Effects of Long-Term Hypotensive Therapy with Nonselective Beta-Blockers on Ocular Hemodynamics in Primary Open-Angle Glaucoma

Purpose: Vascular factors have been implicated in the progression of glaucoma, but the impact of long-term beta blocker therapy on ocular circulation remains largely undefined. The purpose of this study was to prospectively evaluate the level of retrobulbar blood flow in patients with primary open-angle glaucoma (POAG) before and during long-term treatment with a nonselective topical beta blocker, and to compare these measures with those in untreated control subjects. Methods: Twelve control subjects and 12 patients with POAG were tested for intraocular pressure (IOP), heart rate, blood pressure, contrast sensitivity, visual field sensitivity, and retrobulbar flow velocity as measured by color Doppler imaging (CDI). Patients were evaluated after 4 weeks of drug washout and again after 3 and 6 months of treatment with a nonselective beta blocking agent. Control subjects were tested once. Results: At baseline, patients with POAG had significantly higher IOP than normal controls; CDI measures of the central retinal artery (CRA) and short posterior ciliary artery (SPCA) in the patients were significantly different from those in control subjects. In the patients, treatment resulted in a significant reduction in IOP and in CRA and SPCA resistance index. Conclusion: Untreated patients with POAG have altered circulation in the CRA and SPCA compared with subjects of similar age and gender. These measures recover significantly during topical beta blocker therapy. The relationship of the pretreatment deficit and posttreatment recovery of CDI blood flow measures to the progression and therapeutic impediment of glaucomatous optic nerve deterioration remains to be determined.