Can we directly stimulate M cones in retina with current technology?

Question

I wonder if we could try to see imaginary "supergreen" color by directly stimulating M cones. For this I suppose we'd need:

1. Non-destructively scan specific human's retina to locate exact positions of M cone cells.
2. Prepare a high-resolution image (on a retina-like display I guess), which would have light spots in some locations and dark in others, so that when the human we inspected looks at particular point of the image, these light spots were focused exactly on M cones.
3. Track the eye movements and adjust the image so that S and L cones avoided significant exposure to prevent misperception.

Is anything of this hard to implement with current technology, given typical human retina properties (M cones density, their apparent color etc.)?

If this is totally possible, has such an experiment already been performed?

Answer 1

You've probably seen the news reports by now, in which researchers targeted and stimulated individual cone cells in the eyes of volunteers: "The elementary representation of spatial and color vision in the human retina" Ramkumar Sabesan, et. al. (2016). This experiment is the first time that researchers have targeted and stimulated individual cone cells. The experiments mostly involved L- and M-Cones, though the published research noted the response obtained from S-Cones, too. The researchers used 543 nm laser light (25 nm bandwidth) and an optical tracking system similar to what astronomers use to correct atmospheric distortions. So, yes, the technology exists, but it looks like it is so new in this application that no one has performed other experiments with it, yet.

Answer 2

Technology is not advanced enough to achieve receptor-specific stimulation. Regarding your defined needs:

1) Identifying M cones: It is already challenging to distinguish cones from rods in the retina (Turpin et al, 2011), let alone identify the three classes of cones.

2) Your retinal-mosaic image would theoretically be possible, although very small pixels would be needed.

3) Eye tracking is doable, but not at this level of accuracy. Delays in the system will almost certainly result in transient activation of other receptors.