But we're using a lens that bends spacetime. I'm not sure index of refraction is relevant. On the recent image from JWST, I don't see any refraction artifacts o

But we're using a lens that bends spacetime. I'm not sure index of refraction is relevant. On the recent image from JWST, I don't see any refraction artifacts on the lensed images of galaxies. https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-delivers-deepest-infrared-image-of-universe-yet https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-...