Abstract
Purpose:
This study aimed to determine the independent association of distance of limbal cataract incision from pre-operative axis of astigmatism to post-operative degree of manifest astigmatism in patients with Toric intraocular lens (IOL) implantation.
Methods:
In this retrospective study, 81 eyes with cataract and mild to high corneal astigmatism (range 0.75 to 4.25 diopters) were analyzed. 59 patients were implanted with a SN6AT3 lens to correct astigmatism <1.50 diopters (D). 11 patients were implanted with a SN6AT4, 6 patients with a SN6AT5, 4 with a SN6AT7, and 1 with a SN6AT9. Mean age of patients was 72, with 38 male subjects. All of these patients underwent phacoemulsification with Acrysof Toric IOL implantation (2.75 mm incision). Main outcome measurement was degree of postoperative astigmatism in relationship to the limbal incision distance from the axis of astigmatism.
Results:
Pre-operatively, mean astigmatism was 1.59 D (range 0.75 to 4.25 D). Post-operatively, mean astigmatism decreased to 0.75 D (range 0 to 2.75 D). No significant difference was found in the mean postoperative astigmatism for patients in which limbal incision was made ≤25 degrees from the axis of astigmatism (n=34), and patients in which limbal incision was made >25 degrees from the axis of astigmatism (n=47); [0.80 D vs. 0.71 D, p=0.26]. Patients implanted with SN6AT3 lenses (n=59) showed less post-operative astigmatism than patients implanted with other toric lenses (n=22); [0.66D vs. 1.00D, p<0.05].
Conclusions:
Toric IOLs are effective in reducing manifest astigmatism. The distance of limbal cataract incision from the pre-operative axis of astigmatism does not appear to influence the degree of post-operative manifest astigmatism. There may be no benefit to moving the site of incision to coincide with an axis of astigmatism.