Corneal Allogenic Intrastromal Ring Segments (CAIRS) Combined With Corneal Cross-linking for Keratoconus

To describe endokeratophakia in which a small incision lenticule extraction (SMILE) lenticule from a myopic patient is implanted into a recipient eye through a small incision to correct hyperopia.

Purpose: To describe the technique of cryopreservation of corneal lenticules extracted after small incision refractive lenticule extraction (ReLEx SMILE) and initial results of femtosecond laser intrastromal lenticular implantation for hyperopia. Methods: Lenticules were collected from patients undergoing ReLEx SMILE for the correction of myopia and subjected to a tissue processing technique and cryopreservation. These lenticules were subsequently used to treat 8 hyperopic eyes and 1 aphakic eye. A femtosecond laser was used to create a pocket into each patient's cornea, followed by implantation of a cryopreserved lenticule. The patients were monitored through follow-up examinations for a mean 155.4 days (38–310 days). Results: The mean interval from storage of lenticules to removal from liquid nitrogen was 96 days (range, 19–178 days). Mean spherical equivalent of hyperopic eyes treated was +4.50 ± 1.1 diopter (D). Mean keratometry and pachymetry changed from preoperative 43.9 D and 531.6 μm to 47.4 D and 605.2 μm, respectively, postoperatively. Mean residual spherical equivalent for hyperopic eyes was +0.6 D and +4.1 D for the aphakic eye. None of the eyes showed evidence of rejection or loss of best-corrected visual acuity at the end of the follow-up period. Conclusions: The cryopreservation technique seems to be a safe method of long-term storage of refractive lenticules extracted after ReLEx SMILE for use in allogeneic human subjects. It may potentially be a safe and effective alternative to excimer laser ablation for hyperopia because of the low risks of regression, haze, flap-related complications, postoperative dry eye, and higher-order aberrations. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: CTRI/2014/01/004331.