[orthoxerox]

Last year I got a new prescription and the optometrist convinced me to switch to higher refractive index lenses, because they are thin, light, don't have a subtle yellow hue like CR-39, don't distort the facial features and so on. I agreed and couldn't wear them at all due to insane chromatic aberration. After a few complaints they relented and replaced the lenses with CR-39 and I have been happy ever since.

[tenken]

Do you mean "High Index" lenses? ... I have strong prescriptions of -9.x and -11.x and I have had 1.66 index lenses. I've always noted to doctors light sources move around or float around alot with the lenses. I haven't necessarily noticed a difference with contacts (but I did see sharper with hard contacts) but my eyes cannot tolerate hard or soft lenses.

I have tried even higher index lenses, but anything above 1.66 and the distortions and optical aberrations get too annoying ...

[orthoxerox]

Yes, high refractive index lenses. -9 and -11 sound like actually good reasons to recommend them, at these levels of myopia lower index glasses should be noticeably heavier.

What I couldn't tolerate was specifically chromatic aberration. Every letter in this text box would have a yellow and blue fringe if my head was turned even slightly. And this would happen with every high-contrast border, like someone's t-shirt, a white car or a house against the sky.