This study examined whether the higher rate of blindness due to glaucoma among black Americans might be due in part to undertreatment for this disorder. They used a 5% random sample of Medicare beneficiaries.

The (adjusted) rates of surgical treatment of glaucoma by census division reveal that, across the country, the rate of treatment is significantly higher for blacks than whites and ranges between 1.99 and 2.82 times higher for all regions except the Mountain region (RR=1.23, 95% confidence interval=0.53 to 3.22). Overall, blacks received surgical treatment 2.19 times more frequently than whites.

Based on the estimate that blacks have four times the rate of glaucoma of whites, the expected rate of treatment for blacks if they had received the same rate as whites was compared to the observed rate of treatment. Overall, the observed treatment rate for blacks was 45% lower than the expected rate (95% confidence interval=24% to 61%).

The authors conclude that these data support the hypothesis that blacks with glaucoma are under-treated. They note that economic and social factors may contribute to the observed racial differences in treatment relative to the prevalence of disease and suggest the possibility that "physicians may alter their practice pattern overtly of subconsciously on the basis of the patient's racial and economic characteristics".