Comparison between a New Optical Biometry Device and an Anterior Segment Optical Coherence Tomographer for Measuring Central Corneal Thickness and Anterior Chamber Depth

Jinhai Huang,Fangjun Bao,Hao Chen,Weicong Lu,Qinmei Wang,Chengfang Wang,Xinxin Yu,Giacomo Savini

doi:10.1155/2016/6347236

Abstract

Purpose. To compare between a new optical biometer (AL-Scan, Nidek Co., Aichi, Japan) and an anterior segment optical coherence tomographer (Visante AS-OCT, Carl Zeiss Meditec, Dublin, USA) for measuring central corneal thickness (CCT), anterior chamber depth (ACD), and aqueous depth (AD). Methods. Sixty-three eyes of 63 normal subjects were examined with AL-Scan and Visante AS-OCT in this prospective study. One eye per subject was measured three times with both devices to record their CCT, ACD, and AD. All procedures were performed by the same operator. Agreement between the two devices was assessed using paired t-tests, Bland-Altman plots, and 95% limits of agreement (LoA). Results. The mean CCT, ACD, and AD measured by AL-Scan were 538.59 ± 27.37 μm, 3.70 ± 0.30 mm, and 3.16 ± 0.30 mm, respectively. The mean values obtained by the Visante OCT were 536.14 ± 26.61 μm for CCT, 3.71 ± 0.29 mm for ACD, and 3.17 ± 0.29 mm for AD. The mean CCT by the AL-Scan was higher than that obtained by the Visante AS-OCT (difference = 2.45 ± 6.07 μm, P < 0.05). The differences in ACD and AD measurements were not statistically significant. The 95% LoA of CCT, ACD, and AD were between −9.44 and 14.35 μm, −0.15 and 0.12 mm, and −0.15 and 0.12 mm, respectively. Conclusions. Since these two devices were comparable for measuring CCT, ACD, and AD, their results can be interchangeably used in the clinic.

Highlights

As cataract and refractive surgery are increasingly performed, the surgeons’ skills as well as the precision of ocular measurements are important in order to satisfy patients’ expectations
Measurements of the anterior chamber depth (ACD), which is defined as the distance from the corneal epithelium to the anterior surface of the crystalline lens, and the aqueous depth (AD), which is defined as the distance from the corneal endothelium to the anterior surface of crystalline lens, have many clinical applications [7]
The mean Central corneal thickness (CCT), ACD, and AD measured by axial length (AL)-Scan were 538.59 ± 27.37 μm, 3.70 ± 0.30 mm, and 3.16 ± 0.30 mm, respectively

Summary

Introduction

As cataract and refractive surgery are increasingly performed, the surgeons’ skills as well as the precision of ocular measurements are important in order to satisfy patients’ expectations. Central corneal thickness (CCT) is critical in designing vision correction surgeries such as laser in situ keratomileusis (LASIK), as well as in glaucoma diagnosis and other corneal diseases [1,2,3,4,5,6]. Anterior segment optical coherence tomography (Visante AS-OCT, Carl Zeiss Meditec, Dublin, CA, USA) has been clinically used for several years for anterior segment measurement and has high resolution. It is based on low coherence interferometry and uses the light source of a 1310 nm superluminescent light-emitting diode. The Visante AS-OCT is widely used to measure the corneal thickness and ACD. The AL-Scan is a newly introduced optical biometer that can measure six parameters within 10 seconds, including CCT, Journal of Ophthalmology

Methods

Results

Conclusion