Which of the following medications can be prescribed topically q.i.d. for filamentary keratitis, dry eye syndromes, and corneal burns?

• A. Zafirlukast
• B. Albuterol
• C. Theophylline
• D. Acetylcysteine

Answer: (D)

Topical mucolytic therapy helps manage ocular surface disorders where mucus filaments form and irritate the cornea. In filamentary keratitis, filaments composed of mucus and epithelial debris adhere to the corneal surface; dissolving these filaments reduces irritation and promotes healing. In dry eye syndromes, excessive mucus can create strands that worsen symptoms, and a mucolytic can make the tear film more stable. In corneal burns, removing discharged and aggregated mucus debris supports re-epithelialization and comfort.

Acetylcysteine works by breaking disulfide bonds in mucin glycoproteins, lowering mucus viscosity and helping to loosen and remove filaments from the ocular surface. When used as an eye drop four times daily, it provides ongoing mucolytic activity to aid symptom relief and healing.

The other medications listed are not topical treatments for eye surface conditions: zafirlukast is a systemic leukotriene receptor antagonist for asthma, albuterol is a bronchodilator inhaler, and theophylline is a systemic bronchodilator.