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Abstract #5286 Published in IGR 1-2
Modulation of Heidelberg Retinal Flowmeter parameter flow at the papilla of healthy subjects: Effect of carbogen, oxygen, high intraocular pressure, and β-blockers
Haefliger IO; Lietz A; Griesser SM; Ulrich A; Schötzau A; Hendrickson P; Flammer JSurvey of Ophthalmology 1999; 43 (S1): S59-S65
The Heidelberg Retinal Flowmeter (HRF) is intended to assess ocular blood flow by scanning laser Doppler flowmetry. In the retina and possibly in the optic nerve head, carbogen increases blood flow, whereas pure oxygen or high intraocular pressure (IOP) decrease it. This study addresses whether, at the papilla of healthy volunteers, the HRF parameter flow is modulated by breathing 5% carbogen (5% carbon dioxide + 95% oxygen) for 7 minutes, breathing 100% oxygen for 7 minutes, increasing IOP to 50 mmHg with a suction cup, or decreasing IOP with a single topical ocular instillation of the ß-blockers 0.5% betaxolol (betoptic) or 0.5% timolol (timoptic). At the papilla (20 x 5?, 256 x 64 pixels), values of HRF parameter, flow (50 x 50) pixels, increased after carbogen (n=5, p<0.05), but decreased after oxygen (n=5, p<0.05) or IOP increase (n=5, p<0.01). Although IOP values were significantly reduced by betaxolol (n=9, p<0.05) and timolol (n=9, p<0.01), HRF values were only significantly decreased (n=9, p<0.05) after timolol. In conclusion, at the papilla of healthy volunteers, a positive correlation exists between changes in values of the HRF parameter, flow, and stimuli considered to modulate retinal and ONH blood flow. Furthermore, although of unknown clinical relevance, it appears that, in contrast to betaxolol, values of the HRF parameter, flow, at the papilla of healthy volunteers are significantly decreased after a single instillation of timolol.
I.O. Haefliger, Laboratory of Ocular Pharmacology and Physiology, University Eye Clinic Basel, Basel; Switzerland
Classification:
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)
