AS-OCT Shows Usefulness for Detecting Gonioscopically Narrow Angles

On anterior segment optical coherence tomography (AS-OCT), the angle opening distance at 750 μm (AOD750) parameter has the highest diagnostic accuracy for detecting gonioscopically narrow angles among individuals aged 60 years or older, according to research published in Ophthalmology Glaucoma. 

Researchers conducted a population-based cross-sectional study to evaluate the diagnostic accuracy of AS-OCT screening for detecting gonioscopically narrow angles. The team selected participants from a door-to-door population census and performed AS-OCT, posterior segment OCT, and intraocular pressure (IOP) measurement on 12,633 individuals. Among 3116 participants who met referral criteria, 858 underwent a comprehensive eye exam, including gonioscopy, which was performed by a glaucoma specialist.

The investigators evaluated the sensitivity and specificity of 5 semi-automated AS-OCT parameters relative to gonioscopically narrow angles, which the study defined as the absence of visible trabecular meshwork for 180° or more on non indentation gonioscopy.

The area under the receiver-operating characteristics curves (AUROC) ranged from 0.85 to 0.89 for the 5 AS-OCT parameters, according to the report, demonstrating that each offered good diagnostic accuracy for predicting gonioscopically narrow angles. The AOD750 had the best diagnostic accuracy, with a sensitivity of 87% (95% CI, 75%-96%) and specificity of 77% (95% CI, 71%-83%) at a cutpoint of 367 μm, and a sensitivity of 65% (95% CI, 54%-74%) when the specificity was constrained to 90% (cutpoint 283 μm).

Although AOD750 demonstrated the best ability to determine gonioscopically narrow angles, the researchers question its role in clinical practice.

“The clinical utility of diagnosing gonioscopically narrow angles remains unclear given previous studies that have shown that the majority of eyes with narrow angles do not progress to vision-threatening disease,” according to the study authors.

Study limitations include the use of only 1 temporal AS-OCT scan of each eye, potential distortion of the AS-OCT images due to refraction at the air-cornea interface, and inclusion of individuals from only 1 geographic region.