Ultraviolet and Infrared vision for the blind « Technology Tales

Technological extensions of the body to increase quality of life are forever evolving, and the latest dimension of human enhancement with 'retinal prosthetics' could allow the blind to see.

An article from the UK Guardian by Dr Patrick Degenaar, explores the unique possibilities for a new, modified – and even enhanced – form of vision.

"The purpose of retinal prosthetics is to restore sight to patients who have a degenerative condition called retinitis pigmentosa, which affects one in 3,500 people. In the condition, the retina's light-sensing cells – rods and cones – become inactive and eventually die. Symptoms start with night blindness and worsening tunnel vision, but eventually there is a total loss of sight.

Optogenetics, an exciting new gene therapy technique… last year was hailed as Method of the Year by the journal Nature. Invented in the lab of Ernst Bambergat the Max Planck Institute in Frankfurt eight years ago, the technique uses gene therapy to sensitise nerve cells to particular colours of light. Intense pulses of this wavelength of light make the photosensitised nerve cells fire. (Neurologists call each firing of a nerve an "action potential" – the currency of information in the nervous system.)

So in optogenetic retinal prosthetics, rather than performing highly complex surgery to implant electrodes into a patient's retina, a solution of a special virus would simply be injected to introduce new genes into the nerve cells. The patient would then wear a headset that records and interprets the visual scene and sends coded pulses of light to the retina. As a single pulse of light can generate a single action potential, the information encoded from the visual scene can be much more in tune with the neural song expected by the visual cortex."

"Even if resolution is low, the prosthesis could allow users to experience the visual world in wavelengths beyond those perceptible to normal-sighted humans. For example the eye absorbs ultraviolet light before it reaches the retina, and nature finds it difficult to make infrared light receptors. Such constraints do not affect modern camera technology.

This "multi-spectral imaging" could be used for purely pragmatic purposes, such as telling at a glance whether an object is too hot to touch. Alternatively, it could create a certain visual poetry by allowing us to experience a flower in all its ultraviolet glory – as seen by honey bees.

By exploring these possibilities in our research, it may be possible to improve the experience of the patients who will eventually wear these prostheses, allowing them to enjoy some of the benefits of the new field of augmented reality."