Automated Gonioscopy, A Promising Technology for Angle Imaging

Automated gonioscopy is a useful angle imaging technique that provides moderate agreement on most clinically relevant categories, according to study results published in the Journal of Glaucoma. 

Researchers evaluated the interrater agreement of iridocorneal angle (ICA) features in a real-life clinical setting. Adult patients from 2 testing centers underwent automated gonioscopy. One picture per quadrant was chosen for randomization from each eye. The pictures were analyzed and rated by 4 masked glaucoma specialists for angle opening width, Shaffer gradings, Spaeth gradings, and other findings. The investigators performed Fleiss’ κ statistics to examine interrater agreement.

The study included 50 participants (mean age 59.8±20.8 years, 96% White). Half had been previously diagnosed with glaucoma, 7 had ocular hypertension (14%), 6 had suspected primary angle closure (12%), 1 had angle recession (2%), 1 had amyloidosis (2%), and the remaining 10 (20%) were considered healthy. Most of the study population was phakic (n=34; 68%), 8 (16%) had a history of prior glaucoma surgery, and 10 (20%) had received some form of laser intervention (e.g. peripheral iridotomy or laser trabeculoplasty).

Researchers found a moderate agreement on angle opening, angle width, presence of angle vessels, and peripheral anterior synechiae (κ=0.435, 0.511, 0.558, 0.488, respectively; P <.01). They observed fair agreement with regard to Shaffer grading, site of iris root insertion, angle pigmentation features, and the presence of iris processes.

The configuration of peripheral iris had poor agreement from a 2-dimensional picture. A subset analysis of higher quality pictures appeared to show an increased agreement on pigment; however, it did not further improve the overall agreement on angle opening status.  

“Automated gonioscopy is a promising angle imaging method which allows for swift documentation and longitudinal analysis of angle findings,” according to the researchers. “Agreement between raters was moderate on relevant angle features, particularly in clinically relevant binary items such as angle status or PAS.”

Limitations of the study include a relatively small and homogenous population in terms of iris color and ethnicity.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Correia Barão R, Cutolo C, Tanito M, et al. Agreement analysis on angle characteristics with automated gonioscopy. J Glaucoma. Published online December 1, 2021. doi:10.1097/IJG.0000000000001940