Anamorphic lens system increasing the field of view for the visually handicapped

11/26/85 OF 4,555*164

United States Patent m

Feinbloom

[54] ANAMORPHIC LENS SYSTEM

INCREASING THE FIELD OF VIEW FOR
THE VISUALLY HANDICAPPED

[75] Inventor: William Feinbloom, Highland, N.Y.

[73] Assignee: Designs for Vision, Inc., New York, N.Y.

[21] Appl. No.: 471,765
[22] Filed: Mar. 3, 1983

[51] Int. CU G02B 27/02; G02B 13/00

[52] U.S. Q 350/420; 351/41

[58] Field of Search 350/420, 433, 469, 434,

350/145, 437, 440

[56] References Cited

U.S. PATENT DOCUMENTS

3,002,427 10/1961 Schafter et al 350/420

3,511,557 5/1970 Lindstedt et al 350/420

3,822,932 7/1974 Humphrey 350/420

4,364,645 12/1982 Feinbloom 351/204

[ii] Patent Number: 4,555,164
[45] Date of Patent: Nov. 26, 1985

Primary Examiner—John K. Corbin
Assistant Examiner—Rebecca D. Gass
Attorney, Agent, or Firm—Arthur L. Plevy

[57] ABSTRACT

There is disclosed an anamorphic lens system for increasing the field of view for patients or persons having tunnel vision. The lens assembly consists of a plano-concave cylindrical lens separated from a plano-convex cylindrical lens. The lens system is an anamorphic lens system which minifies in one meridian or axis such as the X axis while keeping objects at the same size in the other meridian such as the Y axis. In utilizing the system, a handicapped patient is now able to maintain almost their original visual acuity in the vertical plane while the system produces minification in the horizontal plane. By using such a technique, the patient retains almost full visual acuity, experiences a substantial increase in his field of vision, and furthermore, does not lose the ability to judge depth.

13 Claims, 5 Drawing Figures

4,555,

ANAMORPHIC LENS SYSTEM INCREASING THE FIELD OF VIEW FOR THE VISUALLY HANDICAPPED

5

BACKGROUND OF INVENTION

This invention relates to a lens system for improving the field of view of the visually handicapped and more particularly to an anamorphic lens system.

There are patients who exhibit visual handicaps that manifest themselves in eye conditions that produce tunnel vision. Such patients usually have good central vision (within the narrow confines of the tunnel vision) and are limited to fields of view of about 5 to 15 degrees. 15 Accordingly, such persons virtually have no peripheral vision. Such a condition which manifests itself in tunnel vision is found in cases of Retinitis Pigmentosa.

Retinitis Pigmentosa is an inherited disease which is usually first observed in patients between the ages of 8 20 to 14 years. As these patients become older, the peripheral field of view, generally grows smaller and smaller. Although Retinitis Pigmentosa is a major cause of tunnel vision, there are other diseases that also produce a loss of the peripheral field. In any event, the afflicted 25 person who may have a typical central field of 5, 10, or 15 degrees is still able to walk around and to perform other tasks by combining their eye movement with head movement to enable them to scan the surrounding environment. However, at any instant, they only see a very 30 limited field and must mentally combine these many limited fields to perceive some semblance of real space.

Essentially, the ability of the brain to correlate such information enables them to function with rather limited field of view. 35

For normal eyes the average field of vision is about 135 degrees in each eye and binocularly such persons have a 180 degree field of vision. This, of course, is inherent with peripheral vision.

In contrast patients afflicted with Retinitis Pigmen- 40 tosa may have a field of view as little as 5 degrees and hence must constantly scan the scene in front of them by eye and head movement to avoid bumping into people or objects.

The condition of tunnel vision as manifested by many 45 of these afflictions has been known since ancient times and all attempts proposed to provide a practical solution to increase this field have failed for one reason or another.

A particular approach which was experimented with 50 in the prior art was to prescribe a reverse telescopic spectacle to increase the field of vision. This approach has not worked for two main reasons.

First, the regular reverse telescopic spectacle does not minify space and allows the patient to take in a 55 larger field of view, but at the same time, it also reduces the patient's visual acuity. That is, a reverse telescope will provide minification in both the vertical and horizontal meridians or planes and therefore reduces such objects in size, thus reduces his amount of vision or 60 visual acuity.

For example, if the reverse telescope minifies by a factor of — 2.0X, then the percentage of vision or visual acuity will be reduced by two times or cut in half.

The second objection results because of the reduction 65 in size of the image, the patient experiences a misjudgement of position because the object in space appears to be twice as far away in the above example.

164

2

These two factors are inherent characteristics of all reversed telescopic systems which normally employ spherical lenses.

Basically, it is an object of this invention to maintain one meridian at a constant size by the use of a special telescopic spectacle. It has been determined experimentally that in offering such a system, the acuity of the patient is preserved while further allowing the patient to make accurate judgements in distances. By use of this invention the patient may walk up steps, work in a factory or at home and in general will be able to perform normal tasks with good visual acuity and distance judgement.

In describing the invention, it is designated as an anamorphic lens system and constitutes lenses having a different power vertically and a different power horizontally. In this manner the lens system produces minification in the horizontal meridian only, while leaving the vertical meridian with zero effect.

This minification of the horizontal meridian only provides the patient with a wider field of view by fitting, for example, 10 degrees of real space into the patient's own 5 degree field. Thus, the horizontal field of view for the patient is increased by the same percentage as the power of the anamorphic system, according to the minification, as will be explained.

The anamorphic lens assembly is essentially a reverse cylindrical telescope that minifies in one meridian or axis as the horizontal, while maintaining the image of the vertical meridian at the same size.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT

A lens assembly for increasing the field of vision of a user having a visual handicap indicative of a condition designated as tunnel vision, said lens assembly operative to increase the field of view by minifying optically in one plane, while substantially not altering the object size in another plane transverse to said one plane, comprising a first cylindrical lens assembly positioned at a given distance from a second cylindrical lens assembly, with said first and second lens assemblies positioned near the eye of said user to enable said user to perceive with normal acuity in said one plane and with a minification of vision in said another plane with said minification proportional to the increase in user's field of view.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic plan view of an anamorphic lens assembly according to this invention.

FIG. 2 is a cross sectional view of a telescopic housing for the anamorphic lens assembly.

FIG. 3 is a front plan view of a trial frame employed in testing patients for this invention.

FIG. 4 is a top plan view of the trial frame.

FIG. 5 is a side elevational view of the trial frame.

DETAILED DESCRIPTION OF THE FIGURES

Referring to FIG. 1, there is shown a schematic diagram of an anamorphic lens system according to this invention. Anamorphic lenses are usually made of all precision piano-cylindrical surfaces. In the system to be described, the lenses are depicted as piano on one surface and having plano-concave or plano-convex cylindrical radii on the other surface.

The axis of the cylinder surface or lens is that meridian of zero power or infinite radius. This axis is not the optic axis of the system. The system to be described