It’s become increasingly apparent that bias in the medical field puts non-white patients at a disadvantage. A medical student at St. George’s University in London, for example, found that his training showed disease symptoms only on white skin. “But what will it look like on darker skin?” he asked. He went on to co-publish a handbook on clinical signs in black and brown skin.1
Ophthalmology, as it turns out, faces a similar problem. A recent study evaluated the racial differences in optic nerve head peripapillary capillary density measured by OCT-A in patients with open-angle glaucoma and found that there were indeed racial differences, and these differences had a diagnostic impact.2
The observational, cross-sectional study included 284 eyes of 195 glaucoma patients, and a control group of 103 eyes of 58 healthy subjects. The researchers compared global and sectoral circumpapillary capillary density (cpCD) loss in European-descent (ED) and African-descent (AD) patients, who were of similar age and glaucoma severity. They also evaluated diagnostic accuracy and global circumpapillary retinal nerve fiber layer thickness (cpRNFL) in the two groups.2
Significantly lower cpCD was found in ED than in AD for mild glaucoma. Capillary density loss was greater in all sectors of ED compared with AD subjects, but both racial groups demonstrated a similar sectoral pattern of density loss. Older age was also associated with lower cpCD in both groups.2
The diagnostic accuracy of cpCD was significantly higher for ED compared with AD subjects. Sensitivity at 95% specificity in AD subjects was significantly lower than in ED subjects for cpCD. CpRNFL also had a lower ability for discriminating healthy from glaucotamous eyes in AD compared with ED subjects.2
“Although peripapillary capillary density parameters had good diagnostic accuracy for detecting glaucoma in ED patients, their diagnostic accuracy was only modest in AD patients,” the researchers wrote in their paper. “Diagnostic performance of cpCD is race-dependent and clinicians should be aware that it has poorer performance in AD patients.”2
1. Page S. A medical student couldn’t find how symptoms look on darker skin. He decided to publish a book about it. Washington Post. www.washingtonpost.com/lifestyle/2020/07/22/malone-mukwende-medical-handbook. July 22, 2020. Accessed July 30, 2020.
2. Moghimi S, Zangwill LM, Hou H, et al. Comparison of peripapillary capillary density in glaucoma patients of African and European descent. Ophthalmology Glaucoma. July 18, 2020. [Epub ahead of print].