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Publication numberUS3586423 A
Publication typeGrant
Publication dateJun 22, 1971
Filing dateJun 24, 1970
Priority dateJun 24, 1970
Publication numberUS 3586423 A, US 3586423A, US-A-3586423, US3586423 A, US3586423A
InventorsHarry I Zeltzer
Original AssigneeHarry I Zeltzer
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of improving color discrimination
US 3586423 A
Abstract  available in
Images(3)
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Claims  available in
Description  (OCR text may contain errors)

United States Patent [72] Inventor Harr l. Zeltzer 9 Rumford. Lexington. Mass. 02173 [2|] Appl. No. 49.582

[22] Filed June 24, 1970 [45] Patented June 22, 197i Continuation-impart of application Ser. No. 857,543, Sept. 12, 1969, now abandoned which is a continuation-in-part of application Ser. No. 462,068, June 7, 1965, now abandoned.

[54] METHOD OF IMPROVING COLOR DISCRIMINATION 3 Claims, No Drawings [52] U.S.Cl 351/39, 351/41, 351/44,?151/162 [5 1] Int. Cl G02c 7/10,

50 FieldofSearch .35l/26,35, 39,4l,44,162,l63

[561 References Cited FORElGN PATENTS 617 I877 GreatBritain 351/41 1,370,642 7/1964 France 351/162 Primary Examiner-David Schonberg Assistant Examiner.lohn W. Leonard Attorney-Joseph Zallen ABSTRACT: A method and device are described for improving color discrimination in persons having a substantial amount of deficiency in their ability to discriminate between red and green colors, commonly referred to as color blindness." The invention comprises applying to one eye only a corneal contact lens transmitting light substantialiy only in the red zone and leaving the other eye either naked or with its customary refractive correction, if any.

METHOD OF IMPROVING COLOR DISCRIMINATION This is a continuation-impart of my prior copending Pat. application, Ser. No. 857,543, filed Sept. 12, 1969 now abandoned, which in turn was a continuation-in-part of my then copending Pat. application, Ser. No. 462,068, filed June 7, 1965 and now abandoned.

BACKGROUND OF INVENTION This invention relates to a method for improving color discrimination. In particular, it relates to a method and device for improving color discrimination in persons who are red-green color deficient:

lt is generally believed that a person with normal color vision is able to discern an uninterrupted series of hues from red of about 760 millimicrons to violet of about 380 millimicrons with no black, grey or white areas. Persons with normal color vision clearly differentiate between the seven ordinary hues of red, orange, yellow, green, blue, indigo and violet.

However, according to some authorities, approximately 8 percent of males have a vision defect known as color discrimination deficiency or color blindness, a lack of a part of the neural apparatus necessary for normal color vision. Such neural defects are not completely understood. it is generally agreed that the most common type of color blindness is the inability to distinguish between red and green, known as redgreen color blindness. A person having such color blindness has great difficulty in distinguishing brown from green and sees various shades of red (such as pink) as grey. Such redgreen color blindness has been a great handicap to the persons involved, particularly with respect to their occupations, wherein color is a growing form of object identification. Further, colorblind persons, of whom there are about 8 million in the United States, are a hazard to themselves and to others, particularly in automobile driving and in hunting.

This problem of color discrimination deficiency has been reported and studied for many years. However, no one, to my knowledge, has ever suggested or proposed any method or device that would enable a person who had red-green color discrimination deficiency to improve it to any practical or substantial extent. Thus, although proposals have been made in the past to improve the ability of such persons to distinguish between red and green colored signal lights, no method or device has heretofore been proposed to improve the ability of such persons to discriminate between such colors in their everyday normal existence.

One object of the present invention is-to provide a method and device of improving color discrimination among persons having color discrimination deficiency to such an extend that use of the method or device can extend for a full day, including nighttime without inhibiting the mobility of the person and without interfering with his normal everyday tasks.

Further objects and advantages of this present invention will be apparent from the description and claims which follow.

SUMMARY OF INVENTION The invention comprises the use on one eye only of a corneal contact lens transmitting light substantially only in the red zone, with the other eye remaining naked or having its customary refractive correction, if any. The lens should be as thin as possible to avoid substantial loss of visual acuity. Although this single red corneal contact lens can be used with either the dominant or nondominant eye, I have noted that placing the lens on the nondominant eye appears to be more comfortable for the user.

When such a lens is worn in this fashion, a patient who could not hitherto pass the lshihara test wherein red and green spot figures are used, was now able with my invention to pass this test and distinguish among brown, green, red and pink objects, which he had hitherto been unable to do. The lens can be worn either day or night or both with no special requirements except those of cleanliness and removal when sleeping nonnally associated with contact lenses. The use of this lens V with or without spectacles.

does not interfere with the persons mobility or his performance of ordinary functions such as walking, driving, writing, reading or working, whether under normal light or artificial light. The use of my invention does not interfere with binocular vision.

The single red corneal contact lens of this invention can be made so as to incorporate a desired refractive correction, or it can be used with a spectacle lens having the correction for that same eye or the refractive correction can be divided between the contact lens and the spectacle lens. The other eye, not covered with a red contact lens, can have required refractive correction in the form of a conventional contact lens or spectacle lens or both.

For example, a color deficient person who is without refractive error but requires reading glasses (spectacle lenses), as in presbyopia could use reading glasses in conjunction with the single red corneal contact lens of this invention. For color deficient persons with binocular refractive errors, the other eye can have a conventional corrective corneal contact lens I have found by experimentation that thickness is a factor which limits the utility of a colored contact lens made in accordance with this invention. Thus, if the eye requires correction, the resultant contact lens may be so thick as to be overly dark for effective use. Accordingly, in such a case, a single red contact lens having no correction would be used in conjunction with a spectacle lens having the desired refractive correction. in this manner, the red contact lens may be kept thin enough to permit sufficient visual acuity. in general, the acuity should be at least 20/40 so that stereopsis is not lost. I have further found that the amount of light absorption by the contact lens of this invention also has an efiect on its utility. Thus, if the lens absorbs more than approximately 86 percent of the light, that is to say has light transmission of less than approximately 14 percent, binocular vision is affected. Further, if the amount of light absorption is less than approximately 60 percent, that is to say the transmission is higher than about 40 percent, color discrimination ability begins to decrease. These percentages might be better understood if one notes that a plain contact lens has about 10 percent loss or 90 percent transmission, while a lightly tinted lens has about 30 percent absorption or 70 percent transmission.

Although the corneal contact lens of this invention can be made from a variety of materials, I prefer to use clear transparent plastic materials such as the polymethacrylate resin group. An example of such a resin which I have found useful is polymethylmethacrylate.

It is noted that the red contact lens of this invention is used monocularly. Thus, the uncovered" eye receives a colordeficient image while the lens-covered eye receives an image which is differently shaded. The individual goes through a brief self-learning process in the true color. Thus, for example, the typical color discrimination deficient person cannot tell green from brown. From experiments with my patients, I have determined that with my invention the person sees green darker and brown lighter.

The uncovered" eye is an important factor in this invention, since it receives certain colors correctly which are obscured in the eye covered with the single red contact lens. I have found that each eye compensates for the disability of the other by a process which is a form of rectinal rival," a phenomenon of the visual mechanism.

Although the single red corneal contact lens of this invention can be used generally with persons deficient in color discrimination, there are certain contra-indicators. Thus, the lens of this invention should not be used where there is corneal pathology such as keratitis or where there are other diseases of the eye wherein the use of conventional corneal contact lenses are contra-indicated. Further, the single corneal contact lens of this invention would not be expected to improve color perception in persons who have amblyopia, strabismus or monocular vision.

SPECIFIC EXAMPLE OF INVENTION In one example of my invention, a contact lens was used which was made of red polymethacrylate. The lens had a radius of 8.23 mm, a diameter of 9.0 mm. and a thickness of 0.23 mm. lt had a peripheral bevel of ll.00/0.3, a secondary curve of 9.00/07 and an optic zone of 8.00. The lens transmitted substantially only in the red zone with practically no transmission below about 590 millimicrons, a peak at about 624 millimicrons, a range of about 590 to 700 millimicrons and an absorption of about 86 percent.

l fitted a patient with this single red contact lens in only one eye, namely his nondominant eye, leaving the dominant eye with no lens or uncovered. The patient indicated that he could now clearly study and decode color bands on resistors at a normal reading distance with average illumination and distinguish among red, brown and green. Prior to this time, although he had good visual acuity, he had always been colorblind and in particular completely unable to distinguish between red and green with, for example, brown looking like green and the various shades of red, as for example pink, appearing grey.

When the patient did not wear the lens, he reverted back to his original colorblind state but when he wore the lens, he always had this new ability to distinguish among red, brown and green. The lens did not in any way interfere with the patient's mobility and enabled him to continue to work at his job.

I wish to make it clear that while my experiments have shown that a single thin red colored corneal lens applied to one eye with the other eye uncovered will produce a practical, useful and substantial improvement in the' ability of a colorblind person to improve his color discrimination, the use of two such lenses, one in each eye, does not produce this desired effect but instead distorts colors, such as orange.

1 wish to also point out that a spectacle lens made of the same material as the corneal contact lens of this invention cannot be used as a substitute for the corneal contact lens, First, it would be exceedingly difficult to fabricate a spectacle lens of the same material and thickness because such a lens of, for example, 0.23 mm. thickness would be exceedingly fragile and difficult to form with accuracy. Even if such a spectacle lens were used in place ofa corneal contact lens, it would provide significantly smaller improvement in color discrimination. When such a spectacle lens was made of the same material but of a minimum thickness to make it feasible, as for example, 0.5 mm., the images were blurred and the colors less distinguishable than without any lens. I have further found that when such spectacle lenses were used for both eyes, overall vision was seriously impaired and certain colors were distorted such as orange.

I claim:

1. A method for improving color discrimination in a person deficient in color discrimination comprising the step of applying to one eye only a thin corneal contact lens transmitting light substantially only in the red zone and having between approximately l4 and 40 percent light transmission and substantially no transmission below approximately 590 millimicrons, the other eye being left uncovered except for the optional use of a spectacle lens, conventional corneal contact lens, or a combination thereof to provide a desired refractive correction for that eye.

2. The method of claim 1 wherein a spectacle lens having a desired refractive correction is used in conjunction with said red contact lens.

3. The method of claim 1 wherein said red lens is made of a polymethacrylate resin and has a thickness of approximately 0.23 millimeters.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4102567 *Sep 13, 1976Jul 25, 1978American Optical CorporationMaterial for fabrication of artificial intraocular lenses and hard contact lenses
US4300819 *Nov 7, 1979Nov 17, 1981Taylor Donald EEyeglasses for aiding color blind viewers
US5363151 *Oct 3, 1991Nov 8, 1994Biays Alice De P TColor correction for improved vision through water and other environments
US5363152 *Dec 3, 1992Nov 8, 1994Reed Iii Clurin BSelective color enhancement optical glasses
US5617154 *Oct 28, 1994Apr 1, 1997FlexlensLight filtering contact lens
US5774202 *Aug 18, 1993Jun 30, 1998Coloryte Hungary Optikai Kutato, Fejleszto Es Gyarto ReszvenytarsasagMethod and optical means for improving or modifying color vision and method for making said optical means
US5846457 *Mar 31, 1997Dec 8, 1998Hoffman; William C.Light filtering contact lens method
US5917573 *Nov 26, 1997Jun 29, 1999Davis; James KennethOptical device for aiding color-blind persons in distinguishing colored objects
US6132044 *Nov 20, 1998Oct 17, 2000Luxottica Leasing S.P.AFilter for a special purpose lens and method of making filter
US6811258Jun 23, 2003Nov 2, 2004Alan H. GrantEyeglasses for improved visual contrast using hetero-chromic light filtration
US7931369Jul 13, 2007Apr 26, 2011David Andrew HarrisTinted lens and method of making same
US8414127Mar 31, 2011Apr 9, 2013Chromagen Vision LlcMethod of making and prescribing tinted lenses
US8820923Aug 2, 2012Sep 2, 2014Nitto Denko CorporationOptical element for correcting color blindness
US8845095Aug 2, 2012Sep 30, 2014Nitto Denko CorporationOptical element for correcting color blindness
US8931930Jan 29, 2013Jan 13, 2015Nitto Denko CorporationOptical element for correcting color blindness
US8939576Aug 2, 2012Jan 27, 2015Nitto Denko CorporationOptical element for correcting color blindness
US8963104Aug 2, 2012Feb 24, 2015Nitto Denko CorporationOptical element for correcting color blindness
US8977051 *Mar 15, 2013Mar 10, 2015Show Chwan Memorial HospitalImage enhancement method for improving color perception of colorblind viewers
US9022562Aug 2, 2012May 5, 2015Nitto Denko CorporationOptical element for correcting color blindness
US9028064Jun 25, 2012May 12, 2015Chromagen Vision LlcMethod of making and prescribing tinted lenses
US9443488Jul 20, 2015Sep 13, 2016Digital Vision Enhancement IncImage transforming vision enhancement device
US20080137030 *Nov 2, 2007Jun 12, 2008Hoffman William COptical devices with reduced chromatic aberration
US20090015786 *Jul 13, 2007Jan 15, 2009David Andrew HarrisTinted lens and method of making same
US20110176105 *Mar 31, 2011Jul 21, 2011Chromagen Vision LlcMethod of making and prescribing tinted lenses
US20140270516 *Mar 15, 2013Sep 18, 2014Show Chwan Memorial HospitalImage enhancement method for improving color perception of colorblind viewers
EP0204347A2 *Jun 6, 1986Dec 10, 1986Firma Carl ZeissContact lens coloured in certain areas
EP0204347A3 *Jun 6, 1986Sep 21, 1988Firma Carl ZeissContact lens coloured in certain areas
EP2506064A2Mar 28, 2012Oct 3, 2012ChromaGen Vision LLCMethod of making and prescribing tinted lenses
WO1992012451A1 *Jan 3, 1991Jul 23, 1992X-Chrom CorporationContact lens for correction of color blindness
WO1998025173A1 *Nov 27, 1997Jun 11, 1998David Andrew HarrisImproving colour discrimination
WO2014107591A1Jan 3, 2014Jul 10, 2014Nitto Denko CorporationMethod for forming an oxide coated substrate
Classifications
U.S. Classification351/246, 351/41, 351/242, 351/44, 351/159.3
International ClassificationG02C7/10, G02C7/04
Cooperative ClassificationG02C7/04, G02C7/10, G02C2202/10
European ClassificationG02C7/04, G02C7/10
Legal Events
DateCodeEventDescription
Mar 15, 1983PSPatent suit(s) filed