DEVICE AND METHOD FOR DETECTING AND MEASURING RIGHT-EYE/LEFT-EYE ASYMMETRY BETWEEN BLUE-CONE FREE ZONES OF THE FOVEA OF EACH RETINA IN HUMANS

摘要

The invention relates to a device for detecting and measuring never previously observed right-eye/left-eye asymmetry between blue-cone free zones at the centre of the fovea of each retina, and to a method that allows an ellipticity coefficient to be attributed to each retina. The device especially comprises a frosted screen (12) illuminated by a source (11) emitting white light having a spectrum similar to that emitted by a blue sky. This screen (12) is placed at the exit of a conical system (13), of about 2 m in length. Moving a double green-and-blue filter (14, 15) sideways in front of the eye allows a light-green entoptic image of about 2 cm in diameter to be viewed through the filter on the screen, this image being due to the absence of blue cones at the centre of the retina. A control device consisting of another blue filter may be inserted into the system, the entoptic image then appearing pink when the filter is rapidly moved away from the eye. A graphical tablet (19) connected to a computer (18) makes it possible for the observer to trace the profile of the blue-cone free zone of the fovea of each retina, and thus to obtain two records called foveagrams. In addition, measuring the degree of ellipticity for each eye allows the degree of right-eye/left-eye asymmetry to be qualified. The device and method for measuring the degree of ellipticity of each zone are intended to qualify ocular dominance stability or instability, which may be crucial for eyesight-related problems and dyslexia in particular.