A number of clinical parameters are useful for diagnosing keratoconus (KC) and monitoring patients before and after treatment. However, it is unclear whether these disease parameters differ between ethnicities. A team of researchers found that KC patients with a European background presented with less severe indicators of disease compared with KC patients of Indian or Asian descent. The results were presented yesterday at the 2019 Association for Research in Vision and Ophthalmology conference in Vancouver.

This observational study recruited KC patients from public and private ophthalmology clinics in Australia, Hong Kong and India. Participants reported ethnicity based on familial origin and were categorized as European, Asian, Indian or other. Each patient underwent a routine clinical examination that included refraction and corneal topography.

The team evaluated 1,472 eyes from 736 KC patients. Of these, 408 (55%) were European, 133 (18%) were Asian, 129 (18%) were Indian and 66 (9%) were other ethnicities. There were 453 (62%) males in total, and more males than females in each group. The age of onset ranged from 12 to 78 years, and the median was in the third decade of life for each ethnicity.

The researchers found no statistical difference in age of onset between European patients compared with each of the other ethnic groups. They note that Indians, however, tended to be older at onset compared with Asians and other ethnicities. They observed that the mean anterior corneal curvature was flatter among Europeans compared with each of the groups, the spherical equivalent was least severe among Europeans compared with other ethnicities and the mean corneal pachymetry was thinner among Indians than Europeans and Asians at the apex and the thinnest location.

“These findings have important clinical implications when interpreting studies from different regions and contribute to the understanding of risk factors and future management strategies of KC,” the study authors conclude. “Further investigation of KC presentation and progression patterns among various ethnic groups is warranted and could be achieved through the development of a global collaborative initiative.”

Sahebjada S, Chan E, McGuinness M, et al. Assessment of clinical parameters by ethnicity in patients with keratoconus: a multi-country study. ARVO 2019. Abstract 321-B0513.