Hemodynamic and visual function effects of oral nifedipine in patients with normal-tension glaucoma

PURPOSE: To investigate ocular hemodynamic and visual function changes in patients with normal-tension glaucoma after treatment with a calcium channel blocker (nifedipine). METHODS: In 21 patients with normal-tension glaucoma, color Doppler imaging of the ophthalmic, central retinal, and short posterior ciliary arteries was carried out after a 4-week washout of prior drug treatment and again after 6 months of treatment with nifedipine (30 mg per day). Visual field sensitivity, spatial contrast sensitivity, and intraocular pressure were also recorded. RESULTS: Three subjects experienced intolerable side effects from the drug and were removed from the study. In two other patients, visual function was substantially reduced after 4 months of treatment; nifedipine was discontinued. In the remaining 16 subjects, mean intraocular pressure, retrobulbar hemodynamics, visual field mean sensitivity, and contrast sensitivity at 3, 12, and 18 cycles per degree (cpd), respectively, were unchanged after nifedipine treatment. Contrast sensitivity at 6 cpd, however, improved after drug treatment (P = .004). Individuals with the greatest improvements in contrast sensitivity at 6 cpd showed the largest increases in ophthalmic arterial peak systolic velocity (Υ = .57; P = .02) and end-diastolic velocity (Υ = .65; P = .001). CONCLUSION: Nifedipine fails to provide uniform visual function or retrobulbar hemodynamic responses in patients with normal-tension glaucoma. Those patients who do show improved visual function also show improved indices of retrobulbar perfusion.