Comparative analysis of the effects of dorzolamide and latanoprost on ocular hemodynamics in normal tension glaucoma patients

PURPOSE. To compare the effects of latanoprost (Xalatan®) and dorzolamide (Trusopt®) on ocular hemodynamics in normal-tension glaucoma patients. METHODS. A randomized, single-masked, parallel design study was conducted. After a 4 - week washout period, 20 normal tension glaucoma patients, recruited from a single university-based ophthalmology clinic, received either latanoprost once daily or dorzolamide 3 times daily for 4 weeks. The subjects were examined at baseline and post-treatment. Outcome measures included heart rate (HR), blood pressure (BP), logMar visual acuity (Vii)(VA), contrast sensitivity (CS), intraocular pressure (lOP)(IOP), color Doppler imaging (CDI), and fluorescein angiography with the Rodenstock scanning laser ophthalmoscope (SLO). CDI measurements of the retrobulbar vessels included peak systolic velocity, end diastolic velocity, and the calculated resistance index. Arterio-venous passage time (AVP) in the superior and inferior temporal retina was calculated from the SLO angiograms. RESULTS. Neither dorzolamide nor latanoprost had any statistically significantly effect on HR or BP. Both drugs significantly lowered IOP without altering calculated ocular perfusion pressure (p<0.05). There was no statistically significant difference in any CDI measurement. Dorzolamide significantly decreased AVP time in the superior retina (p=0.011), while latanoprost did not (p=0.62). CONCLUSIONS. Dorzolamide, unlike latanoprost, significantly reduced AVP times in the superior temporal retina in normal tension glaucoma (NTG) patients.