Abstract: A colored contact lens for use as a trial lens, consisting of a circular plastic lens having a convex outer surface and comprising a clear limbal ring (1) at the outer edge of the lens, a clear pupillary part (2) in the middle of the lens and an iris ring (3) between the limbal ring and the pupillary part, the iris ring being provided with a continuous pattern formed by a coloring agent. According to the invention, the iris ring comprises a visually perceptible discontinuity area that breaks the continuous pattern.

Abstract: Method for producing a raster surface for use in the coloring of a contact lens, in which method an image surface consisting of picture elements is selected, the image surface is subjected to a tonal reduction operation and a threshold tone value is defined for it, and picture elements darker than the threshold value are made black while picture elements lighter than the threshold value are made white, and the black-and-white image surface is subjected to radial stretching in relation to a given point, the position of said point corresponding to the center of the contact lens to be treated, whereupon a raster pattern for the image to be created on the contact lens can be produced using the image surface, i.e. raster pattern thus obtained.

Abstract: A colored contact leas for use as a trial lens, consisting of a circular plastic lens having a convex outer surface and comprising a clear limbal ring (1) at the outer edge of the lens, a clear pupillary part (2) in the middle of the lens and an iris ring (3) between the limbal ring and the pupillary part, the iris ring being provided with a continuous pattern formed by a coloring agent. According to the invention, the iris ring comprises a visually perceptible discontinuity area that breaks the continuous pattern.

Abstract: The invention relates to a procedure for staining a contact lens, wherein at least part of the surface of the lens consisting of a polymer containing hydroxyl and/or carboxyl groups is coated with a color coating containing as polymer-cross-linking agent a compound with at least two urethane groups or a mixture of such compounds, and urethane exchange is effected for causing cross-linking of polymers, by reacting the urethane groups with the hydroxyl and/or carboxyl groups of the bonding agent polymer and of the lens polymer.