Ocular fundus images with confocal scanning laser ophthalmoscopy in the dog, monkey and minipig

Abstract

Confocal scanning laser ophthalmoscopy (CSLO) is a new technique that enables ocular fundus image recording and retinal dynamic angiography to be performed. The ocular fundus image is acquired sequentially, point by point, and is reconstructed on a video monitor at the rate of 25 images per second. The feasibility of performing both ocular fundus image recordings and retinal angiography image recordings were tested on two dogs, two monkeys and two minipigs using a 40 degrees field I + Tech CSLO. Fundus area of each dog, monkey and minipig were examined without any additional optical devices. The ocular fundus and angiography images were recorded, stabilized and analyzed under the same conditions. For each species, all images were easily recorded without any additional optical device in a lighted room and the morphology of the retinal images generated was similar to those obtained with a camera or angiography of higher resolution. Capillary phase or venous times are presented. Image recording at 25 frames/second enabled more retinal dynamics to be demonstrated than with use of regular angiography. This technique is noninvasive and easy to perform if the eye is fixed and eyelids maintained open. It also allows exploration of retinal microvascularization and could be utilized for clinical, pharmacologic and toxicologic investigations as well.

Clinical Signs and Diagnosis of the Canine Primary Glaucomas

“…17). 46,47 Multiple confocal slices are acquired at different focal planes, allowing for a detailed 3-dimensional reconstruction of the optic disc and adjacent peripapillary retina. Three consecutive scans are acquired in approximately 2 seconds, making this a very rapid method for evaluation of the optic disc.…”

SLO angiography: arterio‐venous filling times in monkey and minipig

“…The cSLO (I + Tech, Clermond‐Ferrand, France) used in this study 13 (Fig. 1) is composed of two laser illumination beams: an infrared light‐emitting diode beam (780 nm) and an argon beam (488 nm) which allows a 40° field recording of retinal images in a lighted environment.…”

“…Images were recorded, stabilized and analyzed under the same conditions. The recorded images (25 frames/s) were analyzed by a personal computer‐base image analysis system 14 and NIH image 1.62 freeware as previously described 13 . The arterial and venous gray levels were measured on successive stabilized images as a function of time and evaluated by visualization on a screen (scale: 256 pixels, acuracy ±1 pixel).…”

Exploration de la fonction visuelle sensorielle chez l'animal : Deuxième partie : ERG chez l'animal

“…Chez l'homme, l'utilisation de stimulations rétiniennes localisées est justifiée par l'étude de la zone maculaire, mais chez l'animal (à l'exception des primates non humains), cette zone n'existe pas et, par conséquent, la principale source de stimulation est le flash. Néanmoins, dans certains cas, la stimulation d'une partie restreinte de la rétine peut être effectuée soit au moyen d'un ophtalmoscope laser à balayage (SLO) (ROSOLEN et al, 2001), soit de façon plus complexe et délicate, directement ou indirectement (projection sur un écran tangentiel). Dans ces deux derniers cas, il faut mesurer initialement la réfraction, puis corriger les défauts réfractifs et enfin projeter sur la rétine la stimulation après correction de ces défauts visuels.…”