Abstract:AIM: To explore whether unilateral herpes simplex keratitis (HSK) can cause morphological changes of bilateral meibomian glands (MGs) based on artificial intelligence (AI) analytical system. METHODS: In the retrospective study, 29 patients with unilateral HSK and 29 participants matched in terms of age and sex were included as control group. Meibographic images of the upper eyelid using Keratograph 5M and assessed ocular surface parameters including tear meniscus height and tear break-up time. MG density and vagueness values were automatically analyzed and calculated using an AI analytical system. We compared the differences between the affected and the contralateral unaffected eyes in HSK patients, and the normal control eyes. We employed either the paired t-test or the Wilcoxon signed-rank test to compare significant difference between the affected and unaffected eyes in HSK patients or between the HSK group and control group. RESULTS: The MG density was 0.19±0.09 in the HSK-affected eye and 0.18±0.07 in contralateral unaffected eye, which had no significant difference (P=0.616). The MG density between the affected eye with HSK and the normal control group was statistically significant (P=0.028). There was a significant difference in MG density between the contralateral unaffected eye and the normal control group (P=0.012). However, no significant difference in vagueness value was observed between the eye with HSK and the control group or between HSK eye and contralateral eye. CONCLUSION: The MG density between the HSK-affected eye and the contralateral unaffected eye don’t significantly differ, whereas there is a significant decrease in the HSK group compared to that of the normal participants. Unilateral HSV keratitis may suffer from bilateral changes of MG morphology indicating bilateral dry eye. Therefore, the fellow eye of patients with unilateral HSK should be considered a potential case of MG dysfunction, necessitating early treatment for bilateral dry eye in the clinic.