Factors affecting rotation of a posterior chamber collagen copolymer toric phakic intraocular lens

Abstract

Purpose: To evaluate the correlation between postoperative rotation of the toric Implantable Collamer Lens phakic intraocular lens (pIOL) and associated factors.

Setting: Nagoya Eye Clinic, Nagoya, Japan.

Design: Case series.

Methods: The toric pIOL axis was analyzed by calculating the ocular internal cylinder power and axis from the total refractive cylinder and corneal astigmatism using vector analysis (Jaffe and Clayman method). The correlation between the toric pIOL rotation over 6 months postoperatively and the associated factors (ie, age, preoperative manifest refractive sphere, preoperative manifest spherical equivalent, mean keratometric power, axial length, toric pIOL intraoperative fixation angle, postoperative toric pIOL vault [distance between toric pIOL and anterior surface of crystalline lens], toric pIOL spherical power) were evaluated.

Results: The mean age of the 34 patients (58 eyes) was 35.7 years ± 6.5 (SD). The mean rotation 6 months postoperatively was 4.82 ± 6.98 degrees (range 0.0 to 47.2 degrees). The intraoperative toric pIOL fixation angle and postoperative toric pIOL rotation were significantly correlated (Spearman rank correlation: P=.0096 and R(2) = 0.1140; multiple logistic regression analysis: P=.009). In the 1 eye with significant rotation (47.2 degrees), the toric pIOL was exchanged for a larger toric pIOL.

Conclusions: A small toric pIOL rotation occurred during the 6-month follow-up. One cause of rotation could be the intraoperative fixation angle of the toric pIOL. A toric pIOL with a minimum intraoperative fixation angle should be used to prevent postoperative rotation.