Comparison of corneal surgically induced astigmatism calculations as measured by two biometric devices, and by standard anterior vs total keratometric measurements.

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.
Ophthalmology Department, Shaare Zedek Medical Center, Jerusalem, Israel.
Retrospective, consecutive case series.
The medical records of patients who had undergone cataract surgery through a 2.4 mm temporal clear corneal incision by a single surgeon between 3/2018 and 11/2020 were retrospectively reviewed. Patients for whom there were preoperative and postoperative keratometry measurements by 2 biometric devices, optical low-coherence reflectometer (OLCR) and swept-source optical coherence tomography (SS-OCT), were identified. Corneal SIA (mean vector value) was calculated by vector analysis for 3 groups: SS-OCT(K), SS-OCT(TK) and OLCR(K). Bivariant analyses were applied for comparisons.
One-hundred forty-seven eyes of 123 patients (73 OD and 74 OS) were enrolled in the study. The OD corneal SIA values were 0.09 D @ 136°, 0.09 D @ 141°, and 0.07 D @ 123°, for the SS-OCT(K), SS-OCT(TK), and OLCR, respectively. The respective OS corneal SIA values were 0.13 D @ 120°, 0.11 D @ 123°, and 0.08 D @ 120°. There were no 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 three groups.
Corneal SIA values were low (0.07 to 0.13 D) and similar for the SS-OCT and the OLCR biometric devices with standard keratometry. Total keratometry measurements yielded similar corneal SIA values compared to anterior corneal-based measurements.