What is one of the risk factors for developing wet AMD in the fellow eye when one eye is already affected?

Focal hyperpigmentation is indeed identified as a risk factor for the development of wet age-related macular degeneration (AMD) in the fellow eye when one eye is already affected. Patients with focal hyperpigmentation may have a greater likelihood of retinal pigment epithelium changes and therefore a higher risk of neovascularization, which is characteristic of wet AMD. The presence of these pigmentary changes often indicates an increased propensity for the disease process to affect other parts of the retina, thereby raising the risk for the fellow eye.

Other factors included in the question do not carry the same association with the incidence of wet AMD in the fellow eye. High visual acuity typically suggests less severe retinal damage and is not associated with an increased risk for progression to wet AMD. A lack of drusen, which are yellow deposits under the retina, indicates a lower risk rather than a higher one for developing AMD. Low cholesterol levels are not directly linked to the pathophysiology of AMD progression, focusing instead on vascular health but not on the specific retinal changes that precede AMD.