Objective:To assess the status quo of uncertainty in illness among patients undergoing daytime ophthalmic surgeries and to identify its influencing factors.Methods:Patients who underwent surgery in the Ophthalmic Daytime Surgery Wards of Beijing Tongren Hospital, Capital Medical University, from January to June 2023, were selected by convenience sampling. Data were collected using a general demographic survey and the Medical Uncertainty Inventory Scale (MUIS/MUIS-A). Multiple linear regression analysis was employed to investigate the factors influencing the uncertainty in illness among these patients.Results:Out of 248 questionnaires distributed, 243 were effectively collected, resulting in a 97.98% response rate. The scores on the MUIS/MUIS-A ranged from 55 to 144, with a median of 102. Multiple linear regression analysis indicated that acceptance of the disease, educational level, and the number of surgeries were significant factors influencing the uncertainty in illness among these patients ( P<0.05) . Conclusions:The uncertainty in illness among patients undergoing daytime ophthalmic surgery is above the medium level. Factors such as acceptance of the disease, educational level, and the number of surgeries significantly influence this uncertainty.