Aim – to evaluate ocular surface changes in patients with primary open-angle glaucoma (POAG) as well as the hypotensive effect of preservative-free betaxolol eye drops. Material and methods. A total of 22 patients (42 eyes) aged 55-83 with POAG stage I-II were examined. All of them were switched from betaxolol b.i.d. to its preservative-free analogue (Xonef BK). The baseline examination included visual acuity measurement, Morisky-Green test (questionnaire), Norn test, Schirmer’s test, lissamine green staining, and ocular tonometry. The latter was repeated 2 and 4 weeks after the drug had been switched, while the whole complex - 2 months after the beginning of the study. Results. The total tear production in POAG patients under betaxolol therapy was 19.1±10.6 mm. After the 2 months of preservative-free betaxolol use there were no statistically significant changes in Schirmer’s test results (p=0.248). Tear film break-up time (Norn test) improved from 7.8±0.5 sec to 9.8±0.8 sec (p=0.067) as well as the results of lissamine green staining (W=90.0, p<0.022). In the Morisky-Green Test betaxolol patients scored only 2.6±0.05 points on average, thus showing non-compliance. After the 2 months of preservative-free betaxolol instillations the scores increased up to 3.1±0.07 (p=0.04). According to Dunnett’s test, used for multiple comparisons, intraocular pressure did not change significantly in either of the study periods (baseline and follow-up measurements at weeks 2, 4, and 8 were taken into account). Conclusion. The study proves Xonef BK safe, effective, and appropriate in all types of glaucoma.