Abstract
Purpose :
To evaluate the diagnostic performance of swept-source optical coherence tomography (SSOCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan) for angle closure detection, in comparison with gonioscopy.
Methods :
Prospective observational community based study of 2027 participants. All phakic subjects aged ≥50 years, with no known history of glaucoma, intraocular surgery or trauma, were recruited from a community polyclinic in Singapore. Gonioscopy was performed by single ophthalmologist. The SSOCT 3-dimensional angle scans, which obtain radial scans for the entire circumference of the angle, were performed under dark conditions and 128 scans were analyzed by a single examiner masked to the subject’s clinical details. Gonioscopic angle-closure was defined as non-visibility of posterior trabecular meshwork for at least 2 quadrants, while on SS OCT images, angle closure was defined as contact between the iris and any part of the angle wall anterior to the scleral spur at different cut off values of circumferential angle closure extension (≥35%, ≥50% and ≥75%). Only right eyes were taken for analysis and the area under the curve (AUC) receiver operating characteristic (ROC) was generated to assess the performance of SSOCT in detecting angle closure.
Results :
1907 right eyes were finally included in the analysis after excluding poor quality SSOCT scans. The prevalence of angle closure on gonioscopy and SSOCT was 7.15% and 26.12%, respectively. The AUC for angle closure detection using manual grading in SSOCT images was 0.81 (95% confidence interval (CI), 0.77-0.84) at a cut off value of ≥35%, and 0.80 (95% CI, 0.76-0.84) and 0.76 (95% CI 0.72-0.80) at ≥50% and ≥75%, respectively. The criteria of ≥ 35% of circumferential angle closure had a sensitivity of 82.52% (95% CI 75.28%-88.36%) and a specificity of 78.46 % (95% CI, 76.46%-80.36%) for detecting gonioscopic angle closure.
Conclusions :
In this large community based study, SSOCT had good performance for angle closure detection, with gonioscopy as the reference standard. The cut off value of ≥35% showed the best accuracy for angle closure detection.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.