Comparison of the Accuracy of Total Keratometry and Conventional Keratometry for IOL Power Calculation Based on the New Swept-Source Optical Coherence Tomography Biometry
Department of Ophthalmology, Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, College of Optometry, Peking University Health Science Center, Beijing 100044, China
Abstract:Objective: To compare the accuracy of total keratometry (TK) and conventional keratometry (K) for intraocular lens (IOL) power calculation based on the new swept-source optical coherence tomography biometry. Methods: This was a prospective self controlled study, 29 patients (58 eyes) with binocular age-related cataract were enrolled for the phacoemulsification combined with diffractive trifocal IOL implantation during May 2021 and November 2021 in Peking University People's Hospital. Eyes were assessed using a swept-source optical biometer (IOLMaster 700). Axial length, anterior chamber depth, central corneal thickness, lens thickness, posterior keratometry, TK, and white-to-white corneal diameter were recorded. Emmetropic IOL power was calculated using K and TK in the current standard formulas (SRK/T, Haigis, Holladay2, and Barrett Universal II) and a new formula developed for TK (Barrett TK Universal II). Selected IOL power and predicted refractive outcomes were recorded. Corrected distance visual acuity and postoperative manifest refraction were measured 1 month and 3 months postoperatively. The absolute prediction error, mean absolute error, median absolute error (MedAE), and the percentages of eyes within prediction errors of ±0.25 D, ±0.50 D, ±0.75 D, and ±1.00 D were calculated for all IOL formulas. Wilcoxon signed-rank tests and McNemar's tests were used to analyze the difference. Results: There was strong agreement between K and TK (intraclass correlation coefficient=0.996), with a mean difference of 0.007 D. A relatively lower MedAE values were observed for Haigis and Barrett Universal Ⅱ for TK when compared with K. MedAE from TK was a trend toward larger than that from K in SRK/ T and Holladay2 formulas. A relatively greater proportion of eyes fell within ±0.25 D and ±0.50 D of the predicted postoperative spherical equivalent range in the TK group than in the K group for Barrett Universal Ⅱ formula. Proportion of eyes within ±0.25 D and ±0.50 D of predicted refraction were slightly higher in the K group for SRK/T, Haigis and Holladay2. However, differences in MedAEs, and percentages of eyes within the above prediction errors were not statistically significant. Conclusions: Conventional K and TK for IOL calculation showed strong agreement for refractive prediction for IOL power calculation based on IOLMaster 700, and with a trend toward better refractive outcomes using TK for Barrett Universal Ⅱ formula.
余盈盈,元力,曹晓光,等. 基于新型扫频光源生物测量仪测量的全角膜屈光力和传统角膜屈光力计算IOL度数的准确性比较[J]. 中华眼视光学与视觉科学杂志, 2022, 24(11): 812-819.
Yingying Yu, Li Yuan, Xiaoguang Cao,et al. Comparison of the Accuracy of Total Keratometry and Conventional Keratometry for IOL Power Calculation Based on the New Swept-Source Optical Coherence Tomography Biometry. Chinese Journal of Optometry Ophthalmology and Visual science, 2022, 24(11): 812-819. DOI: 10.3760/cma.j.cn115909-20220505-00186