AIM: To investigate effects of different corneal protective agents on ocular surface in vitrectomy in patients with diabetes.METHODS: Totally 90 patients(90 eyes)with diabetes who received vitrectomy were randomly divided into HPMC group(30 eyes), SHSCS group(30 eyes)and BSS group(30 eyes). Hydroxypropyl methyl cellulose(HPMC)and sodium hyaluronate sodium chondroitin sulfate(SHSCS)were used to cover the corneal surface to avoid the cornea drying in HPMC group and SHSCS group, respectively. Balanced salt solution(BSS)was continuously dripped on the cornea to keep the cornea moist in BSS group. Schirmer Ⅰ test(SⅠt), breaking up time(BUT)and central corneal thickness were performed before and after operation. Their changes were observed and compared.RESULTS: At 1wk and 1mo after operation, compared with HPMC group and SHSCS group, SⅠt was significantly increased and BUT was significantly shortened in BSS group(P<0.05). At 1wk after operation, BUT of HPMC group was significantly shortened compared with SHSCS group(P<0.05). At 3mo after operation: SⅠt and BUT of the three groups were no significant difference compared with before operation(P>0.05). At 1d after operation, the corneal thickness of BSS group was significantly increased compared with HPMC group and SHSCS group(P<0.05). At 1wk after operation, the corneal thickness of the three groups were no significant difference compared with before operation(P>0.05).CONCLUSION:The patients with diabetes use HPMC and SHSCS can protect the cornea and maintain the stability of tear film in vitrectomy. Different corneal protectors can be selected according to the clinical practice.