Purpose: To identify factors influencing vision-related quality of life (VRQOL) according to glaucoma severity. Methods: A total of 901 patients with varying stages of glaucoma were recruited from the prospectively designed LIGHT (Life Quality of Glaucoma Patients Who Underwent Treatment) study organized by the Korean Glaucoma Society. Participants completed a basic questionnaire collecting socioeconomic status and clinical information, in addition to the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). Subjects were classified by mean deviation (MD) of integrated binocular visual field (IVF) into mild, moderate and severe damage groups. Factors were evaluated for their influence on VRQOL according to glaucoma severity using univariate and multivariable regression models between Rasch-analysed NEI VFQ-25 subscale scores and different variables. Results: The mild, moderate and severe groups contained 720, 111 and 70 patients, respectively; the mean IVF MD in each group was À1.4, À8.5 and À17.9 dB. Significant differences were observed among the three groups with respect to age, IVF MD, visual acuity (VA), education level, income level, number of glaucoma medications prescribed and follow-up period. The most influential factor associated with VRQOL according to glaucoma severity was VA. The VA of the better eye was much more influential on VRQOL than the VA of the worse eye in the moderate and severe defect groups, and the impact of VA on VRQOL was more prominent in advanced glaucoma. Conclusion: Visual acuity is the most influential factor on VRQOL in patients with glaucoma. Preservation of VA should be strongly prioritized to maintain good VRQOL.