Agreement of Anterior Segment Parameter Measurements With CASIA 2 and IOLMaster 700

Abstract

Purpose: To compare the difference and agreement in central corneal thickness (CCT), keratometry (K), anterior chamber depth (ACD), aqueous depth (AQD), and lens thickness (LT) measured with CASIA 2 and IOLMaster 700 in patients with cataract.

Methods: A total of 81 patients with cataract (81 eyes) scheduled for phacoemulsification were prospectively collected from March to May, 2020 in the cataract department of Zhongshan Ophthalmic Center, Sun Yat-sen University, including 43 males and 38 females with age of 61.5 ± 10.6 years. CCT, anterior K_f, anterior K_s, real K_f, real K_s, ACD, AQD, and LT were measured with CASIA 2 and IOLMaster 700. Paired t-test, intraclass correlation coefficients (ICCs), 95% limit of agreement (95% LoA), and Bland-Altman plots were performed and used to analyze the difference and agreement between the two devices.

Results: There was no statistically significant difference in anterior K measurement with the CASIA 2 (44.3 ± 1.66 mm) and IOLMaster 700 (44.31 ± 1.67 mm, P = 0.483). Differences among the CCT, anterior K_f, real K_f, real K_s, ACD, AQD, and LT measured by the two instruments were statistically significant (P < 0.001). The ICCs of CCT, anterior K_f, anterior K_s, real K_f, real K_s, ACD, AQD, and LT measurements between the two devices were 0.892, 0.991, 0.991, 0.827, 0.817, 0.937, 0.926, and 0.997, respectively. The 95% LoA between CASIA 2 and IOLMaster 700 was -30.06 to 0.43 μm for CCT, -0.3 to 0.48 D for anterior Kf, -0.46 to -0.43 D for anterior Ks, -1.49 to -0.49 D for real Kf, -1.62 to -0.49 D for Real Ks, -0.03 to 0.24 mm for ACD, 0.04 to 0.25 mm for AQD, and -0.06 to 0.09 mm for LT.

Conclusion: Anterior K_f, anterior K_s, ACD, AQD, and LT have excellent agreement between the two devices. CCT, real K_f, and real K_s have moderate agreement between the two devices. It is recommended to use anterior K_f, anterior Ks, ACD, AQD, and LT interchangeably between CASIA 2 and IOLMaster 700.

Keywords: CASIA 2; IOLMaster 700; agreement; anterior segment optical coherence tomography; anterior segment parameters.

Figure 1

Bland-Altman plots of cornea curvature measurement with CASIA2 and IOL-mater700. Kf, flat keratometric power; Ks, steep keratometric power. (A) Anterior Kf, (B) Anterior Ks, (C) Real Kf, and (D) Real Ks. Black dotted lines indicate the bias between both devices and red dotted lines indicate the 95% confidence interval for the difference.

Figure 2

Bland-Altman plots of (A) ACD, (B) AQD, (C) CCT, and (D) LT measurements with CASIA2 and IOL-Master 700. ACD, anterior chamber depth; AQD, aqueous depth; CCT, central cornea thickness; LT, lens thickness.