Preliminary observations concerning treatment of visual discomfort and associated perceptual distortion.
A system for therapeutic precision tinting is described. Some individuals who are subject to perceptual distortion of text no longer perceive the distortion when the text has a particular colour. A simple colorimeter enables an observer to illuminate text with light of a particular chromaticity, varying first CIE 1976 hue angle (huv), then saturation (suv), and then luminance, to obtain a setting that maximizes visual comfort and reduces any perceptual distortion. The colorimeter setting is then matched by a combination of tinted trial lenses. The combination uses only two dyes at a time from a selection of seven, unless a dark lens is required, when a third neutral (grey) dye is added. The subject observes both text and a normal scene when wearing tinted trial lenses. A variety of trial lenses are compared including those that match the colorimeter setting and others with similar hue angle. Spectacle lenses are then tinted so as to have a spectral transmission identical to that of the chosen combination of trial lenses. Certain patients with reading disorders, eye-strain, headaches or photosensitivity epilepsy report benefit when wearing spectacles tinted according to the above techniques. The physiological basis for the therapeutic effects is uncertain, but may involve a selective impairment of luminance or colour-difference channels.
Wilkins
A
A
MRC Applied Psychology Unit, Cambridge, UK.
Milroy
R
R
Nimmo-Smith
I
I
Wright
A
A
Tyrrell
R
R
Holland
K
K
Martin
J
J
Bald
J
J
Yale
S
S
Miles
T
T
D000293:Adolescent; D002648:Child; D003119:Color Perception Tests; D003124:Colorimetry; D005139:Eyeglasses; D006801:Humans; D055095:Optics and Photonics; D010468:Perceptual Disorders / Q000628:therapy; D014786:Vision Disorders / Q000628:therapy*