My character has a prosthetic, or technically you could say a bionic or cybernetic, left eye. For one reason or another, the replacement eye couldn’t be connected directly to the optic nerve. Instead, all of the visual system for the left eye has to be replaced (optic nerve, optic tract and such) with wiring or something similar.

How would this surgery procedure go and how would they connect these new parts of the visual system to the brain to allow the new eye to function as well as the original?

The answer should be purely ‘mechanical’ in nature, as in none of this future ‘biotech’ or things were organic components can just be manipulated so it ‘just works.’

Edit: Future technology is fine, necessary even. The future tech i'm asking to be not included is things like fully grown organic replacements, nano-technology, or bio-engineering of the human itself.

  • 2
    $\begingroup$ When, how much future tech do you want thrown at this because we couldn't really do it today? $\endgroup$
    – Ash
    Jun 10, 2019 at 16:47
  • $\begingroup$ I'll answer, but need to know some basics first: What level of detail are you looking for? Also, what is the "starting point" of the narrative? That is, are we replacing a healthy eye or has your character just been mangled and has bits of shattered bone and shredded eye tissue dangling off the side of her face? Lastly, how future is future? In other words, what's the timeframe? $\endgroup$
    – elemtilas
    Jun 11, 2019 at 17:19

3 Answers 3


Transcranial cortical stimulation.

Transcranial magnetic stimulation of the visual cortex induces somatotopically organized qualia in blind subjects

Transcranial magnetic stimulation uses external magnetic fields to induce currents in specified areas of the brain. The visual cortex in the occipital lobe is responsible for handling inputs from the eye. Stimulation of the occipital lobe with magnetic fields can produce the perception of a light spot; this as of 1991.

In your near future, magnetic brain stimulation is much more precise. Your cyborg has an eyepiece which translates light stimuli directly into magnetic fields and delivers these to the brain with a Lobot-like overlying magnet. Nothing breaks the skin.


Okay you're looking at some form of wire implanted using a 3D Floroscope. You're going to need to throw some future-tech jargon around to justify wiring that can interface with the human nervous system, they'll need to be nanoscale and have "synapto-scale chemo-responsive" ends, in short they'll need to fake it as nerve endings, with all the chemical receptors and output capability that that entails (they can synthesis neuro transmitters from material supplied by the blood stream using bio-identical synthesis pathways or they may need regular top ups of precursor chemicals injected into their eye) and their placement will need to be accurate to the nanometre for signal transmission to be successful. Additionally you will need "bio-encoding" i.e. a computer chip that turns digital video into analog biochemical signals that your synapses can run with. If you can hack the nerve-body interface then all you really need is a small hi-spec camera, most modern cell phones have built-ins that have high enough pixel counts to do the job.


Microelectrode arrays

With tiny enough electrodes you can read and write electrical signals to/from individual neurons. The actual technology for doing this is undergoing rapid change so it would be best to be vague on this in your story. Implantation of microwires is a promising approach, especially since similar implants have been shown to be stable in monkeys for 7+ years. There's also neural smart dust, where one has a sprinkling of wirelessly powered and communicating electrodes. For replacing the optic tract, we can do something similiar to what is done with hippocampal prostheses and emulate the transfer function of the optical tract using computers or custom hardware. If worst comes to worst, there's always direct stimulation of the visual cortex. Medical trials are being carried out on this right now. The resolution isn't very good, but as the bandwidth of microelectrode arrays improves, resolution should too.


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