Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography

Abstract

PurposeTo assess the interdevice agreement between swept-source Fourier-domain and time-domain anterior segment optical coherence tomography (AS-OCT).MethodsFifty-three eyes from 41 subjects underwent CASIA2 and Visante OCT imaging. One hundred eighty–degree axis images were measured with the built-in two-dimensional analysis software for the swept-source Fourier-domain AS-OCT (CASIA2) and a customized program for the time-domain AS-OCT (Visante OCT). In both devices, we examined the angle opening distance (AOD), trabecular iris space area (TISA), angle recess area (ARA), anterior chamber depth (ACD), anterior chamber width (ACW), and lens vault (LV). Bland-Altman plots and intraclass correlation (ICC) were performed. Orthogonal linear regression assessed any proportional bias.ResultsICC showed strong correlation for LV (0.925) and ACD (0.992) and moderate agreement for ACW (0.801). ICC suggested good agreement for all angle parameters (0.771–0.878) except temporal AOD500 (0.743) and ARA750 (nasal 0.481; temporal 0.481). There was a proportional bias in nasal ARA750 (slope 2.44, 95% confidence interval [CI]: 1.95–3.18), temporal ARA750 (slope 2.57, 95% CI: 2.04–3.40), and nasal TISA500 (slope 1.30, 95% CI: 1.12–1.54). Bland-Altman plots demonstrated in all measured parameters a minimal mean difference between the two devices (−0.089 to 0.063); however, evidence of constant bias was found in nasal AOD250, nasal AOD500, nasal AOD750, nasal ARA750, temporal AOD500, temporal AOD750, temporal ARA750, and ACD. Among the parameters with constant biases, CASIA2 tends to give the larger numbers.ConclusionsBoth devices had generally good agreement. However, there were proportional and constant biases in most angle parameters. Thus, it is not recommended that values be used interchangeably.

Intradevice Repeatability and Interdevice Agreement of Ocular Biometric Measurements: A Comparison of Two Swept-Source Anterior Segment OCT Devices

“…The fact that the CASIA and ANTERION both demonstrated excellent intradevice measurement repeatability is unsurprising given that this metric has effectively plateaued since the popularization of Fourier-domain OCT technology. [19][20][21][22] What is surprising, however, is that interdevice agreement of measurements between the CASIA SS-1000 and ANTERION was equal to or higher than metrics reported by previous studies comparing other AS-OCT devices. Comparisons of measurements from the swept-source Tomey CASIA2 AS-OCT device with the time-domain Zeiss Visante (Carl Zeiss Meditec) or Heidelberg Spectralis reported mean ICC values of 0.78 and 0.78, respectively, for AOD500, and 0.81 and 0.78, respectively, for TISA500.…”

“…Comparisons of measurements from the swept-source Tomey CASIA2 AS-OCT device with the time-domain Zeiss Visante (Carl Zeiss Meditec) or Heidelberg Spectralis reported mean ICC values of 0.78 and 0.78, respectively, for AOD500, and 0.81 and 0.78, respectively, for TISA500. 21,22 These lower ICC values may be related to the fact that the Visante is a time-domain device with relatively poor image resolution and the Spectralis uses a shorter wavelength laser that is primarily intended for posterior segment imaging. The improvement in interdevice agreement translates into measurements that are nearly interchangeable between the ANTERION and CASIA for all parameters except SSA500.…”

“…Comparing measurements within and between these two devices is crucial since previous AS-OCT devices have demonstrated variable interdevice measurement agreement, ranging from poor to excellent. [19][20][21][22] We also assess the effect of image averaging, a feature that is unique to the ANTERION, on intradevice measurement repeatability.…”

Comparison of composite and segmental methods for acquiring optical axial length with swept-source optical coherence tomography

“…A second generation anterior segment swept-source optical coherence tomography (AS-OCT) was recently developed [10][11][12] . This novel, but commercially-available, AS-OCT system has an improved scan rate, depth capacity, and density assessment, allowing for sharper images of the anterior and posterior surfaces of the cornea, crystalline lens, and IOL.…”

“…This novel, but commercially-available, AS-OCT system has an improved scan rate, depth capacity, and density assessment, allowing for sharper images of the anterior and posterior surfaces of the cornea, crystalline lens, and IOL. As a result, corneal thickness, ACD, aqueous depth (AQD: the distance between the corneal endothelium and the lens surface), and lens thickness can be automatically measured using AS-OCT with good repeatability and reproducibility [10][11][12] . Moreover, a newly introduced optical biometer that is also based on swept-source optical coherence tomography (SS-OCT) has been shown to generate repeatable and reproducible measurements [13][14][15][16] .…”