Objective: To evaluate the clinical effect of diclofenac sodium combined with vitamin C to relieve  discomfort after transepithelial photorefractive keratometry (TPRK). Methods: In this randomized control  trial, seventy patients undergoing TPRK surgery were recruited from February to June 2018 and divided  into observation group and control group, with 35 patients in each group. The observation group was  treated with diclofenac sodium eyedrops combined with oral vitamin C, and the control group was treated  only with diclofenac sodium eye drops. Symptoms and signs were observed on day 1, day 3 and day 4  after surgery, and eye irritation symptoms were evaluated by a questionnaire, including pain, foreign body feelings, tearing, photophobia, and discomfort in blinking. The results were analyzed with an unpaired t test  and repeated measures ANOVA. Results: There were statistically significant differences between the two  groups (pain score: F=10.219, P=0.002; foreign body feelings score: F=8.637, P=0.005; tearing: F=5.108,  P=0.027. Repeated measures ANOVA). There were statistically significant differences for the above  scores between the two groups on day 0 and day 1 after surgery (all P<0.05), but no statistically significant  differences on day 2. The differences between the two groups were not statistically significant (photophobia  score: F=3.626, P=0.061; discomfort score in blinking: F=2.778, P=0.100). But there were statistically  significant differences between the two groups in the total discomfort score (F=7.785, P=0.001).  Conclusion: Diclofenac sodium combined with vitamin C can relieve pain after TPRK surgery and reduce  discomfort in patients.