Myopic shift from the predicted refraction after sulcus fixation of PMMA posterior chamber intraocular lenses

Abstract

Background: To evaluate the refractive results of sulcus-fixated polymethylmethacrylate (PMMA) posterior chamber intraocular lenses (PC IOLs) after cataract surgery with and without posterior capsule complications.

Methods: The charts of patients who had undergone cataract surgery were reviewed, and eyes that had received sulcus-fixated PMMA PC IOLs were included in the study. Postoperative refraction, predicted postoperative refraction for in-the-bag IOL with the same diopter, intraoperative posterior capsular complications and vitrectomy, axial eye length, incision type (corneal or scleral), and surgery type were recorded and analyzed. The difference between actual postoperative refraction and predicted refraction for the in-the-bag lens was calculated for each patient.

Results: Of 143 patients (84 men and 59 women), 162 eyes with a sulcus-fixated posterior chamber intraocular lens were investigated. Mean age was 63.7 +/- 12.1 years. A mean myopic shift of -1.02 +/- 0.96 D from the predicted in-the-bag refraction was found. There were no significant differences between eyes with or without vitreous loss-vitrectomy (p = 0.8), eyes with scleral or corneal incisions (p = 0.11), and eyes having phacoemulsification or extracapsular cataract extraction (p = 0.93). In terms of axial length, there were no significant differences between long, normal, or short eyes (p = 0.85).

Interpretation: Sulcus fixation of a PMMA IOL originally planned for in-the-bag fixation caused approximately -1.00 D myopic shift in this study. We recommend that when sulcus fixation is necessary PMMA IOL power should be approximately 1.25 to 1.50 D less than the power for in-the-bag fixation. Axial length, incision type, vitreous loss and use of vitrectomy, and type of the surgery do not appear to alter the postoperative refraction significantly in eyes with sulcus fixation.