Choroidal blood flow response to isometric exercise in glaucoma patients and patients with ocular hypertension

Abstract

Purpose: To analyze submacular choroidal blood flow (ChBF) response to isometric exercise in untreated patients with glaucoma and ocular hypertension.

Methods: ChBF was examined by means of confocal laser Doppler flowmetry during 5 minutes of baseline, during 90 seconds of isometric exercise with a Martin's vigorimeter and during 15 minutes of recovery. Values from one randomly chosen eye of 45 healthy subjects, the eye with more advanced damage in 45 primary open-angle glaucoma (POAG) patients, and the eye with higher native intraocular pressure in 45 patients with ocular hypertension (OHT) were acquired, and parameters of ChBF as well as blood pressure response were analyzed.

Results: Healthy eyes demonstrated higher ChBF at baseline than did the eyes in both the other groups (5126 ± 1487, 4186 ± 1011, and 4437 ± 1372 arbitrary units, ANOVA P = 0.003). Both mean and diastolic arterial blood pressures at baseline were lower in POAG patients than in those with OHT and healthy controls (P < 0.03); however, the response of mean blood pressure to isometric exercise was comparable across groups (P = 0.79). The ChBF response to exercise was stronger in the POAG group (ANOVA P = 0.02), it was twice as high as in the controls (+8.1% ± 8.0% vs. +3.7% ± 6.7%; P = 0.007) and borderline higher than in the OHT patients (+5.0% ± 8.0%; P = 0.051).

Conclusions: Baseline ChBF was lower in both the POAG and the OHT patients, compared with that in the controls. The stronger increase in ChBF in POAG patients in the face of an exercise-induced blood pressure increase indicates less active regulatory capacity in glaucoma patients.

Trial registration: ClinicalTrials.gov NCT00430209.