Aim: To evaluate changes in the subjective perception of visual acuity in everyday life during intravitreal ranibizumab treatment in patients with diabetic macular edema using the Slovak version of the international NEI VFQ-25 questionnaire. Material and Methods: In a prospective study, 48 eyes of 30 treatment-naive patients were evaluated, and met the indication criteria. We determined best-corrected visual acuity in letter score (LS), intraocular pressure (IOP), central retinal thickness (CRT) and total macular volume (TMV). Patients received the NEI VFQ-25 questionnaire before the first and then after three, six and twelve months of treatment. Results: Before treatment, LS averaged 68.1 letters, IOP 17.6 mmHg, CRT 480.5 μm, and TMV 11.2 mm3. After twelve months of intravitreal treatment, LS averaged 72.6 letters, IOP 17.0 mmHg, CRT 332.4 μm, and TMV 9.3 mm3.Comparison of data relating to subjective perception of vision before and after twelve months of treatment: perception of general health improved by 7%, vision in general improved by 15%, eye pain decreased by 8%, near vision improved by 12%, distance activities improved by 5%, social functioning improved by 4%, mental health improved by 6%, difficulties with functioning improved by 16%, dependency improved by 1%, driving improved by 2%, color vision improved by 7%, and peripheral vision improved by 9%. Conclusion: We determined that anti-VEGF ranibizumab treatment improved objective parameters after one year of intravitreal therapy in LS, CRT and TMV. Subjective changes in visual perception improved in all the monitored parameters after one year of treatment.