Anterior capsule coverage and rotational stability of an acrylic toric intraocular lens

Purpose: To investigate factors related to the rotational stability of an acrylic toric intraocular lens (IOL). Setting: Four ophthalmic surgical sites in Japan. Design: Prospective case series. Methods: The study included 120 eyes of 120 patients undergoing phacoemulsification and implantation of a toric IOL (AcrySof IQ, Alcon Laboratories, Inc.). At 1 hour postoperatively, the area of continuous curvilinear capsulorhexis (CCC) was measured, and the state of anterior capsule coverage on the IOL optic (total on or partial on) was recorded. The toric IOL axis orientation was assessed at the end of surgery and at 1 hour, 1 week, 1 month, and 6 months postoperatively. Multiple regression analysis was performed to explore any clinical factors relevant to IOL rotation from the end of surgery to 6 months postoperatively. The explanatory variables included age, anterior chamber depth preoperatively, axial length, type of corneal astigmatism (with-the-rule, against-the-rule, or oblique astigmatism), area of CCC, state of anterior capsule overlap on IOL optic (total coverage vs partial coverage), and surgical sites (surgeons). Results: The multiple regression analysis in 110 eyes of 110 patients indicated that anterior capsule overlap on the IOL optic was the only variable associated with IOL rotation at 6 months postoperatively ( P = .0482). The mean absolute rotation at 6 months was 1.96 ± 1.81 degrees in the total on group and 3.79 ± 3.12 degrees in the partial on group ( P = .0004). Conclusions: Rotational stability of a single-piece, acrylic toric IOL was better in eyes with total anterior capsule coverage than that in those with partial anterior capsule coverage on the IOL optic.