Retinal arteriolar vascular reactivity in untreated and progressive primary open-angle glaucoma

Subha T. Venkataraman, Chris Hudson*, Rony Rachmiel, Yvonne M. Buys, Samuel N. Markowitz, Joseph A. Fisher, Graham E. Trope, John G. Flanagan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


PURPOSE. To determine (1) the magnitude of retinal arteriolar vascular reactivity to normoxic hypercapnia in patients with untreated primary open-angle glaucoma (uPOAG) or progressive (p)POAG and in control subjects and (2) the effect of treatment with 2% dorzolamide on retinal vascular reactivity in uPOAG. METHODS. The sample comprised 11 patients with uPOAG (after undergoing treatment, they became treated (t)POAG), 17 patients with pPOAG (i.e., manifesting optic disc hemorrhage), and 17 age-similar control subjects. The partial pressure of end-tidal CO2 (PETCO2) was stabilized at 38 mm Hg at baseline. After baseline (10 minutes), normoxic hypercapnia was then induced (15 minutes) with an automated gas flow controller. Retinal arteriolar and optic nerve head (ONH) blood hemodynamics were assessed. The procedures were repeated after treatment with 2% dorzolamide for 2 weeks in tPOAG. RESULTS. Baseline arteriolar hemodynamics were not different across the groups. In control subjects, diameter, velocity, and flow increased (P<0.001) in response to normoxic hypercapnia. There was no change in all three hemodynamic parameters to normoxic hypercapnia in uPOAG, whereas only blood flow increased (P=0.030) in pPOAG. Vascular reactivity was decreased in uPOAG and pPOAG patients compared with that in control subjects. After treatment with topical 2% dorzolamide for 2 weeks, the tPOAG group showed an increase in diameter, velocity, and flow (P±0.04) in response to normoxic hypercapnia. Similar trends were noted for ONH vascular reactivity. CONCLUSIONS. A reduced magnitude of arteriolar vascular reactivity in response to normoxic hypercapnia was shown in uPOAG and in pPOAG. Vascular reactivity improved after dorzolamide treatment in POAG.

Original languageEnglish
Pages (from-to)2043-2050
Number of pages8
JournalInvestigative Ophthalmology and Visual Science
Issue number4
StatePublished - Apr 2010
Externally publishedYes


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