1. Lit. Scarring of the retina due to scratching.
2. Urb. When something is so bright, it leaves an afterimage on your eyes for a long time.
3. Urb. When you see something so vile, so disgusting, so horrible, that the image burns into your retinas and can not be unseen.
1. Why are you going in for lasik surgery? Because I have retinal scarring.
2. Wow, your computer screen is so bright, the boot-up screen is scarred into my retinas.
3. I visited 4chan the other day and even though I stayed in the work safe section, there just seems to be no way to avoid the retinal scarring. You can't get /b/ out with eye bleach.