Abstract
Purpose: :
To compare the diagnostic performance of EyeCam (Clarity Medical Systems, Pleasanton, CA) and Anterior Segment Optical Coherence Tomography (Visante ASOCT, Carl-Zeiss Meditec, Dublin, USA) in detecting angle closure, using gonioscopy as the reference standard.
Methods: :
Ninety-eight phakic eyes of 98 patients were recruited from a glaucoma clinic. All subjects underwent gonioscopy, EyeCam angle imaging and ASOCT. A single masked examiner, performed gonioscopy in the dark room in all cases and classified the anterior chamber angle as closed if the posterior trabecular meshwork was not seen in that particular quadrant. EyeCam and OCT images were graded by another examiner, masked to gonioscopy findings. A closed angle in a particular quadrant was defined as any contact between the iris and angle wall anterior to the scleral spur on the ASOCT images and if the posterior trabecular meshwork was not seen in the EyeCam images. An eye was diagnosed as having angle closure if ≥ 2 quadrants were closed. Agreement and area under the receiver operating characteristic curves (AUC) between the two methods were evaluated, with gonioscopic reference standard.
Results: :
The majority of study subjects were Chinese (69/98, 70%) with a mean age of 60.6 (SD - 12.5) years. Gonioscopy, EyeCam and ASOCT diagnosed closed angles in 39/98 (40%), 40/98 (41%) and 56/97 (58%) eyes respectively. The agreement for angle closure diagnosis between gonioscopy and EyeCam was good (kappa=0.894) while that between gonioscopy and ASOCT was moderate (kappa=0.580). AUC for EyeCam was 0.978 (95% CI 0.926-0.997) and that for ASOCT was 0.864 (95% CI 0.786-0.942). EyeCam performed significantly better than ASOCT (AUC - 0.978 vs 0.864, p = 0.01) using gonioscopy as the reference standard.
Conclusions: :
The ability of the EyeCam to discriminate angle closure was better than ASOCT when gonioscopic grading was used as a reference standard. The agreement between the two imaging modalities was moderate.
Keywords: imaging/image analysis: clinical • anterior segment • trabecular meshwork