Femtosecond Laser-Assisted Peripheral Additive Stromal Keratoplasty for Treatment of Primary Corneal Ectasia: Preliminary Outcomes
Yasaman Hadi1 *
- Eye Research Center, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
Abstract: Different methods have been used to transfer allogenic corneal tissue to change the strength and shape of an ectatic cornea.
Aim: To report the preliminary results of a new surgical modality for treatment of primary corneal ectasia which consists of implanting allogenic corneal tissue into the peripheral corneal stroma using a femtosecond laser system or Femtosecond laser–Assisted Peripheral Allogenic Stromal Additive Keratoplasty (FA-PASAK).
Methods: This prospective, non-comparative case series includes patients with primary corneal ectasia including keratoconus (KCN) and pellucid marginal degeneration (PMD). In the operating room, one or two ring or crescent-shaped allogenic corneal segments were prepared using a handmade double bladed punch which were then implanted by a specially designed device into stromal channels in the peripheral recipient cornea fashioned with a femtosecond-laser system.
Results: A total of 15 eyes of 13 patients with mean age of 31.2 years were operated. There were significant improvements in uncorrected (0.65 to 0.31 logMAR) and corrected (0.38 to 0.15 logMAR) visual acuity, mean sphere, mean spherical equivalent refractive error and mean keratometry (steep, flat and average). Topographic and refractive astigmatism did not change significantly.
Complications included a single case of bacterial keratitis secondary to epithelial defect which was controlled with topical antibiotics eventually leading to an uncorrected vision of 20/25 one year after surgery.
Conclusion: The use of allogenic corneal rings or crescent shaped segments may be a safe and cost-effective treatment for primary corneal ectasia. A nomogram is necessary to be devised for general use of the technique.
