CORRELATING PULSATILE OCULAR BLOOD FLOW WITH CHROMATIC ATTRIBUTES OF THE OCULAR FUNDUS IN MAN

Title CORRELATING PULSATILE OCULAR BLOOD FLOW WITH CHROMATIC ATTRIBUTES OF THE OCULAR FUNDUS IN MAN
Author, Co-Author Marc O.D., John Lovasik O.D.
Topic
Year
1992
Day
Sunday
Program Number
2:30 pm
Room
Scotland B
Affiliation
Abstract The objective of our study was to correlate changes in the chromaticity (hue, saturation, brightness) of the ocular fundus with the choroidal pulsatile ocular blood flow (POBF). Transient changes in the fundus and optic nerve head (ONH) coloration as well as the POBF were effected in five adult volunteers by stepwise changes in the ocular perfusion pressure (OPP). The OPP was decreased by up to 50% in steps of 10% for 1 min. intervals by increasing the intraocular pressure (IOP) via scleral suction (SS). In the first part of the study, fundus photographs (N=7) were taken with a Topcon TRC-50VT camera at 1 min. intervals for baseline, at each decrement in the OPP (N=4), immediately after SS was stopped (N=1), and during a 3 min. recovery period (N=3). In the second part of the study, POBF measurements were taken with a Langham ocular blood flow system for the same test conditions and at the same times that fundus photos were taken. For analysis, the color fundus slides were magnified, cropped for the optic nerve head (ONH) area, and digitized. A Nikon MicroAnalyst system was used to analyze the chromatic attributes of the ONH. The ONH coloration did not change widely during baseline. Both ONH coloration and POBF changed systematically during altered OPP. The ONH redness and the POBF were inversely correlated. The ability to modify the chromatic attributes of the ONH for even small changes in the OPP suggests that the vascular network(s) supplying the ONH are not well autoregulated. The technical aspects of the methodology are presented, and the theoretical and clinical implications of our findings are discussed.
Affiliation of Co-Authors
Outline