stromal ulceration
• D Limbal vascularisation (pannus formation)

Explanation

Radial perineuritis — infiltrates tracking along the corneal nerve fibres visible on slit-lamp or confocal microscopy — is highly characteristic of Acanthamoeba keratitis, caused by the parasite's predilection for neural tissue (neurotropism). This feature differentiates it from HSK, fungal, or bacterial keratitis. Confocal microscopy showing double-walled cysts (10–25 µm) confirms diagnosis. Dendrites in HSK have terminal bulbs and stain with rose bengal; Acanthamoeba may show pseudodendrites without terminal bulbs and lacks stromal ghost vessels early in disease.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.