Corneal and Tear Film Changes in Chinese Patients With Type 2 Diabetes

Corneal and Tear Film Changes in Chinese Patients With Type 2 Diabetes: a Cross-sectional Controlled Study

Diabetes mellitus has been associated with ocular surface damage and exacerbates dry eye disease (DED) pathology. To investigate clinical and inflammatory changes in the ocular surface of insulin-independent type II diabetic patients. This cross-sectional control study will recruit 200 Type 2 diabetic patients and 200 age- and sex-matched subjects without DM.

Diabetes mellitus (DM) is a developing global health challenge due to the multiple complications associated with long-term hyperglycemia. Although diabetic retinopathy is the most prevalent and well-known ophthalmic consequence, diabetes also causes clinically significant effects on the ocular surface. Among the ocular surface diseases, dry eye disease (DED) is the most common. Multiple mechanisms, such as ocular surface and lacrimal gland inflammation, neurotrophic deficiency, and meibomian gland dysfunction (MGD), play significant roles.

A loss of tear film homeostasis characterizes DED. DM is one of the risk factors for DED; 47% of DM patients suffer from ocular surface damage due to negative alterations to the tear film, corneal thickness, corneal epithelium, corneal nerve, and corneal endothelium. It has been suggested that one or more of the following initial events may lead to alterations described in the tear film and ocular surface of patients with DM: a) chronic hyperglycemia, b) corneal nerve damage, and c) impairment on insulin action.

Previous studies have explored the association between DM and ocular surface dysfunction. However, ocular surface and tear film parameters in diabetic patients are lacking in the Chinese population. Moreover, corneal nerve damage and ocular surface inflammation have not been systematically evaluated. Our study aimed to investigate clinical and inflammatory changes in the ocular surface of insulin-independent type II diabetic patients in a Chinese population.

Inclusion Criteria:

• Participants are diagnosed with dry eye according to the TFOS DEWS II diagnostic criteria: (a) OSDI questionnaire ≥13, (b) Non-invasive tear breakup time (NITBUT) <10 s, (c) ocular surface staining >5 corneal spots, greater than nine conjunctival spots (The presence of two or more criteria was used to establish a positive DE diagnosis).
• Age ≥ 18

Exclusion Criteria:

• Active ocular infection, such as infectious, viral, chlamydial, or immunologic conjunctivitis
• A history of ocular surgery that might affect the corneal or tear film, such as corneal refractive surgery, keratoplasty, cataract surgery, or ocular laser surgery
• Long-term contact lens wear
• Other ocular diseases being treated might affect the corneal or tear film: such as glaucoma, dacryocystitis, uveitis, and pterygium.