Long-term poor glycemic control in patients with diabetes may be associated with corneal morphological and functional changes, which researchers in India believe can be detrimental to the ultimate health of cornea over the long-term. The team noted that increasing severity of diabetic retinopathy (DR) is associated with corneal endothelial changes.

In 592 diabetic patients and 596 controls, the study analyzed the corneal endothelium, recording specular microscopy measurements of central corneal thickness (CCT), endothelial cell density (ECD), variation in cell size (CV) and hexagonality . The researchers also analyzed the influence of DR severity, duration of diabetes and level of glycosylated hemoglobin (HbAlc).

In diabetic patients, the study noted significantly reduced cell density and hexagonality and higher CV and CCT. Comparing the diabetic patients with controls, the researchers found significant differences in CCT (522µm vs. 515µm in controls), ECD (2485cells/mm2 vs. 2556cells/mm2), CV (40.3 vs. 37.2) and hexagonality (39.9 vs. 44.6). They also noted that longer duration of diabetes (>10 years) and poor glycemic control (HbAlc > 7.5%) were associated with similar results. Multivariate analysis showed that increasing age was significantly associated with lower ECD, hexagonality and CCT and also higher CV.

The researchers noted that their study established for the first time that, as the DR grade worsens, the CCT and the CV increase, whereas the cell density and hexagonality decrease significantly, the researchers noted. “The presence of DR and its severity may warrant a thorough preoperative corneal assessment, especially in populations who receive a large number of cataract surgeries every year.”

Jha A, Verma A, Alagorie AR. Association of severity of diabetic retinopathy with corneal endothelial and thickness changes in patients with diabetes mellitus. Eye (Lond). June 11, 2021. [Epub ahead of print].