Visual Impairment

We are often blind to the problems of the visually impaired

338 million people suffer from blindness and serious visual impairment

Blindness and serious visual impairment are a global problem. World-wide, there are 43 million people who are blind and a further 295 million who suffer from serious visual impairment.

Population growth, aging and diseases like diabetes are contributing to a global increase.  By 2050 there are expect to be over 535 million people suffering from blindness and serious visual impairment.

The social and economic cost of this are significant.


Bourne R, Steinmetz J, Flaxman S, et al., Trends in prevalence of blindness and distance and near vision impairment over 30 years: an analysis for the Global Burden of Disease Study. Lancet Glob Health. 2020. Accessed via the IAPB Vision Atlas (

Modern life is fraught with challenges for the functionally blind

For the individual a lack of sight impacts every aspect of their life. Modern life has only increased the challenges that a lack of sight brings.  The freedom-of-mobility gap between visually-abled and visually-impaired is growing ever larger, putting a significant part of society at a huge disadvantage from a social, economic and technological perspective.

Existing solutions for the functionally blind are inadequate

Despite the advances of the last decades, technology has yet to deliver for the functionally blind.  There is a need for effective Assistive Technologies that enable them to independently move safely indoors and outdoors, perceive the surrounding environment and interact with people.

There is a particularly need for new technologies that can aid independent mobility.  Numerous attempts have been made to enhance the traditional cane with ultrasound and other detectors. They have had limited success because they interrupt a blind person’s most import sense – their hearing. 

It remains that the most common aids are still specially trained dogs and the traditional white cane, invented by James Bigg in 1921. For the vast majority of the functionally blind, they rely on sighted assistants.

Telehaptics’ technology aims to change this.

There is no universal definition of visual impairment

Visual impairment is generally determined by measuring the better-seeing eye for the best distance vision while using optimal refraction correction (eye glasses, contact lenses, laser surgery etc.).

Most studies measure visual acuity at a distance of 6 metres (20 feet) using the standardised Snellen Eye Chart.  Common definitions of serious visual impairment would be 6/18 to 6/60 (moderate VI), 6/60 or worse (severe VI).  Blindness is defined by the World Health Organisation as 3/60 or worse.

The legal definitions in each country differ for determining eligibility for vocational training, rehabilitation, schooling, disability benefits, low vision devices, and tax exemption programmes. In the US, these are defined as 6/60 or worse.  In the UK, suffers can be recognised as either Severely Visually Impaired or Registered Blind.