Meniscus-Shaped Stromal Lenticule Addition Keratoplasty for Corneal Regularization and Thickening in Advanced Keratoconus

Abstract

The aim of this study was to investigate the outcome of the meniscus-shaped stromal lenticule addition keratoplasty (MS-SLAK) in corneal regularization and thickness.Methods: Patients waiting for deep anterior lamellar keratoplasty for advanced keratoconus with an intolerance to contact lenses (CLs) underwent the MS-SLAK procedure by FSL 80 kHz ablation (VICTUS, Technolas Perfect Vision, DE). Customized positive meniscus-shaped stromal lenticules were obtained and implanted. Examination was performed at baseline and at 3-, 6-, and 12-month follow-up and included corrected distance visual acuity both with spectacles and CLs (spectacle CDVA and CL-CDVA), manifest refraction spherical equivalent, slit-lamp examination, anterior segment optical coherence tomography, corneal topography, and in vivo confocal microscopy.Results: Fifteen patients completed the study. Statistical increases in corneal thickness values were found from the first follow-up (P , 0.001). Improvement in the Surface Asymmetry Index (P = 0.04), Symmetry Index (P = 0.02), spherical aberration (P , 0.001), coma (P= 0.18), high-order aberration (P = 0.37), and anterior asphericity index (Q) (P = 0.31) were found at 12 months. At the 12-month follow-up, no improvement were found in spectacle CDVA (P = 0.23); however, all patients reported CL wearing tolerance recovery, and significant improvement in CL-CDVA (P = 0.002) was found. The confocal microscopy at 12 months showed a significant increase in keratocyte density within the lenticule and absence of fibrotic reactions in both anterior and posterior interfaces.Conclusions: MS-SLAK seems to be effective in regularizing the corneal surface as showed by the significant improvement in topographic symmetry indices, coma, and high-order aberration. The corneal regularization is also confirmed by the results in anterior Q and the recovery of the CL wearing tolerance.

Customized Bowman-Stromal Inlay: An Attempt to Change the Topography of the Keratoconus Cornea

“…Collagen crosslinking was not performed in these intrastromal augmentation surgeries and was still found to be effective in causing stabilization of ectasia. 4,10,11,17,[25][26][27][28][29][30] Furthermore, we agree that the above-said publications have a low number of patients and that associated CXL can be performed in these patients during the surgery or as a secondary procedure later. Similarly, in the patients presented in the present manuscript, in case ectasia progresses, crosslinking can always be performed and with a safer pachymetry.…”

Cutting Edge: Corneal Stromal Lenticule Implantation (Corneal Stromal Augmentation) for Ectatic Disorders

“…Decellularization is another option that can be used to remove immunogenic macromolecules from allogenic lenticules. 5 Although investigative procedures such as the transplantation of Bowman or Descemet membrane 3 into the mid-stroma of advanced keratoconus eyes have been suggested by the scientific community, they have yet to be explicitly accepted.…”

“…These procedures are named based on the differences in the pocket depth, diameter, and thickness of the lenticule. 1,3…”

“…These procedures are named based on the differences in the pocket depth, diameter, and thickness of the lenticule. 1,3 Stromal lenticule implantation, whether from a donor eye or a fresh eye, may provide a suitable substitute for keratoplasty in advanced keratoconus cases. The distance of the implanted lenticule from the limbal lymphatic vessels and protection from cytokines and immune cells in the tear fluid of the ocular surface may provide greater immunological value than deep anterior lamellar keratoplasty/PK.…”

Tissue addition keratoplasty in keratoconus: Trends and concerns

“…[ 9 12 ] Studies on ISKP reported in literature till date differ in the selection criteria of cases, follow-up periods, lenticule details, depth of lenticule implantation, and combination with collagen crosslinking treatment. [ 9 12 13 14 15 16 17 18 19 20 21 22 23 24 ] While the lenticules used for tissue addition keratoplasty have been described as concave, convex, lamellar, or powered lenticules, the understanding of the change in corneal morphology effected by these is still evolving. The implanted lenticule has been noted to retain its transparency, and confocal microscopy observation shows activated keratocytes both in the host stroma and in the lenticule in the initial 3 months following implantation.…”