Analysis Of Postoperative Refractive Astigmatism After Non-Toric Iol Implantation

To investigate the relationship between postoperative refractive astigmatism (RA), anterior (ACA) and posterior (PCA) corneal astigmatism, and internal astigmatism in patients with non-toric intraocular lenses (IOL).

Ohashi Eye Center, Sapporo, Hokkaido, Japan

The study included 184 eyes in 129 patients implanted with non-toric IOL from May 2021 to January 2022. TORIC IOL CALCULATOR (BARRETT formula) selected non-toric IOLs for all the eyes when the calculation was conducted based on keratometric values. We used Auto TONOREF™ III (NIDEK) to measure RA, CASIA2 (TOMEY) to measure ACA and PCA and Wavefront Analyzer (KR-1W, TOPCON) to measure corneal and internal astigmatism.

Of the 184 eyes, 32 eyes (17.4%) remained with 1.25D or more postoperative RA (Group A), 66 eyes (35.9%) with 0.75~1.0D (Group B) and 86 eyes (46.7%) with 0.5D or less (Group C). Mean postoperative RA of Group A, Group B and Group C were -1.45D±0.32, -0.83D±0.12 and -0.38D±0.17, respectively (p<0.001). Mean ACA of each group were 0.75D±0.39, 0.67D±0.36 and 0.64D±0.39, respectively. 31.3% of eyes in Group A, 13.6% in Group B and 7.0% in Group C were with against-the-rule (ATR) ACA. Of all the eyes, 25 eyes had ATR ACA and 112 eyes had with-the-rule (WTR) ACA, postoperatively. Mean postoperative RA of the 25 eyes were -0.95D±0.56 and the 112 eyes were -0.64D±0.37 (p<0.05). 91.7% of all the eyes were with ATR internal astigmatism.

More than 10% of the eyes implanted with non-toric IOL had 1.25D or more postoperative RA. Postoperative RA of the eyes with ATR ACA were significantly larger than the eyes with WTR ACA as ATR internal astigmatism were added to the ATR ACA.