Tomographic analysis of anterior and posterior surgically induced astigmatism after 2.2 mm temporal clear corneal incisions in femtosecond laser-assisted cataract surgery.

PURPOSE: To evaluate surgically induced astigmatism (SIA) of temporal clear corneal incisions (CCIs) on anterior and posterior corneal curvature after femtosecond laser-assisted cataract surgery (FLACS) using Scheimpflug tomographic measurements. SETTING: Department of Ophthalmology, Goethe University, Frankfurt am Main, Germany. DESIGN: Prospective interventional case series. METHODS: This study enrolled patients who underwent FLACS from June 2013 to July 2014. All eyes were measured with a Pentacam HR preoperatively and at 1 month and 3 months postoperatively, had preoperative total corneal refractive power (TCRP) astigmatism (CATCRP) of 0.50 diopters (D) or less, and received a temporal 2.2 mm incision at 0 degrees and 180 degrees. Vector analysis, using the Holladay-Cravy-Koch formula and the Alpins method, determined astigmatic changes in anterior corneal astigmatism (CAant), posterior corneal astigmatism (CApost), and CATCRP. Student t and Wilcoxon tests were performed. A P value less than 0.05 was considered statistically significant. RESULTS: This study comprised 53 eyes of 38 patients. At 3 months postoperatively, the CAant, CApost, and CATCRP were significantly higher compared with the preoperative values (P = .015, P = .007, P = .008, respectively); however, CApost and CATCRP were significantly lower compared with the limit of 0.50 D (P < .001, P = .01, respectively), whereas CAant was not (P = .11). The mean SIA of CAant, CApost, and CATCRP was 0.25 D ± 0.15 (SD), 0.16 ± 0.11 D, and 0.28 ± 0.17 D, respectively. The angle of error was high (-1.98 ± 52.95 degrees, 1.64 ± 51.27 degrees, and -1.72 ± 48.79 degrees, respectively). CONCLUSION: Femtosecond laser temporal CCIs induce minimal astigmatism in CAant, CApost, and CATCRP, but can be evaluated statistically as astigmatically neutral.