A 29-year-old female diagnosed with AIDS has been suffering from a progressive blurring of vision in her right eye. On fundoscopic examination, a small white opaque lesion is noted on the retina of her right eye. Most appropriate therapy for this patient?

**Core Concept**
The patient's symptoms are indicative of cytomegalovirus (CMV) retinitis, a common opportunistic infection in individuals with acquired immunodeficiency syndrome (AIDS). CMV retinitis is characterized by a progressive retinal necrosis due to CMV replication in the retina.

**Why the Correct Answer is Right**
Ganciclovir is an antiviral medication that is specifically effective against CMV. It works by inhibiting DNA synthesis in CMV-infected cells, thereby preventing viral replication. Ganciclovir is administered intravenously or orally and is the preferred treatment for CMV retinitis in immunocompromised patients.

**Why Each Wrong Option is Incorrect**
**Option A:** Acyclovir is another antiviral medication, but it is primarily used to treat herpes simplex virus (HSV) infections, not CMV. While acyclovir has some activity against CMV, it is not the preferred treatment for CMV retinitis.
**Option B:** Amantadine is an antiviral medication used to treat influenza A virus infections and Parkinson's disease. It has no activity against CMV and is not indicated for the treatment of CMV retinitis.
**Option C:** Flucytosine is an antifungal medication used to treat cryptococcosis, a fungal infection that can occur in immunocompromised patients. It has no activity against CMV and is not indicated for the treatment of CMV retinitis.

**Clinical Pearl / High-Yield Fact**
In patients with AIDS, CMV retinitis is often the first manifestation of the disease. Prompt initiation of antiviral therapy, such as ganciclovir, is essential to prevent vision loss and preserve retinal function.

**✓ Correct Answer: D. Ganciclovir**

✓ Correct Answer: D. Ganciclovir