Abstract
Purpose:
Current cross-sectional data demonstrates that younger patients have with the rule (WTR) astigmatism while older patients have against the rule (ATR) astigmatism. The purpose of this study was to determine if there is any clinically significant change in astigmatism in the post-cataract surgery population over time.
Methods:
A total of 933 patients underwent cataract surgery by a single Ophthalmologist between September 2004 and February 2012. Keratometry measurements including K1, K2, astigmatism power and axis were recorded at a pre-operative visit, 1-month post-operative visit, and at various post-operative time intervals. Patients were classified as WTR, ATR or oblique (OBL) astigmatism. A total of 586 OS and 580 OD were included for analysis. Keratometry measurements were compared using a repeated measures Student’s t-test between data collected at the 1 month post-operative visit and last visit before YAG capsulotomy. Further subgroup analysis was performed on patients with clinically significant astigmatism defined as astigmatism power ≥ 0.75 diopters (D). Patients were further stratified based on their age at surgery or elapsed time between the 1-month post-operative visit and pre-YAG capsulotomy visit.
Results:
The average age of patients with WTR, OBL and ATR astigmatism was 61.60 years, 71.97 years and 76.92 years, respectively. No statistically significant change in astigmatism power or average keratometry was observed between 1-month post-operative visit and pre-YAG capsulotomy visit in all patients or in patients with clinically significant astigmatism. Subsequent stratification and analysis by age and/or elapsed time between 1-month post-operative visit and pre-YAG capsulotomy (up to 5 years) did not show any statistical difference in astigmatism power or axis. Stratification by astigmatism classification at 1-month post-operative visit and elapsed time to pre-YAG capsulotomy did not show any significant difference in astigmatism power or axis.
Conclusions:
Our retrospective study confirms that younger patients have WTR astigmatism and older patients have ATR astigmatism. However, we were unable to detect a statistical change in the astigmatism power or axis in this same patient population despite various subgroup analyses. This data suggests that astigmatism power and axis in the post-cataract surgery population remains stable for at least 5 years following cataract surgery.
Keywords: 428 astigmatism •
445 cataract •
479 cornea: clinical science