Abstract: Objective To observe the meibomian gland-related indexes in patients with type 2 diabetes mellitus (T2DM) and to explore the influencing factors of abnormal structure and function of meibomian gland. 
Methods In total, 130 patients (130 eyes) with T2DM were selected as experimental group and 46 healthy persons (46 eyes) were selected as control group. All subjects underwent the standard patient evaluation of eye dryness scoring (SPEED), Lipiview examination and meibomian gland evaluator (MGE). The patients were divided into different groups according to duration of T2DM, glycosylated hemoglobin level (HbA1c) and blood lipids level and presence of abnormal lipoprotein metabolism. Lipid layer thickness (LLT), tear break up time (TBUT) and tear secretion function ［Schirmer Ⅰ test (SIt)］, percentage of partial glands (MGP), meibomian gland yielding liquid secretion (MGYLS), meibomian gland yielding secretion score(MGYSS) were analyzed.  
Results HbA1c, SPEED and MGP in diabetes group were higher than those in control group, while LLT, BUT, SIt, MGYLS and MGYSS were lower than those in control group (P＜0.05). There was no statistically significant difference in gender, age, HbA1c, SPEED score, LLT, BUT, and SIt between the group with a disease course of ＜10 years and the group with a disease course of ≥ 10 years (P＞0.05). MGP in the group with a disease course of ≥10 years was higher than that in the group with a disease course of ＜10 years, while MGYLS and MGYSS were lower than those in the group with a disease course of ＜10 years (P＜0.05). There was no statistically significant difference in gender, age, and SPEED scores between the HbA1c＜7% group and the HbA1c≥7% group (P＞0.05). The LLT, BUT, SIt, MGYLS, and MGYSS of the HbA1c≥7% group were lower than those of the HbA1c＜7% group, and MGP was higher than those of the HbA1c＜7% group (P＜0.05). There was no significant difference in gender, age, and SPEED scores between the abnormal lipid metabolism group and the normal lipid metabolism group (P＞0.05). The LLT, BUT, SIt, MGYLS, and MGYSS in the abnormal lipid metabolism group were lower than those in the normal lipid metabolism group, while MGP was higher than those in the normal lipid group (P＜0.05). In the meibomian gland of T2DM patients, the meibomian gland were shortened, thickened, distorted, and some glands were missing and sparsely arranged. The meibomian glands in the normal control group are densely distributed, with glandular lengths approaching the upper end of the meibomian plate. 
Conclusion The structure and function of meibomian gland are abnormal in T2DM patients, and the quality of tear film is decreased, which result in ocular surface discomfort in all groups, and the ocular surface discomfort and meibomian gland abnormality are more serious in patients with poor control of blood sugar and longer course of disease. Diabetic patients with abnormal lipoprotein metabolism have worse tear film quality and meibomian gland function. 

Key words: diabetes mellitus, type 2, meibomian glands, lipid layer thickness