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Kenneth Marion, Anna Dastiridou, Brian Francis, Vikas Chopra; Assessment and Comparison of Automated Anterior Chamber Metrics between Casia Swept-Source OCT vs Pentacam Scheimpflug Imaging. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3381. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To better understand the automated tools provided by two anterior segment imaging technologies and to determine if light has an effect on Anterior Chamber (AC) Volume
26 normal and 26 POAG participants (n=103 eyes) had both eyes imaged twice using the Tomey Casia SS1000 Swept-Source OCT ‘3D Anterior Segment’ scan (Aichi, Japan) and Oculus Pentacam ‘3D Scan HR’ scan (Arlington, WA) at low light conditions (<0.2fce) at Doheny Eye Centers-UCLA (Figure 1). Gonioscopy showed open angles (grade III-IV on Schaffer scale) for all participants. 29 participants (n=46 eyes) were additionally imaged at normal room light conditions (8.0fce) with the Casia. Sper Light Meter FC–840021 (Scottsdale, AZ) was used to measure light levels at the eye/camera interface.The software tools auto-segment ocular layers and calculate AC Volume (ACV) and Pupil Diameter (PD). Participants were rescanned if mistracing issues were present.Statistics for instrument agreement and correlation (averaged the two acquisitions for each device) and low/normal light metrics using the Casia were determined with correlation coefficients and paired t-tests using MedCalc v184.108.40.206.
The mean±SD Casia ACV/PD was 153.7±45mm3/4.7±1.2mm and Pentacam 148.5±47.2mm3/2.8±0.9mm. ACV/PD correlation between Casia and Pentacam was 0.91/0.56, respectively. There was a statistically significant difference between the ACV for the devices (p=0.01).The mean±SD Casia ACV/PD with the Lights ON in the imaging room was 159.3±36.9mm3/5.9±1.1mm and Lights OFF was 154.7±35.1mm3/3.97±0.81mm. ACV/PD correlation between Casia Lights ON and OFF was 0.92/0.74, respectively. There was a statistically significant difference for the ACV at varied lighting conditions (p=0.04).
Reliable AC volumes can be assessed using both Casia OCT and Pentacam as determined by automated AC metrics analyses. Although statistically significant differences for ACV are found between devices, the differences are small with good correlation with matched lighting conditions. Changes in lighting can affect the ACV & PD values and thus strict lighting conditions should be employed to achieve reliable longitudinal comparisons. Our study underscores the notion that adoption of devices for clinical evaluation for AC parameters will only occur if the devices provide reliably automated analyses.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Figure 1: A) Casia B) Pentacam Volume Scans
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