Effects of Glaucoma Drugs on Ocular Hemodynamics in Glaucoma: Dorzolamide (Trusopt®) versus a Fixed Dorzolamide/Timolol Combination (Cosopt®)

Abstract

 

Purpose:

 

Reduced choroidal perfusion is hypothesized to play a role in the pathogenesis of normal tension glaucoma. Thus the impact of antiglaucomatous eye drops on ocular perfusion has been the focus of recent research and the subject of intensive investigations. The present study investigates whether topically applied dorzolamide or a fixed dorzolamide/timolol combination influence ocular perfusion in patients with glaucoma.

 

Methods:

 

Ocular hemodynamics were assessed by color Doppler imaging (CDI) shortly before and after a 3–5 week treatment with either dorzolamide or a fixed dorzolamide/timolol combination in the short posterior ciliary artery (SPCA) which supplies the optic nerve head with blood. n=15 eyes were enrolled in the dorzolamide group and n=16 eyes in the dorzolamide/timolol group.

 

Results:

 

Dorzolamide lead to an increase of peak systolic velocity in the SPCA in the range that was reported in the literature before. Systolic and diastolic blood flow velocities in the SPCA showed no significant alteration after the treatment with dorzolamide plus timolol. A detailed summary of the results is shown in the table; asterisk denotes statistical significance.

 

Conclusions:

 

Dorzolamide accelerates blood flow in the SPCA in systole. This effect seems to be reversed by timolol. The fixed dorzolamide/timolol combination acts in a hemodynamically neutral manner.  

 

Keywords: blood supply • pharmacology