RETINAL BLOOD-FLOW MEASUREMENTS IN BRANCH RETINAL VEIN OCCLUSION USING SCANNING LASER-DOPPLER FLOWMETRY

PURPOSE: To determine capillary blood flow measurements in eyes with b ranch retinal vein occlusion using a scanning laser Doppler flowmeter. METHODS: Retinal capillary blood flow in branch retinal vein occlusio n areas and corresponding ipsilateral nonbranch retinal vein occlusion areas, 11 equivalent areas of the contralateral fellow eye of 12 cons ecutive untreated branch retinal vein occlusion patients, and 16 eyes of 11 age-matched normal control subjects were measured with scanning laser Doppler flowmetry. A template consisting of eight squares, each with a field of 100 x 100 mu m (10 x 10 pixel) with space interval of 500 mu m equidistant horizontally and vertically was used to obtain bl ood flow measurements in all subjects. Mean blood volume, flow, and ve locity were obtained by averaging the mean values measured in each fie ld. We avoided measurement over large retinal vessels to prevent the a liasing artifact of blood cells from moving faster than the sampling f requency. RESULTS: Branch retinal vein occlusion areas have significan tly decreased microvascular blood volume (P =.0009), flow (P =.02), an d velocity (P =.016) compared with ipsilateral nonbranch retinal vein occlusion areas in the same eye. Branch retinal vein occlusion areas a lso have decreased blood volume (P =.001), flow (P =.0042), and veloci ty (P =.0044) compared with areas of contralateral fellow eyes of bran ch retinal vein occlusion subjects. Branch retinal vein occlusion area s have significantly decreased blood volume (P =.0012), flow (P =.008) , and velocity (P =.02) compared with age-matched normal areas. CONCLU SION: Average retinal blood volume, flow, and velocity in areas of bra nch retinal vein occlusion are significantly lower than in healthy ret inas. The ability to noninvasively measure hemodynamic changes in the retinal capillary bed may be relevant to development of new therapies for retinovascular disease. (Am J Ophthalmol 1998;126:683-690. (C) 199 8 by Elsevier Science Inc. All rights reserved.).