Brain implants and artificial vision; what would you do to see again?
words by Charlie Ellis, Staff Writer
If you were to go blind one day, what would you do to be able to ‘see’ again? Unfortunately, this was a question that science-teacher Berna Gomez had to face due to an undiagnosed toxic optic neuropathy (TON).
TON occurs due to exposure to a neuro-poisonous toxic substance, which is often ingested within food/drink and/or particular prescribed medications. There are many examples of these substances, some of which include: methanol, or drugs such as isoniazid and disulfiram used for tuberculosis and chronic alcoholism respectively.
In TON, the ingested toxic substances lead to damage of the optic nerve, which is vital for visual processing. This is because the optic nerve is the main ‘connection’ between the retina and our visual cortex (brain region involved in integration of visual signals). Therefore, due to the optic nerve damage TON patients often present symptomatically with gradual visual decline (impaired vision), and then in rare cases — complete blindness.
In the case of Gomez, she experienced an aggressive case of TON, which led to her becoming functionally blind at the age of 42, prematurely ending her career as a science teacher. For many years, she continued to live as a blind woman in Elche, Spain. Until, in 2018, she bravely decided to volunteer to be a part of a medical trial, which involved complex neurosurgery and a small brain implant.
This medical trial was led by Richard A. Normann, PhD, and attempted to create artificial vision using a prosthesis that was electrically wired into Gomez’s brain, which acted by bypassing the eye and optic nerve, instead activating the visual cortex neurons. The first step of this trial involved a Utah Electrode Array (UTA), a specialised set of very small electrodes, created by Normann, being implanted into Gomez’s visual cortex to stimulate and record the electrical activity of certain visual cortex neurons. Vitally, the implant caused no damage to surrounding neurons or any complications in surgery that other implants have caused in the past.
Throughout the trial, Gomez had to wear specially designed glasses which contained a miniature camera. The video collected by this camera was converted by specialised software into data the UTA could ‘understand’. Therefore, when the UTA received this converted data, it could stimulate certain visual cortex neurons, producing phosphenes, which Gomez could ‘see’ as white points of light, in turn, creating an image. This set-up of the UTA and specialised glasses was dubbed the Moran|Cortivis Prosthesis.
After approximately two months of training, the Moran|Cortivis Prosthesis allowed Gomez to be able to identify lines, shapes and some simple letters (such as I, L, C and V) for the first time since she went completely blind. This was due to the differences between artificial (evoked by researchers directly to the UTA without the glasses) and ‘real’ (evoked by real images using the glasses) stimulation transmitted to particular visual cortex neurons creating an ‘image’. After six months of trialling this equipment, the implant was removed, which led to Gomez going blind again. Speaking in a statement she said; “I know I am blind, that I will always be blind… But I felt like I could do something to help people in the future…” Due to her admirable dedication and work on the project, Gomez is listed as a co-author of the published research paper.
Admittedly, whilst we are a long way off developing implants that can reliably restore vision completely, this research is a huge step in the right direction as it demonstrates that these prostheses can be safe and effective, albeit for 6 months only in a single trial. In the future, this team of researchers led by Normann hope to use more sophisticated equipment to produce even more complex visual images, with the eventual aim to effectively ‘cure’ blindness.