Remote Grading of the Anterior Chamber Angle Using Goniophotographs and Optical Coherence Tomography: Implications for Telemedicine or Virtual Clinics

Abstract

PurposeTo evaluate the agreement and accuracy of grading goniophotographs and anterior segment optical coherence tomography (AS-OCT) results for assessment of the anterior chamber angle, and elicit factors driving concordance between perceived grade and ground truth.MethodsThree clinicians evaluated the goniophotographs and AS-OCT results of 75 patients. Graders' impressions of the angle grade, trabecular pigmentation, and iris contour were compared with the ground truth gonioscopic examination result when physically performed by a senior optometrist. Percentage agreement and kappa statistics were calculated. Binary logistic regression was used to elicit factors for accurate grading.ResultsExact angle matches and binary (open or closed) evaluations were above guessing rate for all graders. There was a systematic bias toward underestimating the angle structure across all graders, especially at the superior angle, by approximately 1 ordinal unit. Kappa statistics showed fair-moderate agreement for exact (0.387–0.520) and binary (0.347–0.520) angle evaluations. Agreement was unchanged when using a multimodal approach (0.373–0.523). Factors driving concordance were primarily related to the extremes of the anterior chamber angle configuration (shallow or deep structures, and iris contour). However, prediction models did not fully explain the levels of concordance with the ground truth (maximum R2 amongst models 0.177).ConclusionsAlthough moderate agreement between graders and ground truth could be obtained under binary evaluations, angle grades were generally underestimated. Factors affecting concordance were primarily the extremes of the ground truth angle and iris contour.Translational RelevanceWe highlight factors affecting accuracy of grading goniophotography and AS-OCT images of the anterior chamber angle.

Modeling of gonioscopic anterior chamber angle grades based on anterior segment optical coherence tomography

“…The precision could be increased when quadrants were divided to groups of open angle and angle closure compared with the three-group model. Agreement was also fair to moderate in multi-grade scheme however slightly higher with the open-closed scheme in the work of Phu et al [31], who compared the ACA structure using gonioscopy and AS-OCT. Even so, the advantage of the additional MA group demonstrated in this study could not be underestimated.…”

Intraobserver and interobserver agreement among anterior chamber angle evaluations using automated 360-degree gonio-photos

“…Thus, each ophthalmologist was asked to individually evaluate the width of Scheie’s angle and pigmentation gradings [ 15 ] and the presence or absence of PAS and Sampaolesi line [ 9 ]. For analysis, we modified the original Scheie’s grading systems by labeling 0 (wide or 0), 1 (I), 2 (II), 3 (III), and 4 (IV) [ 18 ]. Then, we analyzed the interobserver agreements for angle evaluations using the gonioscopic photos.…”

Anterior Chamber Angle Assessment Techniques: A Review

“…The importance of telemedicine and the use of virtual ophthalmology has recently also increased, especially in the setting of the so-called COVID-19 era [134]. Gonio-photographs and AS-OCT imaging have been already used for remote evaluation and screening of angle closure, with encouraging results [135]. Although these techniques are likely to require further improvements, they may be considered as auxiliary solutions, in a time of social distancing.…”