Comparison of preoperative and postoperative measurements of optical low-coherence reflectometry biometry and assessment of its refractive predictability

Abstract

Purpose: To compare the preoperative and postoperative measurements of optical low-coherence reflectometry (OLCR) biometry and assessment of its refractive predictability.

Methods: A total of 114 eyes of 102 patients who underwent cataract treatment were prospectively examined. The axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), K (keratometry) 1, K2, K average (KAVE) and K astigmatic (KAST) values were recorded using Lenstar LS 900 (Haag-Streit, Koeniz, Switzerland) OLCR device. The IOL (intraocular lens) power was measured based on the SRK/T formula. The cases were divided into three subgroups according to AL (Group 1: AL < 22 mm, Group 2: 22 mm ≤ AL < 24 mm, Group 3: 24 mm ≤ AL). The mean absolute error (MAE) calculated for each eye.

Results: The right eyes of 45 patients (44.1%), left eyes of 45 patients (44.1%), and both eyes of 12 patients (11.7%) were examined. The average AL in the preoperative period was 23.19 ± 1.01; it was 23.20 ± 0.99 in the postoperative period (p > 0.05). A significant deepening was detected in the postoperative ACD (preop 2.76 ± 0.38 mm, postop 3.81 ± 0.46 mm, p < 0.001). CCT was measured as 521.4 ± 36.3 µm in the preoperative period and as 530.8 ± 42.8 (p > 0.05) µm in the postoperative period. The average mean absolute error (MAE) was measured as 0.48 ± 0.41 D, whereas refractive error was - 0.081 ± 0.67 D. The MAE distribution of cases was found to be ≤ 1.5 D 109 (95.6%) eyes, and ≤ 2.0 D in 114 (100%) eyes. MAE values according to AL of the cases were calculated as 0.71 ± 0.83 D in group 1, 0.49 ± 0.43 D in group 2 and 0.41 ± 0.36 D in group 3 (p > 0.05).

Conclusion: When the measurement and refractive results of the OLCR biometry were evaluated, it was observed that there was a very satisfactory result and a predictable device compatible with the current literature. The SRK/T formula, one of the new generation formulas, has shown high MAE and RE results in eyes with AL ≤ 22 mm, although not statistically significant. Other new generation formulas should be tried in these eyes.

Keywords: Axial length; Biometry; Keratometry; Lenstar; Mean absolute error.