REAL-TIME MEASUREMENT OF HUMAN OPTIC-NERVE HEAD AND CHOROID CIRCULATION, USING THE LASER SPECKLE PHENOMENON

A modification of a previously described instrument that used the lase r speckle phenomenon for noncontact two-dimensional analysis of the fu ndus tissue circulation was devised so that tissue circulation in the optic nerve head (ONH) or choroid of the human eye could be measured o n a real-time basis. The fundus was illuminated by a diode laser spot and the image speckle was recognized by an area sensor. A quantitative index of blood velocity, normalized blur (NB), was calculated by a:lo gistic board every 0.125 seconds for 7 seconds. Using this modified de vice, the average NE of the measurement field in the temporal ONH, fre e of visible surface vessels (NBONH), and that in the posterior choroi d (NBch) of normal human eyes were measured. The coefficients of repro ducibility of 1-minute interval measurements were 11.7% for the NBONH and 8.7% for the NBch (each, an average of 5 pulses), and those of 24- hour interval measurements were 13.0% (NBONH) and 9.7% (NBch). The pul satile component average of NBONH, was 38.4% of mean NBONH; of NBch, 2 6.6% of the mean NBch. (C) 1997 Japanese Ophthalmological Society.