Tear function and ocular surface changes in noninsulin-dependent diabetes mellitus

Purpose: To describe the ocular surface disorder in patients with diabetes. Design: A prospective, case-controlled study. Participants: Eighty-eight eyes of 50 noninsulin-dependent diabetes mellitus patients seen at the Department of Ophthalmology, Kobe University School of Medicine, from September 1998 through February 1999, and 40 eyes of 20 healthy control individuals were studied, Intervention: All subjects underwent routine ophthalmic examinations, corneal sensitivity measurements, Schirmer test, tear film break-up time (BUT) analysis, and conjunctival impression cytologic analysis. Main Outcome Measures: Patients and control subjects were compared for corneal sensitivity, tear function parameters, goblet cell density, and squamous metaplasia grade. The relation of diabetic peripheral neuropathy, metabolic control, duration of disease, and status of retinopathy to the ocular surface disorder was also noted. Results: The mean corneal sensitivity was significantly lower in diabetic patients, diabetic patients with peripheral neuropathy, and poorly controlled diabetes compared with control subjects (P < 0.001). The BUT and Schirmer test values were also significantly lower in the diabetic group, in patients with peripheral neuropathy and poor metabolic control. Impression cytologic analysis showed goblet cell loss and conjunctival squamous metaplasia, both of which again related to peripheral neuropathy, poor diabetic control, and decreased corneal sensitivity. The examined parameters did not relate to duration of disease or status of diabetic retinopathy. Conclusions: The ocular surface disease in diabetes is characterized by a disorder of tear quantity and quality, squamous metaplasia, and goblet cell loss, all of which seem to evolve in close proximity to the status of metabolic control and peripheral neuropathy.