Porcine Collagen Implants in Advanced Keratoconus: Outcomes at 1 Year

Purpose To report the visual and tomographic outcomes 1 year after porcine collagen lenticule implantation in eyes with advanced keratoconus. Methods Patients older than 18 years with advanced keratoconus having central corneal thickness (CCT) greater than 350 µm and visual acuity of 20/40 or better with contact lens, but intolerant to contact lenses, were included. A femtosecond laser–assisted stromal pocket was created at a depth of 140 µm. A Xenia implant (Gebauer Medizintechnik GmbH) was inserted into the stromal pocket using a glide. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity testing, slit-lamp evaluation, corneal topography using Pentacam (Oculus Optikgeräte GmbH), and anterior segment optical coherence tomography using Optovue (XR-Avanti) was performed preoperatively and at 1 week, 1, 3, and 6 months, and 1 year after Xenia lenticule implantation. Results Nine eyes of 9 patients (6 men and 3 women) with a mean age of 28.4 years underwent Xenia lenticule implantation. Mean UDVA and CDVA improved from 1.43 ± 0.3 to 0.78 ± 0.17 logMAR ( P = .0087) and 0.89 ± 0.13 to 0.45 ± 0.03 logMAR ( P = .0005) at 1 year. The preoperative mean flat keratometry (K1) was 61.29 ± 3.76 diopters (D), steep keratometry (K2) was 68.09 ± 4.41 D, CCT was 354.71 ± 9.30 µm, average keratometry (Kmean) was 64.50 ± 3.98 D, and maximum keratometry (Kmax) was 77.07 ± 6.01 D. All keratometry values showed statistically significant flattening at 1 year with mean K1 of 40.70 ± 3.96 D ( P = .0003), K2 of 43.80 ± 4.04 D ( P = .0005), Kmean of 42.20 ± 4.00 D ( P = .0003), and Kmax of 61.53 ± 4.70 D ( P = .0152). There were no episodes of graft rejection. Two eyes had stromal melt within 3 months postoperatively, requiring lenticule explantation. Conclusions Significant improvement in UDVA, CDVA, and keratometry values was noted in patients undergoing Xenia lenticule implantation in advanced keratoconus. Preliminary results demonstrate that Xenia lenticule implantation could be an alternative to keratoplasty and human stromal lenticule implants in cases with advanced keratoconus. [ J Refract Surg . 2025;41(3):e272–e279.]