Which condition is most likely for a patient experiencing acute vision loss in one eye, with fundoscopic exam showing whitening of the retina?

Acute vision loss in one eye, particularly associated with whitening of the retina seen on fundoscopic examination, is most consistent with retinal artery occlusion. This condition occurs when a blockage occurs in the central retinal artery or one of its branches, leading to ischemia of the retina and resulting in sudden and often profound vision loss. The whitening observed on the retina represents areas of ischemia and lack of blood supply, which is characteristic of retinal artery occlusion.

In contrast, retinal vein occlusion typically results in a different presentation with retinal hemorrhages, cotton wool spots, and sometimes edema, rather than the distinct whitening seen in artery occlusions. Macular degeneration primarily affects central vision but does not usually present with acute loss of vision nor retina whitening; instead, it is often more insidious over time. Diabetic retinopathy involves changes due to long-standing diabetes, such as microaneurysms and neovascularization, again presenting different findings on fundoscopic examination.

Therefore, the clinical presentation of acute vision loss and the particular fundoscopic findings lead to the conclusion that retinal artery occlusion is the most likely condition in this scenario.