Effect of small-incision sutureless cataract surgery on the natural course of astigmatism over 10 to 20 years.

PURPOSE: To retrospectively assess astigmatic changes over 10 years and 20 years after small-incision cataract surgery.

SETTING

5 ophthalmic surgical sites in Japan.

DESIGN

Retrospective case series.

METHODS

Data were collected from patients who had undergone phacoemulsification and implantation of an intraocular lens through a 2.2 to 2.4 mm incision. Preoperative corneal and postoperative manifest astigmatism were converted to power vector notations: horizontal/vertical (J 0 ) and oblique (J 45 ) astigmatism components.

RESULTS

422 eyes of 422 patients were followed for 10 years, and data preoperatively and at 1 month and at 1 year, 3 years, 5 years, 8 years, and 10 years postoperatively were analyzed. The mean J 0 decreased significantly ( P < .001, repeated measures analysis of variance) with an against-the-rule (ATR) shift of 0.363 ± 0.433 diopter (D) over 10 years, but the mean J 45 did not change significantly ( P = .150). Double-angle plot analyses also showed similar ATR shifts in all astigmatism groups. In the subgroup analysis conducted in 34 patients who were followed for 20 years, J 0 declined significantly ( P < .001) by 0.649 ± 0.576 D, whereas J 45 did not ( P = .516). The postoperative changes in J 0 and J 45 were not significantly different between eyes with preoperative with-the-rule, ATR, or oblique astigmatism.

CONCLUSIONS

Postoperative astigmatism continued to shift toward ATR during the follow-up period of 20 years after small-incision cataract surgery, which seems to reflect the natural course of corneal astigmatic changes that commonly occur with aging. ATR astigmatic shifts were similar in both pattern and magnitude regardless of the type of preoperative astigmatism.