[Tear film function of patients with type 2 diabetes].

Objective: To study the tear film function of patients with type 2 diabetes and to investigate the risk factors of dry eye in these patients.

Methods: Totally 111 patients with type 2 diabetes and 100 age- and sex-matched control subjects were studied. Tear film function was evaluated by dry eye syndrome, tear breaking up time (BUT), corneal fluorescein staining, Schirmer I test (SIt), and tear film lipid layer observation with tear scope. Dye eye score was calculated with the results of these tests.

Results: When compared with the controls, patients with type 2 diabetes showed higher dry eye score (diabetics 3.28 +/- 1.56, control 2.31 +/- 1.50, P < 0.01) and faster BUT [diabetics (6.50 +/- 4.84) s, control (12.26 +/- 7.16) s, P < 0.01], but similar SIt [diabetics (10.61 +/- 6.86) s, control (10.92 +/- 7.05) s, P > 0.05]. More diabetic patients were diagnosed as dry eye(diabetics 19.8%, control 8.0%, P < 0.05). According to their retinopathy, the diabetic patients were divided into three groups: without diabetic retinopathy (DR), with background DR, and with proliferative DR. For these three groups, the dry eye scores were 2.95 +/- 1.50, 3.38 +/- 1.48 and 4.11 +/- 1.60, respectively (P < 0.01); the SIt were (10.95 +/- 6.89) mm, (11.71 +/- 7.30) mm and (7.63 +/- 5.20) mm, respectively (P > 0.05); the BUT were (7.53 +/- 5.23) s, (5.88 +/- 4.10) s and (4.47 +/- 4.17) s (P < 0.05). Patients with DR were then devided into two groups: with photocoagulation and without photocoagulation. For these two groups, the dry eye scores were 4.71 +/- 1.14 and 3.26 +/- 1.15, respectively (P < 0.01); the BUT were (2.93 +/- 2.06) s and (6.26 +/- 4.36) s, respectively (P < 0.01); the SIt were (7.21 +/- 6.51) mm and (11.33 +/- 6.73) mm, respectively (P < 0.05); the rates of corneal fluorescein staining were 50.0% and 17.9%, respectively (P < 0.05). Dry eye score had a good correlation with diabetic retinopathy and photocoagulation (P < 0.01), but was poorly correlaed with age, gender, insulin, duration of diabetes mellitus, and metabolic control (P > 0.05).

Conclusions: Patients with type 2 diabetes tend to develop tear film dysfunction. The disorders of tear film quantity and quality seem relevant to the stage of diabetic retinopathy and photocoagulation.