Question: do you do eye implants

anon answered on 16 Jun 2015:

Currently the ophthalmology guys already have ‘eye implants’. There are replacement corneas and lenses. However for replacement retinas there have been one or two experimental devices implanted into patients.

These implants have a very low resolution, at worst tells the patient if it is night or day, at best can provide the user with shape information. The difference between hearing implants and eye implants is the additional complexity.

With cochlear implants we deal with frequencies and change in loudness of these frequencies over time. With eye/retinal implants you need 2D information – 20 your 4MB smart phone camera has 2000 x 2000 picture elements. Each of these elements will need to deal with the brightness. On top of this you will need one set of sensors for each of the primary colours. So the computer processing is a few orders of magnitude more than that for hearing. Where a cochlear implant have an external speech processor sitting behind the ear. The eye implant will need a camera to focus and adapt to the varying light conditions.

After all this it is still low resolution compared with the human eye, where there are around 6.4 million cone cells and 120,000 rods cells. These are cell that react to light. Are crammed into the fovea – organ around 1.5mm in diameter. The normal eye have cones and rod cells which gives resolution or sensitivity respectively. In day time the rods gives sharpness and colour, at night the cone allow you to see but its essentially monochomatic.

So we have a hell of a long way to go to replicate the human eye, but computing power and nano technology will get up there eventually. Eye implants are at a similar currently at a similar development stage to cochlear implants in the late 1960’s and early 1970’s.

http://www.bostonretinalimplant.org/

http://web.stanford.edu/~palanker/lab/retinalpros.html