An intrastromal corneal ring segment (ICRS) (also known as intrastromal corneal ring, corneal implant or corneal insert) is a small device implanted in the eye to correct vision.
The procedure involves an ophthalmologist who makes a small incision in the cornea of the eye and inserts two crescent or semi-circular shaped ring segments between the layers of the corneal stroma, one on each side of the pupil. The embedding of the two rings in the cornea is intended to flatten the cornea and change the refraction of light passing through the cornea on its way into the eye.

Notice the corneal elevation in red due to the intra corneal segment .

Notice :
We could even see the intra corneal segment implanted into the corneal with anterior chamber vue .

Notice :
We could even see the intra corneal segment implanted into the corneal with anterior chamber vue.
Corneal Rings (PDF)