Batteries can be made quite small today, and batteries can be recharged wirelessly by magnetic resonance. So feasibly, the battery could be implanted in the temple near the eye and be recharged by putting a charger against the temple.



It might also be possible to charge the eye simply with the light that enters it. If the battery is running low, just stare at the sun for a few minutes.

Although I like the classic cyberpunk concept that states that nanomachines build a small turbine generator in one of your biggest veins (like the inferior vena cava), I understand you want something built into the eye...

What about an enzymatic generator? It extracts energy from the sugars and fats of your body. You can make it tap into the bloodstream, and wouldn't need a battery (although you probably want to combine with one so if you start using the advanced functions it won't leave your user craving junk food or worse, in a hypoglycemic coma).

SIDENOTE: The enzymatic generators DO exist. It's something the army has been researching because theoretically they can be fed anything organic, so can be very useful. Of course the army ones tend to be on the big size, but can be made today as small as an AA battery, if fueled by pure sugar. They have organic compounds (the enzymes that break down the sugars and fats) that degrade over time (or worse, can overgrow), so your cyberenhanced user will need to do regular maintenance (maybe once or twice a year) to keep the battery enzyme levels on check.

Owner's blood! + Light + Blood additives

Because:

• It does not requires much space, which you don't have.


• It is abundant in the body.


• It does not interferes with mechanisms of vision.

Additionally:

• Photovoltaic panel.




• Blood additives that makes blood more efficient.

See also:

• https://en.wikipedia.org/wiki/Biobattery




• https://www.insidescience.org/news/could-pacemakers-be-powered-sugar

Try using the same thing which powers a cybernetic ear, or what boring people call "a hearing aid", which is typically a tiny lithium battery.

Depending on your power draw, it may be possible to run your implant entirely from the patient's own body heat. If it's particularly high you may still need to replace the battery, but having it constantly recharge will extend its life, reducing the number of battery replacement surgeries required.

There's some advanced tech today that can run on body heat, but as this is sci-fi, you can take that much further and run with that idea.

So ideally instead of building a storage system that has to run infinitely or be replaced, you'd have it get energy from the body's own systems. Maybe from the beating of the heart, or glucose in the blood stream, or even oxygen in the blood stream. I mean you've got a power source right there in the human body, so why not use it.

But some of the functions are far beyond what regular eyes do, so I would think those functions would take extra energy. In that case, you'd want storage. Basically a tiny re-chargeable battery that temporarily stores energy (like a solar battery) but can't hold a charge for very long and constantly has to be renewed.

Either it stores energy while you sleep (in which case the extra functions are limited in a per-day capacity) or it stores excess energy as you go, in which case the capacity to use the extra functions will "recharge" in a few minutes/hours or whatever.

I'd suggest a small thermogalvinic cell it uses low heat differential to generate electric current directly. You just siphon off a little bodily heat and create energy. Furthermore it would use liquid/fluid so it could look and act like a real eye ball full of jelly and everything.

Body Heat AND Solar Power

This has already been done successfully with this smart watch. For solar power, eyes are open for the majority of the time you are awake and a cybernetic one could charge through light energy as you go about your day.

Of course, this would just be a supplement to the main source of energy, body heat. The eye socket is inside the body, which is always much warmer than our outer-layer of skin, especially our wrists.

If the smart watch mentioned above can have so much functionality (step tracking, time, gps, heart rate, calorie counter, etc) while only running on body heat from an extremity, imagine the power that could be generated from a place closer to the center of your body and embedded in it.

And technology will only increase in ability in the future, so I think this would be a very plausible solution .

A quartz crystal

We used quartz crystal to make watches before electronics and batteries were invented. The quartz has a properties that allows to transform mecanical forces into electric charges, and vice versa. For old watches, you had to move the wrist a few seconds to "recharge" the quartz for a few hours.

In your case, the quartz could be linked to the muscles of the eyes: when the muscles move, the quartz charges itself. You wink between 10 to 20 times a minutes, and your eyes moves a lot more, even in your sleep, you could thus have an infinite source of energy for the quartz.