[An apparatus using laser speckle phenomenon for noncontact two-dimensional analysis of microcirculation in optic...

The previously reported apparatus using the laser speckle phenomenon for noncontact two-dimensional analysis of the fundus peripheral circulation was improved so that peripheral circulation in the optic nerve head (ONH) or choroid in human eyes can be measured on a real-time basis. The fundus was illuminated by a diode laser spot and its image speckle was detected with an area sensor. The NB value, a quantitative index of blood velocity, was calculated by the logic board every 0.125 sec successively for 7 sec. Using this apparatus, the NB averaged over the measurement field located in the temporal site of ONH, free of visible surface vessels (NBONH), and that located in the posterior choroid (NBCh) were measured in normal human eyes. The coefficients of reproducibility of 5-minute interval measurements were 11.7% for the NBONH averaged over 5 pulses (mean NBONH) and 8.7% for the NBONH averaged over 5 pulses (mean NBCh), and those of 24-hour interval measurements were 13.0% for the former and 9.7% for the latter, respectively. The average of pulsatile component of NBONH was 38.4% of mean NBONH and that of NBCh was 26.6% of mean NBCh.