Which of the following is NOT a major topical use for fluoroquinolones in ophthalmology?

• A. Bacterial conjunctivitis
• B. Ocular toxoplasmosis
• C. Corneal ulcers related to contact lenses
• D. Corneal abrasions

Answer: (B)

Fluoroquinolones are broad‑spectrum antibiotics used topically in the eye because they inhibit bacterial DNA gyrase and topoisomerase IV, stopping bacterial replication. They’re especially handy for ocular surface infections due to their strong coverage against common pathogens and good penetration into the ocular tissues.

A primary use is for bacterial conjunctivitis, where topical fluoroquinolones can quickly reduce bacterial load on the surface of the eye. They’re also a key option for bacterial keratitis (corneal ulcers), including those related to contact lens wear, since these infections can involve Gram‑negative organisms like Pseudomonas and require robust coverage. For corneal abrasions, topical antibiotics help prevent secondary bacterial infection while the epithelium heals, making fluoroquinolones a common choice there as well.

Ocular toxoplasmosis, on the other hand, is caused by a parasite, Toxoplasma gondii, and is not treated with fluoroquinolones. The standard management involves antiparasitic medications (often with systemic therapy) rather than topical antibiotics. So toxoplasmosis is not a major topical use for fluoroquinolones in ophthalmology.