Yellow filter glasses, often sold as "antifog" or "safety" glasses at department stores and other retail outlets, are claimed to improve contrast sensitivity and the yield of visually perceived objects, particularly under poor conditions (e.g., fog, rain and twilight), by enhancing contrast. These claims were tested in 15 healthy subjects (30 eyes) aged 26 to 58 (mean 42.5) years with the Vision Contrast Test System (VCTS 6500), first with and then without yellow filter glasses. Testing was done with commercial antifog glasses and frame-mounted, hand-held filter glasses of CR (Columbia resin) 39 quality with a yellow tint made by an optician. Contrast sensitivity was found to be significantly improved with yellow filter glasses (p less than 0.0001). The use of yellow filter glasses may safely be recommended to patients who report subjective improvement in contrast vision with such glasses.