Secondary Intraocular Lens Implantation in Longstanding Unilateral Aphakia

Purpose To investigate the effect of secondary intraocular lens (IOL) implantation on binocular vision in patients with unilateral aphakia uncorrected consecutively for 3 years or more. Methods This study included nine patients who underwent secondary IOL implantation, but had remained in a unilateral aphakic state, without being corrected, for at least 3 consecutive years at the time of the secondary IOL implant. They also had a postoperative best-corrected visual acuity of better than 20/40 in both eyes. All patients underwent an ophthalmologic examination including best spectacle-corrected visual acuity and binocular alignment. Stereoacuity was evaluated using the Titmus Stereotest and a stereoacuity of 100 sec of arc or better was designated as "good" stereoacuity. Binocularity was determined using the polarized 4-dot test at distance and at near and the reporting of 4 dots were used to establish fusional ability. Results Four of the nine patients (44.4%) showed the highest stereoacuity of 40 sec of arc and another four patients (44.4%) showed a stereoacuity of 50 or 60 sec of arc. Only one patient showed "poor" stereoacuity of 200 sec of arc. All the patients could fuse at near and at distance on the polarized 4-dot test. Diplopia and anomalous eye movements were not found in any patient. Conclusions Secondary IOL implantation can provide good binocular vision even in patients with unilateral aphakia who had not been corrected for 3 years or more.