To compare the protective effect of corneal protectant hydroxypropyl methylcellulose (HPMC) and balanced salt solution (BSS) on corneal epithelium in vitreous body surgery for proliferative diabetic retinopathy (PDR).

A randomized controlled clinical trial was conducted.Fifty eyes of 50 patients with PDR who underwent minimally invasive vitrectomy in Xuzhou First People's Hospital from September 2018 to January 2019 were enrolled and randomly divided into HPMC group and BSS group, with 25 eyes in each group.All eyes underwent three-channel minimally invasive vitrectomy under non-contact wide-angle lens, and 2% HPMC and BSS were applied to keep the ocular surface moist according to grouping during the operation.The combination of cataract surgery, operation time, application times of 2% HPMC or BSS and the grade of corneal epithelial edema before and after operation were recorded.The patients were followed up for 1 month.Corneal fluorescein sodium staining and tear film break-up time (BUT) test were performed before operation and at 1 day, 3 days, 10 days and 1 month after operation.Schirmer Ⅰ test (SⅠt) and ocular surface disease index (OSDI) questionnaire were carried out before operation and at 1 month after operation.The study protocol adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Xuzhou First People's Hospital (No.xyyⅡ[2018]005). Written informed consent was obtained from each patient prior to any medical examination.

The average frequency of application of eye drops in the HPMC group was (5.00±1.56) times, which was significantly less than (50.56±17.00) times in the BSS group (t=-13.071, P<0.01). The postoperative corneal edema score of the HPMC group was 1.0 (1.0, 1.0) point, which was lower than 2.0 (2.0, 2.0) points of BSS group, and the difference was statistically significant (Z=-4.909, P<0.01). There were statistically significant differences in postoperative corneal fluorescein sodium scores among 1 day, 3 days, 10 days and 1 month in the two groups (HPMC group: χ²=36.040, P<0.01; BSS group: χ²=50.892, P<0.01). The 1-, 3- and 10-day postoperative corneal fluorescein sodium scores in the HPMC group were significantly lower than those in the BSS group (all at P<0.05). One-day, 3-day, 10-day and 1-month postoperative BUT values were (6.15±2.20), (6.95±2.46), (6.16±2.11) and (5.81±2.92) seconds in the HPMC group, respectively, and were (3.89±1.87), (5.32±2.59), (5.01±2.12) and (4.97±2.10) seconds in the BSS group, respectively.There were significant differences in BUT between the two groups at different time points (F_group=5.240, P<0.05; F_time=2.846, P<0.05). The preoperative and 1-month postoperative SⅠt values in the BSS group were (12.24±5.55)mm and (9.96±4.53)mm, respectively, showing a statistically significant difference (t=3.863, P=0.001). The postoperative OSDI score in the BSS group was (51.00±12.04) points, which was significantly higherly than the preoperative value of (47.89±10.95) points, and the difference was statistically significant (t=-2.111, P<0.05).

Compared with BSS, 2% HPMC in minimally invasive vitreous surgery has better protective effect on corneal epithelium of PDR, reduces the frequency of eye drop use during the surgery and shortens the repair time of ocular surface tissue after surgery.

Diabetic retinopathy, proliferative; Vitrectomy, minimally invasive; Corneal protectant; Ocular surface repair; Hydroxypropyl methyl cellulose