WO2018008043A1

WO2018008043A1 - Vision aid device for improving vision of patients with retinal and optic nerve disorders

Info

Publication number: WO2018008043A1
Application number: PCT/IN2017/050275
Authority: WO
Inventors: Palanivelu Mahesh SHANMUGAM
Original assignee: Sri Kanchi Kamakoti Medical Trust
Priority date: 2016-07-06
Filing date: 2017-07-06
Publication date: 2018-01-11

Abstract

The present invention provides for vision aid devices for improving vision of patients with retinal and optic nerve disorders. The vision aid devices are augmented with polarizing filter(s) to filter out the horizontally polarized waves of light to reduce the glare and hence increasing the visibility. The use of polarizing filter in the vision aid devices improves distance and near vision in patients with retinal and optic nerve diseases even in patients having undergone the best possible medical and surgical treatment and the patient still experiencing poor vision. The present invention solves the problem with minimum amount of modification in the existing vision aid devices making its application easy and cost effective.

Description

TITLE OF THE INVENTION

Vision aid device for improving vision of patients with retinal and optic nerve disorders

FIELD OF THE INVENTION

The present invention relates to the vision aiding/improving devices, more specifically it relates to the use of polarized filters in vision aid devices for improving vision of patients suffering with retinal and optic nerve disorders.

BACKGROUND OF THE INVENTION Optic nerve disorders are characterized by reduced visual acuity and colour vision, a relative afferent pupillary defect (RAPD), visual field defects and changes in the optic disc appearance.

Low vision is a condition caused most often by diseases of the optic nerve and retina resulting in reduced level of vision that cannot be fully corrected with conventional glasses. In terms of visual acuity, low vision is when vision is less than 6/24 in the better eye. The low vision interferes with the performance of daily activities, such as recognizing objects at a distance, differentiating colors, seeing up close and driving etc.

To rectify the problem of low vision the patients are given magnifying glasses and increased illumination to help them see better. These glasses are thick and allow one to see only at close quarters. Other type of vision aids include communication aids such as computer software and various other technological devices. However, most low vision aids are useful for near vision not for distance vision. In most of the conditions the low vision cannot be corrected with regular glasses, contact lenses, medicine, or surgery. There are some patients who have decreased vision but not low vision. The patients with decreased vision but not low vision will have better than 6/24 vision but not normal vision. Such patients do not tolerate low vision aids as their vision is sub-normal but not so much that they have to depend on low vision aids.

The sub-normal vision can be defined as any visual defect which in the normal course of refraction cannot be suitably aided so as to permit the individual to perform visual tasks necessary in pursuing a satisfactory manner of life (Bernard S. Abrams O.D., The Australasian Journal of Optometry, Volume 38, Issue 2, pages 57-64, February 1955)

Wherefore, there is a requirement of vision aid or assistance which could effectively help the patients with retinal and optic nerve disorders such as subnormal and low vision thereby improving their vision.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the known vision aid devices, the present invention provides an improved vision and overcomes the abovementioned disadvantages and drawbacks.

In one aspect of the invention, a vision aid device for improving vision of patients with retinal and optic nerve disorders is provided. The vision aid device includes one or more lenses to receive incident light, and one or more vertical polarizing filters affixed to the one or more lens. The vertical polarizing filters cut off the horizontally polarized waves of incident light reaching to eyes of the patient. The one or more vertical polarizing filters are adapted to rotate in front of eyes in order to obtain the best position as per orientation of the nerve fiber layer of the patient. The one or more vertical polarizing filters reduce incident light intensity by 5% to 80%.

In another aspect of the present invention, the one or more vertical polarizing filters adapted to be used in absence of the one or more lenses.

Other features of the embodiments will be apparent from the accompanying drawings and from the detailed description that follows. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawing in which:

Figure 1 illustrates the use of a vision aid device to filter out the polarized light, according to an embodiment of the invention.

Although specific features of the present invention are shown in the drawing. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for vision aid device for improving vision of patients with retinal optic nerve disorders and other eye disorders.

The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments. The present invention can be modified in various forms. Thus, the embodiments of the present invention are only provided to explain more clearly the present invention to the ordinarily skilled in the art of the present invention. In the accompanying drawings, like reference numerals are used to indicate like components.

The specification may refer to "an", "one" or "some" embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/or "comprising" when used in this specification, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations and arrangements of one or more of the associated listed items. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In the present invention, the vision aid devices are augmented with one or more polarizing filters to cut off the horizontally polarized waves of light. The vision aid devices may include eyeglasses/ spectacles and low vision aids. Some examples of low vision aids including, but not limited to, stand and handheld magnifiers, strong magnifying reading glasses, loupes (Clip-on), and small telescopes. With help of the present vision aid device the visually impaired may have the opportunity of leading near normal lives at study and work.

The visually impaired, need a higher level of luminous intensity since their vision is below par. Therefore, an easy solution to this would be increasing the luminosity. However, exposure of such patients to higher intensity of light is accompanied by the associated problem of 'glare'. With the illumination levels being higher, the glare component also gets aggravated. It is a well- established theory that light being reflected from a plane surface tends to get many modes of its vibration from the unpolarized source and gets aligned into the horizontal orientation (the light waves realigns into predominately horizontal transverse waves). Usually the natural illuminating light also get scattered by atmospheric particles and hence partially polarized. These horizontally polarized light waves lead to perceived images of glare and blurriness that is extremely uncomfortable not only to visually impaired but also people with normal vision. This had been a deterrent in effective treatment of the patients with subnormal and low vision. In order to make the vision aid devices for the patients with subnormal and low vision, the present invention augments the eyeglasses or other low vision aids with the one or more polarizing filters to cut off the horizontally polarized waves of light. In an embodiment of the present invention, the vertical one or more polarizing filters are used. This helps in cutting off of the horizontally polarized waves reduces the glare and thereby increases the visibility. For this purpose, suitable vertically polarizing filters are designed which could filter out the horizontally polarized waves.

In another embodiment of the present invention, circular polarizer vertically polarizing filters are used. However, linear polarizer also works but in most cases, it was found inferior to the circular polarizer. The circular polarizer can cut all the divergent rays and allow a particular segment of the polarized light waves to reach the retina and thereby enhancing patients' vision. Each patient has different orientation of the nerve fiber layer, therefore, the circular polarizer is rotated in front of the eyes to achieve adjustment to orientation of the nerve fiber layer so as to obtain the best position for enhancing/improving visibility of the patient.

The one or more vertical polarizing filters used herein reduce incident light intensity by 5% to 80%. In an embodiment of the present invention, a standard filter with 65% filtering effect is used. The combination of the percentage of light blocked / reflected plays a crucial role here. Therefore, the polarizing filters used in the vision aid device are fine-tuned to find the appropriate combination for percentage light blocked / reflected for imparting better clarity in vision.

Figure 1 illustrates an example of the vision aid device, where an eyeglass is augmented with the circular polarizer vertical polarizing filters. The light (104) coming from a high illumination source (102) after getting reflected from a reflective surface (106) gets horizontally polarized (108) adding glare to the light. The horizontally polarized light (108) is filtered out with the help of the vision aid device augmented with the vertically polarized filter (1 10). Therefore, the light reaching to the eyes of patient has less glare. The reduction in glare thereby enhances vision of the patients who are suffering with the subnormal and low vision.

In yet another embodiment of the present invention, depending on the user/patient requirement the polarized filer/lens can be used alone or with other low vision aids to improve the vision of patients. Study of effect of lighting on efficacy of the present vision aid devices is conducted. It was found that patients using the vision aid devices performed best under Yellow lights (Tungsten Bulbs), and sunlight. This improvement significantly decreased when tests were performed under CFL or LED bulbs which are white in colour. Testing under tube light was not done as this requires focused light which cannot be achieved with tube lights. Focused light at a distance of 150 cm and angled at approximately 45% between the subject and reading material was used during the tests. The successful tests were performed on the patients with various Optic nerve and macular lesions, Optic atrophy, Age related macular degeneration, Cone Rod dystrophy, Macular scar, Stargarth's disease, and Burnt out diabetic maculopathy.

The use of polarizing filter in the vision aid devices improves distance and near vision in patients with retinal and optic nerve diseases even in patients having undergone the best possible medical and surgical treatment and still experiencing poor vision.

Patients with a minimal V/A of better than 20/200 or 6/60 were the ones most benefitted from the vision aid devices. However, patients with much lower V/A, though noted improvement but was noted really unquantifiable. On an average 80% of 228 odd patients tested had shown great improvement in V/A and on an average had 4 line improvement more so for near V/A. Distance V/A also improved but not in par with the near V/A.

The present invention provides an effective solution to the problem of the low vision condition, which cannot be corrected with regular glasses, contact lenses, medicine, or surgery. The present invention solves the problem with minimum amount of modification in the existing vision aid devices making its application easy and cost effective.

The one or more vertical polarizing filters fitted in vision aid devices, enable the wearer to carry out intricate jobs like reading-writing or vocational jobs like assembly, knitting, stitching etc. and thus provide them livelihood related occupations.

Claims

We Claim:

1 . A vision aid device for improving vision of patients with retinal and optic nerve disorders, comprising: the vision aid device having one or more lenses to receive incident light; and one or more vertical polarizing filters affixed to the one or more lens, thereby cutting off the horizontally polarized waves of incident light reaching to eyes of the patient, wherein the one or more vertical polarizing filters adapted to rotate in front of eyes in order to obtain the best position as per orientation of the nerve fiber layer of the patient, and wherein the one or more vertical polarizing filters reduce incident light intensity by 5% to 80%.

2. The vision aid device as claimed in claim 1 , wherein the one or more vertical polarizing filters are circular polarizer having capability of cutting all divergent rays and allowing a particular segment of the polarized light waves to reach retina.

3. The vision aid device as claimed in claim 1 , wherein the one or more vertical polarizing filters adapted to be used in absence of the one or more lenses.