Imaging retinal densitometry with a confocal Scanning Laser Ophthalmoscope.
We describe a novel use of the Scanning Laser Ophthalmoscope (SLO), viz. as an imaging retinal densitometer. In our SLO a helium-neon or an argon laser beam is moved in a raster pattern over the retina; the reflected light is descanned (confocal SLO) and collected by a photomultiplier. Images of the fundus subtending 22 by 18 deg are displayed on a TV monitor. Single frames taken with 514 nm light were stored in a computer in arrays of 256 by 256 pixels and density differences between dark adapted and bleached images were calculated. With a full bleach density differences of about 0.35 were found in the center of the fovea; at retinal eccentricities of 15-20 deg we found 0.15. After selective bleaching with 633 nm light substantial density differences were only seen in the foveal area. We conclude that the confocal SLO is a very suitable instrument for imaging fundus reflectometry.
van Norren
D
D
Royal Netherlands Eye Hospital, Utrecht.
van de Kraats
J
J
D003720:Densitometry / Q000295:instrumentation*; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005654:Fundus Oculi; D006801:Humans; D007834:Lasers; D019721:Ophthalmoscopes