Diffractive bifocal contact lenses in aphakia and pseudophakia. A pilot study.

Diffractive bifocal contact lenses function by diverting incident light to two focal points. Light from near objects is focused by diffraction while that from distant objects is focused by conventional refraction. Both processes occur simultaneously throughout the full aperture of the lens. Fourteen aphakic and pseudophakic contact lens wearers were fitted with diffractive bifocal lenses and observed for an eight week period. Six (42.8%) were satisfied with the visual result. Five subjects (35.7%) discontinued lens wear complaining of poor quality of near vision. We conclude that these lenses may help selected aphakic patients to discard their reading glasses but the low acceptance rate suggests that this type of optic is probably not suitable for implantation as an intraocular lens.