Ocular blood flow and oxygen delivery to the retina in primary open-angle glaucoma patients: the addition of dorzolamide to timolol monotherapy.

Abstract

PURPOSE:

To assess the effects of adding dorzolamide to timolol monotherapy on ocular haemodynamics and retinal oxygen saturation in patients with primary open-angle glaucoma (POAG).

METHODS:

Twenty-four patients (12 healthy, 12 with POAG) were treated with dorzolamide/timolol combination (DT) versus timolol maleate 0.5% twice daily in a randomized, crossover, double-blind study conducted over a period of 18 months. Patients received each treatment for 8 months then crossed over to the other treatment after a 1-month washout and second baseline. Goldmann applanation tonometry, Heidelberg retinal flowmetry (HRF), colour Doppler imaging (CDI) and retinal photographic oximetry were performed at each visit.

RESULTS:

DT significantly reduced intraocular pressure (IOP) in both glaucomatous [right eye (OD) -13.15%, left eye (OS) -14.43%; p < 0.036] and non-glaucomatous (OD -12.4%, OS -13.88%; p < 0.039) patients compared to timolol after 8 months of treatment. DT significantly reduced the number of zero blood flow pixels in the superior (-39.72%; p < 0.014) and inferior (-51.44%; p < 0.008) retina in the non-glaucomatous group and inferior retina in the glaucomatous group (-55.38%, p < 0.006). The continuation of timolol monotherapy from baseline did not change (p < 0.05) any measured parameter and neither treatment had a significant effect (p < 0.05) on retinal oximetry or CDI parameters.

CONCLUSION:

The addition of dorzolamide to timolol monotherapy decreases IOP and increases retinal blood flow in the superficial retinal vasculature in both glaucomatous and healthy patients following 8 months of treatment. The combination of increased retinal blood flow with consistent oxygen saturation may potentially increase oxygen delivery to the retina.

• Authors: Brent Siesky, Alon Harris, Larry Kagemann, Einar Stefansson, Lynne McCranor, Brian Miller, Jeremiah Bwatwa, Guy Regev, Rita Ehrlich
• Journal: Acta ophthalmologica (Acta Ophthalmol) Vol. 88 Issue 1 Pg. 142-9 (Feb 2010) ISSN: 1755-3768 [Electronic] England
• PMID: 19706018 (Publication Type: Comparative Study, Journal Article, Randomized Controlled Trial)

Chemical References

• Antihypertensive Agents
• Carbonic Anhydrase Inhibitors
• Sulfonamides
• Thiophenes
• Timolol
• dorzolamide
• Oxygen

Topics

• Adult
• Aged
• Aged, 80 and over
• Antihypertensive Agents (therapeutic use)
• Carbonic Anhydrase Inhibitors (therapeutic use)
• Cross-Over Studies
• Double-Blind Method
• Drug Therapy, Combination
• Eye (blood supply)
• Glaucoma, Open-Angle (drug therapy, physiopathology)
• Hemodynamics (drug effects)
• Humans
• Intraocular Pressure (drug effects)
• Laser-Doppler Flowmetry
• Middle Aged
• Oximetry
• Oxygen (metabolism)
• Regional Blood Flow (drug effects)
• Retina (metabolism)
• Retinal Vessels (diagnostic imaging, physiopathology)
• Sulfonamides (therapeutic use)
• Thiophenes (therapeutic use)
• Timolol (therapeutic use)
• Ultrasonography, Doppler, Color