TY - JOUR T1 - Reproducibility of circadian retinal and optic nerve head blood flow measurements by Heidelberg retina flowmetry JF - British Journal of Ophthalmology JO - Br J Ophthalmol SP - 348 LP - 353 DO - 10.1136/bjo.2003.024885 VL - 88 IS - 3 AU - C P Jonescu-Cuypers AU - A Harris AU - K U Bartz-Schmidt AU - L Kagemann AU - A S Boros AU - U E Heimann AU - B H Lenz AU - R-D Hilgers AU - G K Krieglstein Y1 - 2004/03/01 UR - http://bjo.bmj.com/content/88/3/348.abstract N2 - Background/aim: The Heidelberg retina flowmeter (HRF) is designed to measure retinal capillary blood flow. Previous studies however showed weak reproducibility of data. The intraindividual reproducibility of circadian HRF measurements was examined in healthy subjects in three locations of the retina. Methods: 36 healthy volunteers (27.3 (SD 4.3) years) were examined by HRF seven times a day (t0–t6). Using a default window of 10×10 pixels, three consecutive measurements were performed in three precise focusing planes: superficial, intermediate and deep layer, peripapillary retina, neuroretinal rim and cup, respectively. Images of identical tissue locations identified by capillary landmarks of each layer were selected to quantify the retinal microcirculation of each volunteer. Means and standard deviations of all flow results of a given subject were calculated, at t0–t6 and the coefficients of variation as a measure of reproducibility. Results: The coefficients of variation ranged between 8.4% and 41.0% in the superficial layer (mean 19.8% (SD 8.4%)), 10.6%, and 43.0% in the intermediate layer (mean 24.0% (SD 8.4%)), and 9.9% and 84.0% (mean 29.6% (SD 15.8%)) in the deep layer. Conclusions: These data show the best reproducibility of measurements in the superficial layer followed by the intermediate and the deep layer. Clinically, this is an unsatisfactory intraindividual reproducibility of flow values in each studied layer. ER -