A method of treating or preventing age-related retinal dysfunction involves administering to a patient a pharmaceutically effective amount of a synthetic retinal derivative repeatedly over a duration of at least about 3 months. Effective synthetic retinal derivatives include 9-cis-retinyl esters, 11-cis-retinyl esters, derivatives and congeners thereof, and combinations thereof. Suitable ester substituents include carboxylates of C1-C10 monocarboxylic acids and C2-C22 polycarboxylic acids.
