Age, disease duration tied to corneal changes in diabetes

Diabetes seems to alter corneal endothelial cell morphology, particularly among older patients with long-standing disease, a recent study has found.

Researchers conducted a retrospective cross-sectional analysis of 511 type 2 diabetes (T2D) patients, corresponding to 1,022 eyes. A noncontact specular microscope and a Pentacam Scheimpflug camera were used to measure endothelial cell density (ECD), variation in endothelial cell size (CV), the percentage of hexagonal cells, and central corneal thickness (CCT). A parallel group of 900 controls (1,799 eyes) was also included.

Corneal parameters differed significantly across all age groups. ECD (p=0.023) and hexagonality (p=0.03), for example, were significantly lowered in diabetics, while CV and CCT were higher (p=0.000 for both).

Stratifying according to disease duration, the researchers found that the differences in corneal parameters remained significant in patients who had had diabetes for ≥10 years. In participants with disease <10 years, only CV and CCT were significantly different between groups.

Similarly, ECD, CV, and CCT differed between diabetics with high glycated haemoglobin (≥7 percent) vs controls. In patients with levels <7 percent, only CV and CCT diverged significantly from control values.

The researchers also saw that older age emerged as an important factor. In patients with disease duration ≥10 years, ECD and CV were significantly different between groups in those aged ≥60 years, while CCT showed the same effect in the ≥50-year age group. Hexagonality was only different between patients and controls in participants aged 60–69 years.

“[T]he corneas of patients with T2D showed an increase in thickness and CV and reductions in ECD and hexagonality compared with the healthy controls,” the researchers said. “Therefore, it is necessary to evaluate not only the retina but also the corneal endothelial cells regularly during follow-up for T2D patients.”