Study suggests positive relationship between diabetes and keratoconus

This retrospective study found that there may be a positive association between type 2 diabetes and the presence and severity of keratoconus.

These results are interesting as this is first time a study has demonstrated a higher prevalence of type two diabetes in keratoconus patients and a positive association between type two diabetes and the severity of keratoconus. Previous studies have found either no difference in the prevalence of diabetes or a lower incidence of diabetes in keratoconus patients compared to patients without keratoconus. It has been suggested in the past that diabetes may actually have a protective effect on keratoconus due to the increased collagen crosslinking from glycosylation in diabetics.

The authors compared the prevalence of diabetes in 1,377 keratoconus patients seen at Wills Eye Hospital Cornea Service in Philadelphia from January 2008 to August 2012 to 4,131 patients without keratoconus referred to the cornea service. They also compared the severity of keratoconus in 75 keratoconus patients with type 2 diabetes and 225 keratoconus patients without diabetes.

They found that the prevalence of type 1 diabetes was similar between keratoconus patients and controls. However, the prevalence of type 2 diabetes was higher in keratoconus patients (6.75% vs. 4.84%, P = 0.005). Also, the risk of having more severe keratoconus was higher in patients with diabetes than without (P = 0.006; odds ratio 2.691).

Further prospective study is certainly necessary to evaluate this association between diabetes and keratoconus. However, the findings of this study may call into question previous hypotheses regarding the protective effect of diabetes on keratoconus.