This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
An HIV patient complains for visual disturbances fundal examination shows bilateral retinal exudates and perivascular hemorrhages. Which of the following viruses are most likely to be responsible for this retinitis : 
Select and explain. 
A. Herpes  simplex  retinitis, B. Human  herpes  virus, C. Cytomegalovirus, D. EBV
C: Cytomegalovirus
Answer: C: Cytomegalovirus 
Explanation: Ophthalmologic manifestations of HIV infection
• The MC abnormal finding on fundus examination are “cotton wool spots”. They represent area of retinal ischemia secondary to microvascular disease. These lesions are not associated with visual loss.
• CMV Retinitis :
– MC cause of vision loss in AIDS patient.
– Usually occurs when CD-4 <50/ μ l.
– Usually present as painless progressive of vision, patient may also complain of floaters and scintillations.
– The characteristic appearance is that of perivascular hemorrhage and exudate.
– It may be complicated by rheumatogenous retinal detachment.
– Treatment - oral valganciclovir, IV ganciclovir - DOC
• Acute retinal necrosis syndrome = Progressive outer retinal necrosis (PORN) :
– Caused by herpes simplex virus, varicella zoster virus.
– Associated with pain, keratopathy iritis.
– Ophthalmologic examination show widespread pale grey lesions.
– DOC is intravenous acyclovir.
• Other secondary infections include :
– P.carnii - Cause lesion of choroid.
– Toxoplasmosis - Cause chorioretinitis.