Evaluation of retinal haemodynamics and retinal function after application of dorzolamide, timolol and latanoprost in newly diagnosed open-angle glaucoma patients.
OBJECTIVE
The purpose of this prospective, randomized, cross-over study was to investigate and compare the microcirculatory effects of timolol, dorzolamide and latanoprost in newly diagnosed primary open-angle glaucoma (POAG) patients. Haemodynamics were assessed using fluorescein angiography by means of a scanning laser ophthalmoscope (SLO). Visual function and visual field indices were evaluated during all drug treatment phases.


METHODS
Fourteen patients with newly diagnosed POAG (age 55 +/- 7 years; 10 male, four female) were recruited for the study. At baseline examination, blood pressure, heart rate, intraocular pressure (IOP), SLO angiograms, and contrast sensitivity (CS) were analysed. Patients then randomly received timolol, dorzolamide or latanoprost treatment for 4 weeks. Patients then returned and all procedures were repeated and assessed. Arteriovenous passage times (AVPs), peripapillary arterial and venous diameters were assessed from SLO angiograms, using digital image processing. Calculated ocular perfusion pressure was determined for each treatment phase.


RESULTS
Intraocular pressure was significantly lowered by each drug compared to baseline (p < 0.0001). Arteriovenous passage times were significantly shortened after dorzolamide application compared to baseline (p = 0.009), whereas neither timolol nor latanoprost treatment resulted in significant AVP changes. Peripapillary arterial and venous diameters, systolic and diastolic blood pressure, heart rate and ocular perfusion pressures were not significantly altered during any treatment phase. Contrast sensitivity testing at 6 cycles/degree (c.p.d.) revealed a significant rise after dorzolamide compared to timolol (p = 0.007).


CONCLUSIONS
Our results suggest that dorzolamide treatment significantly shortened AVP times in newly diagnosed open-angle glaucoma patients, whereas timolol and latanoprost had no significant effect. Given that prolonged AVP times have been associated with disease progression in glaucoma; dorzolamide treatment may benefit optic nervehead preservation by increasing ocular perfusion.
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D001158:Arteries; D001794:Blood Pressure / Q000187:drug effects; D002257:Carbonic Anhydrase Inhibitors / Q000627:therapeutic use*; D015350:Contrast Sensitivity / Q000187:drug effects; D018592:Cross-Over Studies; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy* / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D000077338:Latanoprost; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009887:Ophthalmoscopy; D011461:Prostaglandins F, Synthetic / Q000627:therapeutic use*; D012039:Regional Blood Flow / Q000187:drug effects; D012171:Retinal Vessels / Q000187:drug effects* / Q000503:physiopathology*; D013449:Sulfonamides / Q000627:therapeutic use*; D013876:Thiophenes / Q000627:therapeutic use*; D013999:Timolol / Q000627:therapeutic use*; D014680:Veins
D000319:Adrenergic beta-Antagonists; D002257:Carbonic Anhydrase Inhibitors; D011461:Prostaglandins F, Synthetic; D013449:Sulfonamides; D013876:Thiophenes; D000077338:Latanoprost; D013999:Timolol; C062765:dorzolamide