Arlt's lines are a characteristic feature of which ocular disease?

• A. Trachoma
• B. Phlyctenular keratoconjunctivitis
• C. Gonococcal conjunctivitis
• D. Bacterial conjunctivitis

Answer: (A)

Arlt's lines reflect chronic scarring of the conjunctiva from trachoma. They appear as horizontal bands of white scar tissue on the upper tarsal conjunctiva, formed by repeated Chlamydia trachomatis–driven inflammation. This scarring is a key feature of late-stage trachomatous disease and can contribute to lid malposition and trichiasis. Other ocular inflammations, like phlyctenular keratoconjunctivitis, produce limbal nodules rather than these tarsal scars, and gonococcal or bacterial conjunctivitis are typically acute with purulent discharge and do not show this characteristic tarsal scarring pattern. Hence, Arlt's lines point to trachoma.