PURPOSE. To assess systemic and ocular vascular reactivity in response to warm and cold provocation in untreated patients with primary open-angle glaucoma an d normal control subjects. METHODS. Twenty-four patients with primary openangle glaucoma and 22 normal control subjects were subjected to a modified cold press or test involving immersion of the right hand in 40°C warm water followed by 4 °C cold water exposure, and finger and ocular blood flow were assessed by means of peripheral laser Doppler flowmetry and retinal flowmetry, respectively. Fing er and body temperature as well as intraocular pressure, systemic blood pressure , systemic pulse pressure, heart rate, and ocular perfusion pressure were also m onitored. RESULTS. The patients with glaucoma demonstrated an increase in diasto lic blood pressure (P=0.023), heart rate (P=0.010), and mean ocular perfusion pr essure (P=0.039) during immersion of the tested hand in 40°C water. During cold provocation, the patients demonstrated a significant decrease in finger (P=0.00 03) and ocular blood flow (the parameter velocity measured at the temporal neuro retinal rim area; P=0.021). Normal subjects did not demonstrate any blood flow o r finger temperature changes during immersion of the tested hand in 40°C water (P >0.05); however, they exhibited increases in systolic blood pressure (P=0.034 ) and pulse pressure (P= 0.0009) and a decrease in finger blood flow (P=0.0001) during cold provocation. In normal subjects, the ocular blood flow was unchanged during high and low temperature challenge. CONCLUSIONS. Cold provocation elicit s a different blood pressure, and ocular blood flow response in patients with pr imary open-angle glaucoma compared with control subjects. These findings sugges t a systemic autonomic failure and ocular vascular dysregulation in POAG patient s.
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