COMPARISON OF ENTOPITIC AND FUNDUS CAMERA IMAGES OF THE HUMAN RETINAL BLOOD VESSELS

Title COMPARISON OF ENTOPITIC AND FUNDUS CAMERA IMAGES OF THE HUMAN RETINAL BLOOD VESSELS
Author, Co-Author Hui Zhang, Arthur Bradley, Raymond Applegate
Topic
Year
1993
Day
Sunday
Program Number
Poster 82
Room
Exhibit Hall
Affiliation
Abstract Details of the retinal vasculature are typically recorded using a fundus camera. However, patients can entoptically view their own retinal vessels. In this study, using entoptic methods, detailed drawings of retinal vessels were made by six normal observers. These were compared with color fundus photographs taken with a Cannon CF-60UV fundus camera. Two methods for entoptic viewing were used: (1) a rotating light imaged onto the sclera 6mm from the temporal limbus (Trans-scleral method: TS), and (2) a Maxwellian-view optical system projected a small rotating short wavelength source into the pupil plane (Through-the-pupil method: TP). The TP technique had an optically limited field of 7.5 deg., and subjects reported a high density of vessels within this field. The TS technique provided visible shadows of the retinal vessels over a much larger area (range 30-60 degrees) centered on the macula. The perifoveal capillaries that, in most subjects, define the foveola avascular zone (FAZ) were clearly visible with the TP technique. In three eyes, small capillaries were seen running through the fixation point (no FAZ present). Three of the subjects could also see their FAZs using the TS method. Vessels emerging from the optic nerve head were visible with the TS method and subjects could see the superior and inferior temporal retinal arteries and veins, and a large number of branching vessels leading to and surrounding the macula. Although specific capillary details could not be drawn, a visible "texture" was observed between the larger vessels in the macula. Using isotropic scaling and rotations, the digitized drawings were matched to digitized fundus photographs. In spite of local position and scaling discrepancies, the drawings correlate with the individual fundus photographs. Subjects missed most of the smaller arteries and veins in the peripheral retina (eccentricities > 10 degrees), but, within the central 5 degrees, were able to see more vascular detai
Affiliation of Co-Authors
Outline