The research was published in last month's Hypertension: Journal of the American Heart Association (March 24).
It has been assumed for some time that blacks have an excess risk of hypertensive retinopathy, but few existing studies have made this connection and studies were not based on patient groups representative of a general population.
Assistant professor Tien Yin Wong and his colleagues from Singapore National Eye Centre designed a community-based study and examined the risk factors that may account for possible racial differences in the rate of retinopathy.
The study was of 15,792 women and men, aged 45-65 years-old at time of recruitment in 1987-1989, though exclusions because of health problems such as diabetes Ð which complicates the assessment of retinopathy Ð left 1,860 blacks and 7,874 whites, aged 49-73 in the group.
The prevalence of retinopathy was nearly twice as high in blacks than in whites (7.7 per cent versus 4.1 per cent), with the prevalence of retinopathy in black people reduced by about 53 per cent after adjusting the findings to account for the severity of hypertension and other cardiovascular risk factors.
'We found that differences in blood pressure explained about half of the excess prevalence of retinopathy in African Americans,' said Professor Wong. 'Controlling hypertension in African Americans is probably one method to reduce the higher prevalence of retinopathy.'
Researchers in the US claim they have shown that hypertensive retinopathy is twice as common in blacks as in whites.