Comparison of corneal surgically induced astigmatism calculations based on keratometry measurements made by 2 biometric devices.

PURPOSE: To compare calculated corneal surgically induced astigmatism (SIA) by means of anterior-based keratometry (K) and total keratometry (TK) measurements made by 2 biometric devices.

SETTING

Ophthalmology Department, Shaare Zedek Medical Center, Jerusalem, Israel.

DESIGN

Retrospective, consecutive case series.

METHODS

The medical records of patients who had undergone cataract surgery through a 2.4 mm temporal clear corneal incision by a single surgeon between March 2018 and November 2020 were retrospectively reviewed. Patients for whom there were preoperative and postoperative K measurements assessed by 2 biometric devices, optical low-coherence reflectometry (OLCR) (Lenstar LS900, Haag-Streit, software v. eye suite i/9.1.0.0) and swept-source optical coherence tomography (SS-OCT) (IOLMaster700, Carl Zeiss Meditec AG, software v. 1.80.6.60340), were identified. Corneal SIA (mean vector value) was calculated by vector analysis for 3 groups: SS-OCT(K), SS-OCT(TK), and OLCR(K). Bivariate analyses were applied for comparisons.

RESULTS

147 eyes of 123 patients (73 right eyes and 74 left eyes) were enrolled in the study. The right eye corneal SIA values were 0.09 diopters (D) @ 136 degrees, 0.09 D @ 141 degrees, and 0.07 D @ 123 degrees for the SS-OCT(K), SS-OCT(TK), and OLCR, respectively. The corresponding left eye corneal SIA values were 0.13 D @ 120 degrees, 0.11 D @ 123 degrees, and 0.08 D @ 120 degrees. There were no statistically significant differences between the mean vector value and variance of the corneal SIA for the right (P = .78 and P = .65) and the left (P = .75 and P = .37) eyes of the 3 groups.

CONCLUSIONS

Corneal SIA values were low (0.07 to 0.13 D) and similar for the SS-OCT and the OLCR biometric devices with standard K measurements. TK measurements yielded similar corneal SIA values compared with anterior corneal-based measurements.