Purpose Drugs increasing perfusion to the optic nerve head have potential to improve prognosis of primary open angle glaucoma (POAG). The influence of 2 topical antiglaucomatous agents on choroidal (ocular pulse amplitude, OPA), short posterior cilary artery (SPCA) and central retinal artery (CRA) vascular systems was evaluated in POAG patients. Methods The effect of timolol and dorzolamide (BID, 1 eye) on OPA (OBF Labs), SPCA and CRA hemodynamics (Elegra Advanced System), IOP, and systemic perfusion parameters was investigated in 14 POAG patients. Measurements were taken before, 4 weeks after application of timolol alone, and following another 4 weeks of combined therapy. Results Following application of timolol in drug treated POAG eyes IOP (mmHg) was significantly (sig., p< 0.0001) reduced and was further sig. (p< 0.0005) reduced by combined therapy. When compared to pretreatment values OPA and SPCA perfusion parameters were not sig. (p> 0.05) altered following application of timolol, whereas dorzolamide sig. (p< 0.001) increased OPA, peak systolic and enddiastolic velocities and sig. (p< 0.002) decreased resistance and pulsatility indexes. CRA vasculature showed similar perfusion profiles. Systemic perfusion parameters were not sig. (p> 0.05) altered. Conclusion Combined timolol and dorzolamide therapy reduced IOP by 36.1%, which may help to reach individual target IOP. Dorzolamide improved hemodynamics in the vascular systems that specifically supply the optic nerve head, which may improve prognosis in this group of multifactorial diseases.