I don’t see an iPhone or similar device getting OCT-like images anytime soon. They need special optics to image the whole retina (although I can imagine image processing hacks to work around that at the expense of exam speed), but they also require an optical system that’s quite unlike a normal camera to acquire an image at all.
I think the real issue with OCT cost is machine utilization. An OCT machine is cheap as medical devices go, but, in the usual US model, it gets extremely low utilization. It takes a minute or so to get a scan, it’s completely painless and requires neither dilation or any particular expertise, but the machines only get used a couple times a day.
A venue like Costco or a comparably busy place in a different country could probably offer walk-up OCT scanning for a couple dollars or maybe even free and encourage people to do it once per year. If the FDA played along, software could likely analyze the images and detect the progression of quite a few diseases, several of which would be treatable.
(A brand new machine seems to
cost something like $20k. If it gets used 60 times per day (credible for a large scale user but not for a small shop), $1 of revenue per scan gives an adequate payback.)