Influence of incision malposition and toric intraocular lens axis misalignment on surgically-induced astigmatism

Session Details

Session Title: Presented Poster Session: Toric Lenses & IOL Power Calculation

Venue: Poster Village: Pod 1

First Author: : N.Shibata JAPAN

Co Author(s): :    A. Takayama   E. Shibuya   H. Sasaki                 

Abstract Details

Purpose:

We simulated the influence on the actual toric intraocular lens (IOL) axis by incision malposition and toric IOL axis misalignment, using a toric IOL calculator.

Setting:

Kanazawa Medical University Hospital, Uchinada, Ishikawa, Japan

Methods:

Optimum toric IOL axis was determined using an astigmatism planner (VERION, Alcon). Magnitudes of against-the-rule corneal astigmatism (ATRCA) included 1.5 diopter (D) and 2.5D, with expected incision location (EIL) at temporal 180 degrees. Toric IOL axis and surgically induced astigmatism (SIA) were set at 0 degree and 0.5D, respectively. The actual toric IOL axis, residual astigmatism (RA) and effectiveness of astigmatic correction were investigated under each condition of incision malposition of 10 and 20 degrees from EIL and toric IOL axis misalignment of 10 degrees in the clockwise direction.

Results:

Under 1.5D ATRCA and incision malposition of 10 and 20 degrees, the effectiveness of astigmatic correction was 83% (RA: 0.17D) and 61% (0.40D), respectively. After toric IOL axis misalignment, astigmatic correction was 50% (0.51D) and 28% (0.74D), with an actual toric IOL axis of 15 and 18 degrees, respectively. Under 2.5D ATRCA and incision malposition of 10 and 20 degrees, the effectiveness of astigmatic correction was 94% (0.11D) and 83% (0.35D), respectively. After toric IOL axis misalignment, astigmatic correction was 61% (0.79D) and 50% (1.03D), with an actual toric IOL axis of 12 and 14 degrees, respectively.

Conclusions:

The effectiveness of astigmatic correction was decreased by toric IOL axis change induced by incision malposition. It was further decreased by toric IOL axis misalignment during surgery and postoperative toric IOL axis change. In cataract surgery with temporal incision, influence of incision malposition with toric intraocular lens axis misalignment on astigmatism correction is more significant in eyes with mild ATRCA.

Financial Disclosure:

None