Glaucoma Diagnosable Using Retinal Nerve Layer Thickness, Minimum Rim Width

Minimum rim width (MRW) and peripapillary retinal nerve fiber layer thickness (RNFLT) measurements perform similarly in discriminating eyes with early to moderate glaucoma from healthy eyes in a diverse population, according to research published in the Journal of Glaucoma.

Researchers prospectively compared the ability of MRW and RNFLT measurements in discriminating eyes with early to moderate glaucoma from healthy eyes in a multiracial Brazilian population. They obtained MRW and RNFLT measurements with optical coherence tomography (OCT) from a single eye of healthy control participants and patients with mild to moderate glaucoma (mean deviation >-12 dB). 

A total of 155 healthy control participants (63% women, 37% men; 69% non-Black, 31% Black) and 118 patients with early to moderate glaucoma (56% women, 44% men; 78% non-Black, 22% Black) were included in the study. Compared with the control group, the patient group was older (mean, 54.4±8.8 vs 64.0±12.2 years; P <.001) and had a larger Bruch membrane opening (BMO) area (1.88±0.38 vs 2.11±0.53 mm²; P <.001).

The researchers found global RNFLT and MRW showed comparable area under the receiver-operating characteristic curve (AUC, 0.93; 95% confidence interval [CI], 0.91–0.96 and 0.93; 95% CI, 0.89–0.96, respectively; P =.973). They also found both parameters demonstrated similar sensitivities at a fixed specificity of 95% (75% for RNFLT vs 74% for MRW; P =.852). 

The team discovered the temporal inferior sector was the best sector for diagnosing glaucoma for both parameters, demonstrating an AUC of 0.93 (95% CI, 0.87–0.96) for RNFLT and 0.91 (95% CI, 0.86–0.95) for MRW (P =.320). 

“Characterizing the diagnostic performance of tests in diverse populations is an important endeavor to reduce misclassifications,” the researchers report. “Although MRW presented a statistically significantly higher diagnostic performance than RNFLT in the nasal superior, temporal, and temporal sectors, our findings suggest that both RNFLT and MRW show comparable diagnostic performance overall in discriminating early to moderate glaucoma from healthy eyes in our population.” 

Limitations of the study included differences in average age and BMO area between the glaucoma and control groups.

Disclosure: This research was supported by Allergan. Multiple study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.