Small-Incision Femtosecond Laser–Assisted Intracorneal Concave Lenticule Implantation in Patients With Keratoconus

PURPOSE: To evaluate the feasibility and efficacy of small-incision femtosecond laser–assisted intracorneal concave lenticule implantation (SFII) and penetrating keratoplasty (PKP) in patients with progressive keratoconus. METHODS: All the patients were clinically diagnosed with progressive keratoconus. Twenty patients underwent PKP (PKP group), and 11 patients underwent SFII (SFII group). Visual acuity, intraocular pressure, corneal topography, corneal visualization Scheimpflug technology, anterior segment optical coherence tomography, and in vivo confocal microscopy were analyzed. RESULTS: Vision improved at 3 months postoperatively in the SFII group. In the PKP group, corrected distance visual acuity improved 1 week after surgery. Corneal topography showed a statistically significant decrease in the anterior K1 and K2. Corneal visualization Scheimpflug technology showed that changes in the biomechanical parameters of the SFII group were also statistically different from those of the PKP group. All the grafts from both groups were clearly visible by anterior segment optical coherence tomography observation. The central corneal thickness of both groups was stable during the 24-month study period. In vivo confocal microscopy showed a few dendritic cells in the subepithelial region in the SFII group. At 3 months after surgery, many dendritic cells and inflammatory cells were observed in the basal epithelium and stroma in the PKP group. CONCLUSIONS: Both SFII and PKP surgical procedures resulted in a stable corneal volume and improved visual acuity in this long-term study. SFII was less invasive and more efficient compared with PKP.