Posters

A new method to quantify rotational stability of toric intraocular lenses

Poster Details

First Author: P.Gillard BELGIUM

Co Author(s):    P. Betz   M. Hua           

Abstract Details

Purpose:

To improve the evaluation of rotational stability of toric intraocular lenses (IOL) by using opposite landmarks created on the anterior capsulorhexis' edge and to assess the rotational stability of the AT TORBI 709M (Carl Zeiss Meditec) IOL using this new method.

Setting:

Centre Hospitalier Regional de la Citadelle, Liege, Belgium.

Methods:

Twenty-three eyes of 16 consecutive patients with senile cataract and preoperative regular corneal astigmatism greater than 1.75 diopter were included prospectively. An anterior capsulorhexis was fashioned in order to get two sharp landmarks in opposite sites of the capsulorhexis' edge. An IOL (AT TORBI 709 M) was implanted after phacoemulsification. To identify IOL axis and anterior capsular landmarks, retroillumination photographs were taken at the end of the surgery (supine position), 1 day, 1 week, 1 month and 6 months after surgery. The relative position of the IOL to the anterior capsule was determined by calculating the alpha angle between the IOL orientation marks and a line passing through the two landmarks of anterior capsulorhexis' edge. To determine IOL rotation, we compared immediate post-operative alpha angle with alpha angle at 1day, 1 week, 1month and 6 months.

Results:

Measuring the alpha angle was easy because IOL and capsular bag landmarks were obvious on retroillumination photographs. 6 months' photographs were less suitable for analysis because of anterior capsular fibrosis resulting in capsular landmarks alterations. The average IOL rotation was 2.08 ±1.25 degrees at 1 day, 1.75 ±1.26 degrees at 1 week, 2.60 ±1.39 degrees at 1 month and 2.52 ±1.61 at 6 months.

Conclusions:

This new method for measuring postoperative toric IOL axis rotation is probably the most straightforward. The landmarks of anterior capsulorhexis' edge are in the same plane as the IOL orientation marks. The procedure is independent of head tilt or eye rotation. The AT TORBI 709M IOL shows an excellent post-operative rotational stability. FINANCIAL INTEREST: NONE