Cell count differences in diabetic-related corneas suggests more studies

Take-Home Message: An age-stratified analysis of endothelial cell count in diabetic and non-diabetic corneas found no statistically significant difference between the groups. Since diabetes may damage the inner layer of the cornea, other variables that affect cell health must also be evaluated.

By Nancy Groves; Reviewed by Prabjot Channa, MD

Bronx, NY-A statistically significant difference in the endothelial cell count in diabetic and non-diabetic corneas disappeared when the data from a retrospective analysis were stratified by age groups, suggesting the need for further study to determine if other factors contribute to differences in endothelial cell health.

“Evidence regarding the effect of diabetes on the corneal endothelium is still not entirely clear,” said Prabjot Channa, MD, lead author of a recent study. “There have been studies done in the past with conflicting outcomes.”

Dr. Channa is assistant clinical professor, Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, New York.

Endothelial cell density is often used as a measure to predict whether a donor cornea is suitable for transplant, and diabetes has been shown to adversely affect the cornea, as well as other organ tissues in the body, said Dr. Channa. It has been suggested that oxidative and osmotic stress from excessive activation of the polyol pathway and accumulation of sorbitol may play a role in corneal endothelial damage in patients with diabetes, and the researchers hoped to learn more about the possible relationship between the disease and corneal cell changes.

Donor data

Dr. Channa and colleagues obtained de-identified cornea donor data from July 2013 to June 2014 from the Lions Eye Institute for Transplant & Research, Tampa, FL. Diabetic and non-diabetic donors were distinguished by medical history and medication lists. Data from 1,486 diabetic corneas and 2,488 non-diabetic corneas were analyzed; the mean age of the diabetic group was 57.27, and the mean age for the non-diabetic group was 53.23.

Although the initial analysis between the two groups indicated a statistically significant difference in endothelial cell count, age-stratified groups did not. This discrepancy between the overall results and the age-stratified results may be due to a difference in distribution of ages between the diabetic and nondiabetic groups. There were a larger number of non-diabetic corneas in the younger age groups, Dr. Channa said.

“This study is exciting because it provides a new perspective on how diabetic donor tissue can be evaluated,” Dr. Channa said. “But these findings are initial. Going forward, there are many more questions that need to be answered. There may be more variables other than endothelial cell count that matter.

“It will be important to look at other factors that can affect cell health–such as the duration and nature of diabetes, Hg A1C in terms of glycemic control, and the age of the patient,” she added. “Criteria other than endothelial cell density that need to be considered include morphometric analysis. Measurements, such as corneal thickness, pleomorphism, polymegathism, and coefficient of variation, are more sensitive in assessing the health of the endothelium in terms of function and integrity. Such data may reveal early changes not measured by cell density alone.”

Prabjot Channa, MD

E: pchanna@montefiore.org

This article was adapted from Dr. Channa’s presentation at the 2015 meeting of the Association for Research in Vision and Ophthalmology. Dr. Channa did not report any relevant financial disclosures in regard to this article.