An alternative treatment for keratoconus is the implantation of Ferrara rings in the cornea itself. This is usually considered in cases of advanced keratoconus, where the cornea is asymmetric and irregular. By implanting the rings in the central periphery of the cornea, it is made less coned and more regular, thereby reducing refractive power and astigmatism and drastically improving eyesight.
The implantation is conducted under local anesthesia and takes around 15 minutes to complete. Special instruments are used to make a ‘corridor’ within the deeper layers of the cornea in which one or two semi-circle rings are placed. A protective contact lens is positioned on the eye instead of a bandage, and a post-operative treatment course of eye-drops is prescribed for weeks following the intervention.
Ferrara rings can be used in synchronization with other corrective methods, e.g. Ultra B2, or, in specific cases with limited PRK treatment.