CSIO develops affordable, high-power lens for visually impaired

The Central Scientific Instruments Organisation (CSIO), Chandigarh, has developed high-powered aspheric lens-based spectacles, known as Low-Vision Aids (LVA), to provide an affordable assistive device for patients suffering from severe or functional low vision (FLV).

These lenses have been developed with different power combinations, such as +12D, +16D, +20D, and +26D, and can be customised for other power requirements depending on the patient’s needs and extent of vision loss.

Compared to conventional spherical glass-based lenses, these aspheric LVAs are 60 per cent lighter and more powerful, offering better optical performance in terms of reduced aberrations and higher image quality.

According to scientists at CSIO, “These lenses are like using a magnifying glass for people with extremely low vision.” However, conventional lenses of such power would be extremely large and bulky, making LVAs a convenient option, especially for children.

The LVAs were launched at a function chaired by the President of India, Droupadi Murmu, during the National Awards for Empowering Divyangjans 2024, in New Delhi.

Scientists associated with the project explained that FLV is defined as impaired visual function that persists despite treatment or refractive correction. It can also be described as a visual acuity of less than 6/18 or a visual field less than 10 degrees from fixation.

According to estimates, the prevalence of FLV in India is estimated to be 1.05 per cent, affecting roughly 1.4 crore people.

These LVAs have been fabricated using the single-point diamond turning process, an ultra-precision machining technique used for fabrication of aspheric lenses. User trials were carried out in collaboration with the Artificial Limbs Manufacturing Corporation of India, Kanpur, and the National Institute for the Empowerment of Persons with Visual Disabilities, Dehradun.

Plans are underway to scale up the manufacturing of these LVAs using moulding techniques, enabling rapid production and faster deployment among the affected population. The pricing for these lenses is also being worked out.