Changes in corneal astigmatism during 20 years after cataract surgery

Purpose: To examine how corneal astigmatism changes with age over 20 years after cataract surgery and to assess whether the changes differ from those in eyes that did not have surgery. Setting: Hayashi Eye Hospital, Fukuoka, Japan. Design: Retrospective case study. Methods: Using an autokeratometer, corneal astigmatism was measured preoperatively, at baseline (the day the surgically induced astigmatism stabilized), and 10 years and 20 years after baseline. The change in corneal astigmatism between baseline and 10 years, 10 years and 20 years, and baseline and 20 years was determined using power vector analysis and compared between the time intervals and between groups. Results: The study assessed 74 eyes that had phacoemulsification with a horizontal scleral incision more than 21 years ago (surgery group) and 68 eyes that did not have surgery (no-surgery group). The mean vertical/horizontal change in corneal astigmatism (J0) between baseline and 20 years was -0.64 diopter (D) in the surgery group and -0.49 D in the no-surgery group. The oblique change (J45) was -0.03 D in the surgery group and 0.07 D in the no-surgery group. Using multivariate comparison, the mean JO and J45 values were not significantly different between baseline and 10 years or between 10 years and 20 years in both groups (P.2350). The JO and J45 values were not significantly different between the 2 groups at any time interval (P.1331). Conclusions: Corneal astigmatism continues to change toward against-the-rule astigmatism over 20 years after cataract surgery. This change was similar in eyes that did not have surgery.