Topical antifungal agent used in keratomycosis is:
**Core Concept**
Topical antifungal agents are used to treat fungal infections of the eye, particularly keratomycosis, which affects the cornea. The ideal antifungal agent should have good penetration into the cornea, be effective against a wide range of fungal pathogens, and have a favorable safety profile.
**Why the Correct Answer is Right**
The correct answer is natamycin, which is a polyene antifungal agent that has been shown to be effective in treating keratomycosis. Natamycin works by binding to the fungal cell membrane, disrupting its integrity and ultimately leading to cell death. It has a high affinity for fungal cell membranes and is able to penetrate the cornea, making it an effective treatment for keratomycosis.
**Why Each Wrong Option is Incorrect**
**Option A:** Amphotericin B is a polyene antifungal agent, but it is not typically used topically for keratomycosis due to its high toxicity and potential for causing corneal damage.
**Option B:** Fluconazole is an azole antifungal agent that is effective against a range of fungal pathogens, but it is not typically used topically for keratomycosis due to its poor penetration into the cornea.
**Option C:** Voriconazole is an azole antifungal agent that is effective against a range of fungal pathogens, but it is not typically used topically for keratomycosis due to its poor penetration into the cornea and potential for causing phototoxicity.
**Clinical Pearl / High-Yield Fact**
Natamycin is the only antifungal agent approved by the FDA for topical use in the treatment of keratomycosis. It is essential to note that the choice of antifungal agent should be based on the specific fungal pathogen isolated and the severity of the infection.
**Correct Answer:** C. Natamycin