Femtosecond Laser-assisted Keyhole Endokeratophakia: Correction of Hyperopia by Implantation of an Allogeneic Lenticule Obtained by SMILE from a Myopic Donor

Purpose: 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.

Methods: A 23-year-old aphakic woman presented following cataract surgery to remove a childhood congenital cataract with hyperopia of +12.00 -1.50 × 155, corrected distance visual acuity of counting fingers, and exotropia. A SMILE procedure using the VisuMax femto-second laser (Carl Zeiss Meditec, Jena, Germany) was performed on a donor patient with high myopia and the extracted lenticule was stored (power -10.50 diopter sphere, optical zone 5.75 mm, central lenticule thickness 127 μm). In the recipient eye, a pocket lamellar incision was created using the VisuMax SMILE software. The upper interface was separated and the donor lenticule was inserted through the small incision.

Results: One year postoperatively, retinoscopy refraction was +7.50 -3.00 × 150, a spherical equivalent refraction reduction of 5.25 diopters. Mean keratometric power increased by 2.91 diopters. The posterior surface elevation changed significantly with a central bulge into the anterior chamber. Central corneal thickness by Pentacam (Oculus Optikgeräte, Wetzlar, Germany) increased by 121 μm. Central lenticule thickness was 130 μm and central epithelial thickness was 43 μm measured by RTVue OCT (Optovue Inc., Fremont, CA). The cornea remained clear over the 1-year postoperative period.

Conclusions: Endokeratophakia appears to be a viable procedure for correcting hyperopia on the cornea by implantation of an extracted myopic SMILE lenticule from a donor patient. However, posterior surface changes and epithelial remodeling resulted in only 50% of the intended correction. No adverse side effects were observed following implantation of donor tissue for 1 year.