RESUMO
Objectives: This study aims to verify the accuracy of a new calculation formula, Barrett true axial length formula (T-AL), and the optimized lens factor (LF) for predicting postoperative refraction after cataract surgery. Methods: We included 156 Japanese patients who underwent cataract surgery using Clareon monofocal intraocular lenses at our clinic between January 2022 and June 2023. Postoperative spherical equivalent was calculated using subjective refraction values obtained 1 month post-surgery. The LFs were optimized so that the mean prediction error (PE) of each calculation formula was zero (zero optimization). We calculated the mean absolute PE (MAE) to assess accuracy and used a Friedman test for statistical comparisons. The accuracy of T-AL and the optimized LFs was compared with that of the conventional Barrett Universal II formula for ARGOS (AR-B) and OA-2000 (OA-B) with equivalent refractive index. Results: For T-AL, AR-B, and OA-B, the MAEs ± standard deviations were 0.225 ± 0.179, 0.219 ± 0.168, and 0.242 ± 0.206 D, respectively. The Friedman test showed no statistically significant differences among the three groups. The device-optimized LFs were 2.248-2.289 (T-AL), 2.236-2.246 (AR-B), and 2.07-2.08 (OA-B); the corresponding zero-optimized LFs were 2.262-2.287 (T-AL), 2.287-2.303 (AR-B), and 2.160-2.170 (OA-B). Conclusion: There were no significant differences in prediction accuracy among the formulas. However, the accuracy of LF optimization varied by device, with T-AL being closest to the value under zero optimization. This suggests that T-AL is clinically useful for predicting an accurate postoperative refraction without zero optimization.
RESUMO
PURPOSE: To compare the differences in anterior segment parameters between eyes with primary angle closure (PAC) with and without gonioscopically-visualized ciliary body processes (CBP). STUDY DESIGN: Prospective, observational, comparative clinical study. METHODS: Detailed ocular examinations and gonioscopy were performed in 89 eyes of 89 patients with PAC to determine the visibility of the CBP. Anterior chamber depth (ACD), anterior chamber width, lens thickness (LT), lens vault (LV) and pupil diameter were determined using ultrasound biomicroscopy. The lens-axial length factor (LAF) and relative lens position (RLP) were calculated. All parameters were compared between eyes with and without gonioscopically visible CBP (PAC+CBP and PAC-CBP groups) after adjusting for age and gender. The association of the parameters with visible CBP was analyzed by univariate logistic regression analysis. RESULTS: PAC+CBP group included 41 eyes and the PAC-CBP group, 48 eyes. The axial length and ACD were statistically significantly smaller (p = 0.009 and p = 0.005, respectively) and LT, LV and LAF were statistically significantly greater (p = 0.03, p = 0.008 and p = 0.004, respectively) in the PAC+CBP group. In the PAC eyes with glaucoma, the LT, LV and LAF were statistically significantly greater in the PAC+CBP group (p = 0.02, p = 0.001 and p = 0.02, respectively). The LAF had the strongest association with visible CBP in the regression analysis (Odds ratio = 141.70, p = 0.002). CONCLUSION: Gonioscopical visualization of ciliary processes may suggest that anterior segment crowding, especially lens factor is the underlying mechanism in PAC. It may provide a practical gonioscopic examination method for predicting the predominant pathophysiology of PAC.