Crosslinking for post refractive surgery ectasia: application and clinical outcomes

PurposePost-laser vision correction ectasia (PLE) is one of the more serious complications that can happen after laser vision correction surgery, manifested as progressive thinning of the cornea and accompanied by increased myopia and irregular astigmatism. We present a case series of PLE managed with pachymetry-guided Epithelium-Off accelerated crosslinking (ACXL) using the M nomogram, in a long term-follow-up evaluation.MethodsBefore-after comparative case series of 13 eyes of 10 patients (3 bilateral treatments) diagnosed with PLE underwent standardized over-the-Flap crosslinking technique (S-ACXL) with epithelial removal (Epi-Off). UV-A irradiation was delivered with continuous and pulsed light mode of irradiation in a range of UV power between 9 and 30mW, customized according to baseline corneal pachymetry (M nomogram), maintaining the standardized fluence.ResultsNo statistically significant differences were found in sim-Kmax, mean pupillary power and Kavg, despite a general tendency to improvement. The stability of the corneal thickness during the entire follow-up in all treated patients confirmed the stabilization of PLE in association with statistically significant reduction (P 0.005) of the posterior elevation (PE). Corrected distance visual acuity showed a statistically significant improvement of + 2 +/- 0.57 Snellen Lines (P = 0.05). Coma, high-order aberrations and Spherical aberrations decreased significantly (P 0.005) explaining the functional improvement. No adverse events were recorded.ConclusionsVisual acuities improved in all patients and the disease was stable over a long-term follow-up, confirming the usefulness of pachymetry-guided ACXL in blocking the progression of PLE at the same time of improving the functional outcomes.What is known?Post-laser vision correction ectasia (PLE) is a rare but serious complication following refractive surgeries like LASIK, PRK, and SMILE. It leads to corneal thinning, irregular astigmatism, and high-order aberrations, resulting in reduced visual acuity and quality of life.Corneal cross-linking (CXL) has been successfully used for years to treat progressive ectasia by strengthening corneal biomechanical stability, halting progression, and, in some cases, leading to visual improvements.What is new?Pachymetry-guided accelerated CXL (ACXL) using the "M nomogram" demonstrates effectiveness in managing PLE. This individualized approach adjusts treatment depth based on baseline corneal thickness, showing significant clinical improvement in visual acuity and corneal stability, with long-term follow-up.Variation in treatment response was observed between post-LASIK, post-PRK, and post-SMILE ectasia. Patients with post-PRK ectasia responded more favorably to ACXL, possibly due to the absence of an interface, which enhances treatment efficacy.