Patient response to concentric bifocal contact lenses

We evaluated the visual results and success rate with a center-near concentric simultaneous vision bifocal contact lens. Forty subjects (screened from 175 presbyopic applicants) entered the study and were fitted with the CIBA Spectrum bifocal lenses (BCL) and also with single vision distance contact lenses combined with reading glasses (DCL). Visual acuity and stereoacuity measurements were made at dispensing and after 8 weeks of regular bifocal contact lens wear. At both times, visual acuity measurements with BCL were significantly reduced by 1-1.5 lines compared to DCL. Stereoacuity was reduced by 32-36" with BCL compared to DCL. Thirty-two patients completed the study and 27 chose to continue wearing BCL after completion of the study. None of the subjects had adverse corneal findings or problems of discomfort. The primary reason for BCL discontinuation was blurred vision. The data was retrospectively analyzed to identify risk factors for discontinuance--none were significant.