眼内レンズの偏心による両眼視機能への影響

Effect of decentration of intraocular lens on binocu-lar visual functions

　挿入された眼内レンズが上方に偏心することにより両眼視機能が障害された49歳と66歳の2症例を報告した。両症例とも術前は両眼視機能があったと考えられる。挿入された眼内レンズが偏心することにより映像が黄斑部に投影されず，そのために両眼視機能が障害されたものと考えられた。眼内レンズの術後観察に際し片眼ずつの視力のみならず，両眼視機能にも留意する必要があると思われた。

We observed 2 cases of disturbed binocular visual functions secondary to decentration of implanted posterior chamber intraocular lens (PC-IOL). Both were females, aged 66 and 49 years. PC-IOL was implanted in both eyes 4 years before in the first case. The lens was decentered upwards by 0.8 mm in the right eye and by 1.7 mm in the left. In the second case, IOP was implanted in the right eye 2 years before. The implanted IOP was decentered upwards by 1.9 mm.

Both cases were characterized by normalresponses to synoptophore concerning simultaneous perception, fusion and stereoscopic vision. They responded correctly to titmus fly test and polatest SP. They gave poor scores to titmus circle and animal tests. The discrepancy between tests with synoptophore and other stereotests seemed to arise as the test images were not projected on the fovea due to decentered IOLs. We advocate that due attention be paid to binocular visual functions in the follow-up of patients after IOL implantation surgery.