Visual Psychophysics / Physiological Optics - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group – Visual Psychophysics / Physiological OpticsAdaptive Optics Measurements of Retinal Arterial WallThickness in both Normotensive and Hypertensive SubjectsJake Hillard 1 , Toco Y. Chui 1 , Dan A. Sapir 2 , Thomas Gast 1 , StephenA. Burns 1 . 1 School of Optometry, Indiana University, Bloomington,IN; 2 Medical School, Indiana University, Bloomington, IN.Purpose: To make precise measurements of vascular wall thicknessin the retinas of both systemically normotensive and hypertensiveindividuals using an adaptive optics scanning laser ophthalmoscope(AOSLO).Methods: We used the Indiana AOSLO, operated with a relativelylarge (10x the Airy disc) confocal aperture, displaced by more thanthe Airy disc radius. This imaging approach provides excellentimaging of the retinal vasculature, and gives a better visualization ofthe walls (Chui et al 2012). Images of retinal blood vessels rangingfrom capillaries to the largest retinal vessels were obtained in a groupof 6 normal subjects and 16 subjects with a history of hypertension.Vessels ranging in size from an inner diameter of 9 to 171 micronswere measured. Measurements were made using an image editingprogram and were repeated on each vessel 5 times. The lumens of thevessels were differentiated from the vessel walls by the motion oferythrocytes, within the lumens, readily seen on aligned videosequences.Results: Arterial walls and lumens were able to be measured in allsubjects and in almost all of the vessels chosen for analysis. Venouswalls were occasionally measurable in hypertensive but not in normalsubjects. Some arteries could not be measured due to shadowing orfocusing in a different plane although all tested individuals had atleast some measurable arteries. For both small arteries and arterioles(lumen diameters < 50 microns) and larger ones, the hypertensivesubjects had higher wall to lumen ratios (p< 0.02 , p