Anisophoria after implantation of an intraocular lens

After extracapsular cataract extraction, a Simcoe-style posterior chamber intraocular lens was implanted in the left eye of a 69-year-old patient. The visual acuity of the right eye was 20/25 with +3.0 diopter correction. Probably as a result of a biometric error, the left eye was rendered myopic (-1.75 -3.00 X 25 degrees). This anisometropia caused a disturbing diplopia, which could be explained by anisophoria rather than by aniseikonia. The problem of anisophoria is discussed, along with suggestions for correcting the problem.