Abstract
Purpose :
Reliable measurement of anterior segment parameters is pertinent to the diagnostic evaluation of primary angle closure and the planning of anterior segment surgery. This study measured various anterior segment parameters and their test-retest variabilities obtained from two new anterior segment SS-OCT – the ANTERION and the CASIA II.
Methods :
38 subjects, 18 patients with primary angle closure and 20 healthy participants with open angles, had ANTERION and CASIA II imaging in the same visit using the same scan pattern (6 evenly-spaced radial scans across the anterior segment). One randomly selected eye of each subject was imaged by each instrument twice and the within-instrument, test-retest variabilities of angle open distance (AOD500), trabecular-iris space area (TISA500), scleral spur-scleral spur distance (SSD), pupil size (PS), and anterior chamber depth (ACD) were measured. All parameters were automatically generated from the SS-OCT instruments except for AOD, TISA and SSD, which were computed after the scleral spur was located by a single blind observer.
Results :
The mean age was 54.7±15.8 years (range: 26-75 years). There were significant differences between ANTERION and CASIA II measurements; the SSD, PS, and ACD were smaller whereas AOD500 and TISA500 were greater in ANTERION compared with CASIA II (Table 1). The within-instrument, test-retest differences in SSD, PS, AOD500, TISA500 were similar between ANTERION and CASIA II (p≥0.328, linear mixed modeling with adjustment of multiple meridian measurements within an eye). The respective repeatability coefficients and their 95% confidence intervals are shown in Table 2. The repeatability coefficient of ACD was smaller for CASIA II (0.016mm, 95% CI: 0.013-0.020) than ANTERION (0.031mm, 95% CI: 0.025-0.040).
Conclusions :
Although there were systematic differences between ANTERION and CASIA II measurements, both instruments were reliable for measurement of anterior segment parameters.
This is a 2020 ARVO Annual Meeting abstract.