Customized Stromal Lenticule Implantation for Keratoconus

Abstract

PURPOSE: To investigate the potential benefit of keratoconus surgery using customized corneal stromal donor lenticules obtained from myopic small incision lenticule extraction (SMILE) surgery by femtosecond laser. METHODS: In this prospective, consecutive, non-comparative series of cases, 22 lenticules were obtained from 22 myopic patients who had SMILE with a lenticule central thickness of greater than 110 µm. The lenticules were implanted in 22 eyes with advanced keratoconus. The lenticules were customized for the purpose of the implantation with either a simple necklace or necklace-with-ring shape (compound form) depending on the corneal thickness and corneal topography configuration of the implanted keratoconic eyes. The lenticules were implanted into a 9.5-mm corneal lamellar pocket created by the femtosecond laser. Changes in densitometry, thickness, confocal microscopy, corrected distance visual acuity (CDVA), and endothelial cell density were investigated. RESULTS: Intrastromal lenticule implantation was successfully performed in all cases without any complication. Corneal thickness showed a mean enhancement of 100.4 µm at the thinnest point. On biomicroscopy, all corneas were clear at 1 year postoperatively and there was a significant improvement in corneal densitometry during the entire follow-up period. Confocal biomicroscopy showed collagen reactivation without any inflammatory features caused by the implanted fresh lenticules. CDVA improved from 0.70 to 0.49 logMAR ( P = .001) and keratometry decreased from 54.68 ± 2.77 to 51.95 ± 2.21 diopters ( P = .006). CONCLUSIONS: Customized SMILE lenticule implantation by femtosecond laser proved to be feasible, resulting in an improvement in vision, topography, and refraction in the implanted eyes. [ J Refract Surg . 2020;36(12):786–794.]

Comparison of the Effects of Temperature and Dehydration Mode on Glycerin-Based Approaches to SMILE-Derived Lenticule Preservation

“…Small-incision lenticule extraction (SMILE) is an increasingly common form of corneal refractive surgery wherein an intrastromal lenticule and a side cut are created with a femtosecond laser, yielding an intact refractive lenticule that can serve as a biomaterial with good optical transmittance, desirable mechanical properties, and excellent biocompatibility. 1 The implantation of such stromal lenticules has been successfully implemented in clinical settings to correct for hyperopia, 2 , 3 presbyopia, 4 , 5 and keratoconus, 6 , 7 and for corneal patch grafting as a means of managing corneal perforations and other ocular diseases. 8 – 10 However, fresh lenticules are generally used in these studies, greatly constraining their utility.…”

Femtosecond laser‐assisted minimally invasive lamellar keratoplasty for the treatment of advanced keratoconus

“…Several studies have demonstrated corneal intrastromal lenticule implantation in patients with Keratoconus. 18,19 Only one case reported intrastromal lamellar keratoplasty in keratoconus. 20 In all these studies, the authors demonstrated the safety of corneal intrastromal lenticule implantation without any complications that were consent with our present study.…”

“…Several studies have demonstrated corneal intrastromal lenticule implantation in patients with Keratoconus 18,19 . Only one case reported intrastromal lamellar keratoplasty in keratoconus 20 .…”

Corneal Stromal Regeneration: A Review of Human Clinical Studies in Keratoconus Treatment

“…Allogenic refractive lenticule corneal inlay using a SMILE lenticule combined or not with accelerated collagen cross-linking (28,29,31,33), is a promising surgery, no inflammation, complication, opacification, vascularization, or infection were recorded. Another group performed a recent prospective study in Tehran (39), they reported a novel method for the treatment of advanced ectasia, with customized SMILE lenticule implantation with 22 cases of advanced keratoconus (shape of the lenticule was compound form or necklace). Corneal thickness showed a mean enhancement of 100.4 µm at the thinnest point measured by AS-OCT. An improvement in visual parameters was obtained, best CDVA improved from 0.70 (range 0.4-1) to 0.49 (range 0.3-0.7) at 6 months with all the patients, which was in coherence with the decrease in corneal aberration, also keratometry decreased from 54.68 ± 2.77 to 51.95 ± 2.21 (D) was obtained.…”

“…Other recent studies of endokeratophakia using regular SMILE lenticules have shown to be a feasible option to correct ametropias such as hyperopia, presbyopia or to increase the thickness in the keratoconic cornea (40). Nevertheless, the use of customized positive meniscus lenticules in keratoconus corneas is debatable (29,39), as theoretically could worsen myopia usually encountered in such patients, and so planar or negative meniscus lenticules are always preferable for such purpose. Implantation of autologous fresh lenticules from SMILE for hyperopia was wellintegrated into the host stroma (41,42).…”