Primary open-angle glaucoma is known to cause more functional impairment in Black individuals compared with Caucasian individuals, but the reason behind this remains unclear. Looking further into this association, a new study from Duke University found Black patients had a larger visual field variability over time compared with their Caucasian counterparts based on a large, “real-world” clinical population, and this difference remained despite adjustments for age, follow-up duration, number of VFs and socio-economic factors.

In light of the findings, the investigative team suggests this increased variability could lead to a delay in identification of glaucomatous progression in Black patients.

The retrospective observational cohort study used data from 1,103 eyes of 751 Caucasian individuals and 428 eyes of 317 Black participants. Researchers performed linear regression of standard automated perimetry mean deviation values for each eye over time. The participants were seen at the Duke Eye Center and were followed up for around eight years.

The mean rate of MD change was −0.25dB/year for Caucasian individuals and −0.20dB/year for Black individuals.

There was a significant interaction between race and disease severity in the association with VF variability, researchers said. The difference in VF variability was greatest at an MD of approximately −11dB.

When adjusting for zip code based socioeconomic variables, the authors found Black patients had larger VF variability over time compared with Caucasian patients. Additionally, the difference in VF variability between the two groups was greater at lower levels of income and led to a delay in detection of glaucoma progression, the authors said.

“These findings may contribute to worse clinical outcomes that are often seen in Black patients,” researchers said.

The underlying cause of greater VF variability isn’t clear, the investigators noted. Still, they said it was likely that socioeconomic disparities play a role in this difference.

In the study, the association of race with VF variability was clearly influenced by socioeconomic status; however, it is likely that other social factors not considered could further explain the link, researchers said. For example, sleep quality, anxiety and depression may be tied to decreased VF performance reliability, they added.

Stagg B, Mariottoni EB, Berchuck S, et al. Longitudinal visual field variability and the ability to detect glaucoma progression in black and white individuals. Br J Ophthalmol. May 13, 2021. [Epub ahead of print].