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Addition of dorzolamide to timolol in primary open-angle glaucoma shows augmented reduction of intraocular pressure. It is unknown as yet if addition of dorzolamide will alter hemodynamics.Fifteen patients with primary open-angle glaucoma were placed on a medication-dependent 1-week to 4-week washout that included maintenance on timolol. After washout, baseline measurements were taken (timolol). They were studied after a month on timolol or dorzolamide-timolol (Cosopt; Merck, Inc, Whitehouse Station, New Jersey), with the second drug preceded by another month of timolol maintenance and second baseline measurements. At each visit, visual function, intraocular pressure, and ocular hemodynamics were monitored, including indocyanine green and fluorescein angiography and color Doppler imaging.Cosopt significantly reduced intraocular pressure (14.7 to 13.4 mm Hg, P.05) and increased arteriovenous passage time (superior temporal artery) of fluorescein dye (2.13 to 1.76 seconds, P =.01) but had no effect on visual function.When compared with timolol in primary open-angle glaucoma, Cosopt augments ocular tension reduction and reduces the amount of time required for blood to pass through the superior retinal vasculature.

Purpose: Scanning laser ophthalmoscopy is capable of producing high-resolution fluorescein angiograms. Measurements of capillary blood velocities in the fovea are well established. In this study, we used an identical technique to measure particle velocities in the superficial layers of the optic nerve head. We compared these data with simultaneous velocity measurements in the retinal and macular vasculature. Methods: Fluorescein angiograms were performed in 30 subjects (12 men, 18 women; mean age, 26 years; standard deviation [SD], 3 years). Off-line, the velocities of hypofluorescent particles through the microvasculature of epipapillary and macular vessels were measured by image-processing techniques. We also assessed the arteriovenous passage (AVP) time of the fluorescein dye front. Results: Epipapillary blood velocities ranged from 2.7 to 6.5 mm/sec (mean, 4.0 mm/sec; SD, 0.99 mm/sec) and differed significantly from macular capillary blood velocities (MCBVs), which ranged from 1.67 to 3.31 mm/sec (mean, 2.53 mm/sec; SD, 0.34 mm/sec). The AVP time in all subjects was 1.74 ± 0.5 sec (mean ± SD) and correlated with the MCBV (P Conclusions: The scanning laser methodology, adapted to objectively assess velocities in the epipapillary vasculature, shows that these measurements are neither correlated with velocities in the perifoveal network, nor inversely correlated with overall retinal transit time. Epipapillary blood velocities were found to be substantially higher than those measured in macular capillaries. This result might be explained by the different anatomy of epipapillary vessels compared with macular capillaries.

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 ( r = .57; P = .02) and end-diastolic velocity ( r = .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.

Purpose β-Adrenergic blocking drugs lower intraocular pressure. The question of whether these drugs also alter, either directly or indirectly, orbital hemodynamics is potentially of great importance for patients with normal-tension glaucoma who may have some degree of reversible vasospasm. Methods We compared the effect of selective (betaxolol) and nonselective (timolol) β-adrenergic blocking drugs on flow velocities (as determined by color Doppler imaging) in orbital vessels in 13 patients with normal-tension glaucoma (mean age, 62 ± 3 years; mean intraocular pressure, 15 ± 2 mm Hg). A one-month drug treatment double-masked crossover design, with a three-week washout before each drug, was used. Results Neither drug changed peak systolic velocity in any of the four vessels studied (ophthalmic, nasal and temporal posterior ciliary, and central retinal arteries). Additionally, timolol did not alter end-diastolic velocity or resistance index (defined as [peak systolic velocity minus end-diastolic velocity] divided by peak systolic velocity) in any of the vessels measured. In contrast, betaxolol tended to increase end-diastolic velocity and to decrease resistance index: the four-vessel average end-diastolic velocity increased 30% (P = .08), and the four-vessel average resistance index decreased significantly (P = .04). These reductions in resistance index occurred despite that betaxolol, in contrast to timolol, did not significantly decrease intraocular pressure. Conclusions These results suggest that, in patients with normal-tension glaucoma, selective β-adrenergic blockade (betaxolol) may have ocular vasorelaxant effects independent of any influence on intraocular pressure, whereas nonselective blockade (timolol) lowers intraocular pressure without apparently altering orbital hemodynamics.

A total synthesis of the novel antifungal substance myxothiazol 1 isolated from the myxobacterium Myxococcus fulvus is described. The synthesis is based on elaboration of the S-E,E -diene thioamide 1 5 and the 2 R S , 3 S R amide aldehyde 2 5 as key intermediates, followed by conversion of 1 5 into the bis -thiazole 1 9 and a final Wittig coupling reaction between 2 5 and the salt 2 0 c leading to 7 S ,18 S R , 19 R S myxothiazol.