Keratoconus vision correction with ICRS (Intracorneal Ring Segments)

One of the first surgical options for rehabilitating vision in corneas with ectasias like keratoconus was the use of intracorneal ring segments (ICRS). ICRS were introduced in the late 1990s by Joseph Colin in France.

ICRS adjust the corneal shape, aiming for greater symmetry by redistributing the forces of the cornea. In these procedures, surgeons mechanically create a tunnel in the peripheral cornea. Either manually or by means of a femtosecond laser, and insert the ring segments inside them. This raises the peripheral cornea and results in a flattening of the keratoconus in the center, making the cornea more regular and symmetrical.

This increase in symmetry leads to an improvement of visual quality and visual acuity.

However, these ring segments are made from polymethyl methacrylate (PMMA), a synthetic material, and this comes with certain disadvantages, including increased halos in the periphery of the visual field and can even lead to complications such as migration towards the surface of the cornea or the interior of the eye.