Early attempts to modify or enhance the color of one's eyes utilized colored contact lenses with a simple solidly colored area that covered the iris portion of the eye. However, contact lenses with this type of opaque coloring imparted a very unnatural appearance. Other types of colored contact lenses were developed, such as Wichterle, U.S. Pat. No. 3,679,504, which discloses an opaque lens having an iris of more than a single color artistically drawn or photographically reproduced. However, such lenses did not look natural and as such never achieved commercial success. Other attempts to produce an opaque lens with a natural appearance are disclosed in. U.S. Pat. No. 3,536,386, (Spivak); U.S. Pat. No. 3,712,718 (LeGrand), U.S. Pat. No. 4,460,523 (Neefe), U.S. Pat. No. 4,719,657 (Bawa), U.S. Pat. No. 4,744,647 (Meshel et al.), U.S. Pat. No. 4,634,449 (Jenkins); European Patent Publication No. 0 309 154 (Allergan) and U.K Patent Application No. 2 202 540 A (IGEL).
Commercial success was achieved by the colored contact lens described in Knapp (in U.S. Pat. No. 4,582,402) which discloses a contact lens having, in its preferred embodiment, colored, opaque dots. The Knapp lens provides a natural appearance with a lens that is simple and inexpensive to produce, using a simple one-color printed dot pattern. Although the intermittent pattern of dots does not fully cover the iris, it provides a sufficient density of dots that a masking effect gives the appearance of a continuous color when viewed by an ordinary observer. Knapp also discloses that the printing step may be repeated one or more-times using different patterns in different colors, since upon close examination the iris is found to contain more than one color. The printed pattern need not be absolutely uniform, allowing for enhancement of the fine structure of the iris. The one-color Knapp lenses currently achieving commercial success have their dots arranged in an irregular pattern to enhance the structure of the iris. However, neither the Knapp commercial lenses, nor the Knapp patent disclose or suggest how one would arrange a pattern of dots having more than one color to achieve a more natural appearance.
Various efforts have been made to improve on the Knapp lens. U.S. Pat. No. 5,414,477 to Jahnke discloses the application of the intermittent ink pattern in two or more portions of distinct shades of colorant to provide a more natural appearance.
Other attempts to create a more natural appearing lens include U.S. Pat. No. 5,120,121 to Rawlings, which discloses a cluster of interconnecting lines radiating from the periphery of the pupil portion to the periphery of the iris portion. Further, European Patent No. 0 472 496 A2 shows a contact lens having a pattern of lines that attempts to replicate the lines found in the iris.
Despite these efforts, the contact lens industry continues to seek a low-cost, colored lens that can enhance or modify the eye color, while providing the depth and texture that is inherent in the human iris.