Patients with diabetes often have eye-related complications such as retinopathy and glaucoma, but dry eye disease may also be present, further affecting vision. A recent study investigated the clinical and inflammatory changes in the ocular surface that those with insulin-dependent type 1 diabetes may experience.1

The observational study included 209 eyes of 106 patients with Type 1 diabetes. The researchers performed ocular surface clinical assessments and tested corneal sensitivity and tear film stability to evaluate the function of the ocular surface system. Each patient also completed an Ocular Surface Disease Index (OSDI) questionnaire. To detect neuromediators and inflammatory molecules, the researchers collected conjunctival impression cytology specimens.

They found that patients with more chronic disease, higher HbA1c levels and proliferative diabetic retinopathy exhibited reduced corneal sensitivity. Similarly, reduced tear break-up time was observed in those with long-standing diabetes or more severe retinopathy. The OSDI questionnaire scores showed a direct correlation with increased HbA1c levels.

Compared with healthy controls, patients with Type 1 diabetes showed significant increases in neuropeptide Y, STAT-5 and ICAM-1. The researchers also found a direct correlation between NPY concentration and ICAM-1 values in patients with Type 1 diabetes, both of which contribute to the immune response of the ocular surface.2-3

The researchers ultimately found that patients with long-standing Type 1 diabetes had chronic ocular surface inflammation due to neurogenic dysregulation of para-inflammatory homeostatic mechanisms. These patients reported ocular discomfort but had only a modest reduction of corneal sensitivity and no signs of neurotrophic keratopathy.

The researchers noted that disease duration, increased HbA1c levels and severe diabetic retinopathy seem to be the most critical factors.

1. Di Zazzo A, Coassin M, Micera A, et al. Ocular surface diabetic disease: A neurogenic condition? The Ocular Surface. October 1, 2020. [Epub ahead of print].

2. Sabatino F, Di Zazzo A, De Simone L, et al. The intriguing role of neuropeptides at the ocular surface. The Ocular Surface 2017;15:1:2-14.

3. Pflugfelder SC, Stern M, Zhang S, et al. LFA-1/ICAM-1 interactions as a therapeutic target in dry eye disease. J Ocul Pharmacol Ther 2017;33:1:5-12.