The ocular adverse effects of diabetes aren’t limited to risk of diabetic retinopathy. These patients are at inherent risk of complications when wearing contact lenses, according to a report published in the Journal of Diabetes and Its Complications. The Texas-based research team looked into research, dating as far back as four decades, that connects damage to the corneal epithelium in diabetes patients with contact lens use. Their study suggests optometrists must carefully consider the duration of disease, the level of glycemic control, the presence of retinopathy and the diabetic patient’s overall health before fitting contact lenses.

Primarily, the authors note, the disease takes a toll on the corneal epithelium. It can change the composition of the basement membrane, lead to abnormal epithelial cell adhesion, disrupt of the epithelial barrier and cause persistent epithelial defects and corneal neuropathy. Rabbit and other animal model studies suggest that extended contact lens wear can throw fuel on that fire, for instance by thinning the corneal epithelium. In some of the research, investigators say, the cornea thins in diabetes patients even without contact lens wear. 

In addition to mechanical damage, contact lenses can increase risk for diabetes patients by exposing them to more impactful infections from bacteria, fungus and yeast, according to the study. Researchers chalk this up to the patient’s altered immunity and contact lens’s association with pathogens, which are often heightened due to poor hygienic care. Even devices such as tear glucose monitoring lenses can heighten infection risks, the authors say.

Ultimately, the team says, their research is based on only a handful of studies, and more large-scale prospective studies are necessary to evaluate the pathobiology of the diabetic corneal epithelium under contact lenses to establish an accurate safety assessment.