J. Kiryu et al., LOCAL RESPONSE OF THE PRIMATE RETINAL MICROCIRCULATION TO INCREASED METABOLIC DEMAND INDUCED BY FLICKER, Investigative ophthalmology & visual science, 36(7), 1995, pp. 1240-1246
Purpose. To study the response of the macular circulation to a local i
ncrease in metabolic demand created by a flickering source of illumina
tion. Methods. Laser-targeted angiography (release of a fluorescent dy
e from heat-sensitive liposomes using a laser pulse) was used to study
, in subhuman primates, changes in hemodynamic parameters of the retin
al circulation that were induced by a flickering source of illuminatio
n. Changes in the macular macrocirculation were compared with those in
the macular microcirculation and were evaluated at various distances
from the foveola. Results, In response to monochromatic light flicker,
the blood flow in retinal arteries increased by 30%. The response of
the microcirculation was not homogeneous. It showed a maximum increase
in the mid-perifoveal region where there is an increase in ganglion c
ells and nerve fibers. Interestingly, the maximum change in the index
representing capillary blood now exceeded the blood flow change in the
artery (P < 0.08). Conclusions, A stimulus expected to cause increase
d metabolic demand results in a regulatory response by the retinal mic
rocirculation. This response shows spatial variations that correspond
with known variations in retinal anatomy. The authors propose that a r
edistribution of blood can occur between the capillary layers to fulfi
ll high metabolic demands by neuronal tissue remote from the choroid.