Abstract
PurposeTo assess the precision (repeatability and reproducibility) of ocular parameters measured by the Tomey OA-2000 biometer, and to compare them with those measured by the IOLMaster.MethodsIn this prospective study, the right eyes of 108 healthy subjects were included. Three consecutive scans were obtained by 2 observers using the Tomey OA-2000, and in the same session one observer used the IOLMaster (version 5.4.4.0006) for the measurements. About 1 week later, 3 scans were obtained by one observer using the Tomey OA-2000. The axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), keratometer readings, pupil diameter (PD) and corneal diameter (CD) values measured by the Tomey OA-2000 and IOLMaster were analyzed. The coefficient of variation (CoV), intraclass correlation coefficient (ICC), within subject standard deviation (Sw) and 2.77Sw were calculated to assess the repeatability and reproducibility. The paired t test and Bland-Altman plots were used to analyze the differences and agreements of parameters measured by the two devices, respectively.ResultsIntraobserver repeatability, and interobserver and intersession reproducibility of the AL, CCT, ACD, LT, Kf, Ks, Km, PD and CD values measured by the Tomey OA-2000 biometer showed a CoV of less than 1% except that for PD, and an ICC of more than 0.97 except that for PD and CD. The AL, Kf, Ks, Km and CD values measured by the Tomey OA-2000 were 0.058 ± 0.094 mm, 0.088± 0.150 diopters (D), 0.163 ± 0.170 D, 0.127 ± 0.117 D and 0.171 ± 0.217 mm lower than those measured by the IOLMaster, respectively (all Ps < 0.05). However, the ACD values from the two devices were comparable (P = 0.169). The 95% linite of agreement (LoA) of the AL, ACD, CD and all keratometer readings were no more than 0.24 mm, 0.14 mm 0.60 mm and 0.5 D, respectively.ConclusionExcept for the PD and CD, the ocular parameters measured by the Tomey OA-2000 were highly repeatable and reproducible. Except for the CD value, there was good agreement of ocular parameters measured by the Tomey OA-2000 and the IOLMaster in healthy eyes.
Highlights
Accurate ocular biometry is essential for predicting the intraocular lens (IOL) power before refractive and cataract surgery[1]
Intraobserver repeatability, and interobserver and intersession reproducibility of the axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), Kf, Ks, Km, pupil diameter (PD) and corneal diameter (CD) values measured by the Tomey OA-2000 biometer showed a coefficient of variation (CoV) of less than 1% except that for PD, and an intraclass correlation coefficient (ICC) of more than 0.97 except that for PD and CD
The AL, Kf, Ks, Km and CD values measured by the Tomey OA-2000 were 0.058 ± 0.094 mm, 0.088± 0.150 diopters (D), 0.163 ± 0.170 D, 0.127 ± 0.117 D and 0.171 ± 0.217 mm lower than those measured by the IOLMaster, respectively
Summary
Accurate ocular biometry is essential for predicting the intraocular lens (IOL) power before refractive and cataract surgery[1]. For cataract surgery, precise ocular biometry can decrease refractive error and achieve the predicted postoperative outcome. Ultrasound-based axial length (AL) and anterior chamber depth (ACD, from corneal epithelium to anterior surface of crystalline lens) measurements have been the benchmark for a long period of time. The precision of the IOLMaster in both cataract biometry[5,6,7] and the study of refractive error evaluation[8, 9] set a new standard for ocular biometry. In IOLMaster 500 and older models, such as the model(software version: 5.4.4.0006) used in the present study, the corneal, crystalline lens or retinal thickness are not evaluated[10]. Realignment is required before each parameter is measured[11]
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