GB412081A - Improvements in eyeglasses for correcting ocular image differences - Google Patents

Abstract

412,081. Spectacle lenses. BROOKES, N. E., 1, Quality Court, Chancery Lane, London.-(Dartmouth College, Trustees of ; Hanover, New Hampshire, U.S.A.) Oct. 11, 1933, No. 28075. [Class 97 (i).] In order to compensate for differences between the sizes and/or shapes of the two images of a given object produced by a person's eyes, the dimensional relationship of the two images is changed by means of a lens or plate which deflects the incident light rays to such an extent as to render the images substantially equal. The correction device shown consists of a plate V constituting a lens of zero power and having curved surfaces S<1>, S<2> of substantially the same curvature. When this plate is placed in front of the eye 0 with its concave surface towards the eye, the refraction which the light rays undergo in passing through the plate has the effect of displacing the image of a point P in the object field from the point y to the point y', the displacement depending upon the distance of the point y from the axis MN of the eye. The plate then produces an increase in the size of the image without altering the power of the eye. Reduction of the image size can be effected by mounting the plate with its convex side towards the eye. The plate can be mounted in a spectacle frame, either alone or in conjunction with such lenses as are necessary to correct for refractive errors of the eye. When lenses are required, the use of a separate sizecorrecting plate may be avoided by modifying the shape of the lens by varying the radii of its surfaces without altering its power, so that the lens itself produces the necessary size correction as well as correcting the refractive errors.