This week you can read about how I got on with a virtual reality headset able to simulate vision through a variety of lenses either in the real world or a simulated ‘virtual’ world. I think we are just seeing the first of what will be many innovations in the use of such technology in eye care.
The brain is able to analyse electrical input from an external stimulus, combine and contrast with other incoming signals, interweave the signal pattern with existing networks representing previous experiences, and produce a perception or conscious awareness. Anything that can produce an incoming signal is able therefore to influence this perception.
Virtual reality offers a way of changing the stimulus to which receptors respond and so should, in theory, be perfectly able to change a perception completely. The better the simulation of a real-life environment, the more likely the brain can tap into existing memory to create a new reality.
So there are now several options for creating perception. Virtual reality inputs can bypass existing stimuli. This might be useful in creating a simulated reality and is already providing help in, for example, pain relief techniques where a patient is so focused on negotiating a simulated real world that their chronic pain signals are dampened.
There may also be options to provide signals from an existing blind field, such as after a stroke, to a functional field area to re-establish a full field. Another option is to replace the damaged receptors themselves, either artificially, as with some of the retinal and cortical implants currently under trial, or with newly generated healthy cells. Cochlear implants are a good example of how an artificial transducer can produce signals which pass to the brain when the body’s own sensory receptors malfunction. If we can survive our innate urge to self-destruct, the future for sight loss has never looked better.