A Case of Advanced Keratoconus Treated Effectively With Double Corneal Allogeneic Ring Segments

In this case report, we aim to describe the use of double-ring segments to treat a case of keratoconus in corneal allogenic intrastromal ring segments (CAIRS). A 23-year-old male with advanced keratoconus presented with decreased vision and agreed to be treated by CAIRS surgery. A modified CAIRS was performed with two ring segments inserted into the upper and inferior tunnels. A significant corneal flattening was observed during an early postoperative period, resulting in an improvement of visual acuity without any complications for more than six months following the procedure. In this case, CAIRS, with the use of double segments in the tunnel, was effective in terms of the ability to flatten the corneal curvature and result in a dramatic improvement in visual acuity.