AFFORDABLE LOW VISION DEVICES WITH PLASTIC ASPHERIC LENSES.

What is Low Vision?

Low Vision indicates a vision of less than 6/18 but more than 3/60 or field of vision reduced to 20 deg. or less. People having Low Vision are termed as `partially blind’ and their number in India is estimated to be 45 million as per the ICMR (Indian Council of Medical Research) survey (1991), with majority of these LVPs living under poverty line.  

If such patients are not treated timely, low vision may eventually lead to blindness. People with low vision feel visually handicapped thereby having difficulty either in recognizing objects at a distance or at a close range.  

Such type of visual impairment, many a times, can not be corrected by medical or surgical procedures nor with conventional eye glasses.

What are Low Vision Aids?

For in-correctable causes of vision loss, Low Vision Aids play a significant role. The goal of Low-Vision Care is to provide a technological intervention at an affordable cost for the visually impaired patient to make maximum use of residual sight by employing suitable Low-Vision Aids (LVAs). Various types of Low-Vision Aids are popularly used globally by LVPs. These LVAs can be mainly classified into spectacle and non-spectacle types.  

The function of all optically designed `Low Vision Aids’ is to provide an enlarged retinal stimulus pattern that calls into play additional nerve receptacle.

Magnifying glasses, Telescopic lenses, Visual field expanders, Night-Vision Pocket-scopes, closed circuit television with CCD are some of the devices used as low vision aids.  Spherical glass magnifiers of high dioptric powers cause distortion of the reading material at the periphery of the lens, thereby reducing the field of vision. Such types of magnifiers, if corrected for the distortion will be of multi-element nature and hence will become quite heavier than their single element counterpart.  Aspheric plastic magnifiers can be designed with better peripheral aberration correction. Evidently plastic lenses are lighter than their glass counterparts. Compared to Low-Vision Aids using spherical components, those employing aspheric plastic components offer light-weight, better correction at the periphery. These Low-Vision Aids when made in large volumes, will be very cost-effective and will certainly meet the long-felt requirements of visually handicapped persons.

What did OPTICA do?

Optics & Allied Engg. Pvt. Ltd., Bengaluru (OPTICA) has partnered with a DRDO (Defense Research & Development Organization) laboratory to develop the Aspheric Plastic Lens based Low Vision Aids for the first time in India.

Subsequently, OPTICA has pioneered in India, (both in public and private sectors) the large-scale production of Affordable Vision Aids for Magnifiers and Spectacles using Plastic Aspheric Lenses for various refractive requirements (16D, 20D, 24D, 28D).  

LOW VISION AIDS DEVELOPED @ OPTICA – FEATURES

• Plastic Aspheric Lenses
• Light Weight
• Affordable Cost
• High Field of View
• No peripheral Aberrations
• Dual Configuration Devices (Magnifiers for Reading & Spectacle Mounted)
• Available Refractive Powers +!6D, +20D, +24D, +28D
• Indigenous Technology Development

LOW VISION AID DEVELOPEMNT – SKILLS DEPLOYED

In this effort, OPTICA has deployed its expertise in novel optical and mechanical designs employing plastic aspheric; manufacturing of moulds and replication of plastic aspheric as per specifications, scratch-resistant coating, iterative testing and finally exhaustive user

trials for the prototypes thus developed.  

This exercise involves the expertise in the multiple areas of Optical Design, Opto-Mechanical Design, Precision Die Manufacturing, Injection Molding, thus fulfilling the scope of the development in terms of light-weight, better performance and low-cost.

DEFENCE TECHNOLOGY SPINN-OFF AWARD TO OPTICA

For this effort OPTICA was awarded the DEFENCE TECHNOLOGY SPINN-OFF AWARD (Ministry of Defense) by the then Honorable Prime Minister of India, Bharata Ratna Shri Atal Bihari Bajpayee on 11^th May, 2001.