Enhanced-Fluence Pulsed-Light Iontophoresis Corneal Cross-linking: 1-Year Morphological and Clinical Results

PURPOSE: To assess the safety and efficacy of a novel pulsed-light enhanced-fluence iontophoresis corneal cross-linking (EF I-CXL) procedure in patients with progressive keratoconus. METHODS: This prospective interventional pilot study included 12 eyes of 10 patients. Iontophoresis with Ricrolin+ solution (Sooft, Montegiorgio, Italy) was used for stromal imbibition. The treatment energy dose (fluence) was optimized at 30% (from 5.4 J to 7 J/cm(2)) and ultraviolet-A (UV-A) power set at 18 mW/cm(2) x 6.28 minutes of exposure time, pulsing the light 1 second on/1 second off with a total irradiation time of 12.56 minutes. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), Scheimpflug corneal tomography data, and corneal optical coherence tomography (OCT) at baseline and 1, 3, 6, and 12 months postoperatively were evaluated. RESULTS: Twelve-month statistically significant average data (P<.05) showed UDVA decreased from 0.50 +/- 0.10 to 0.36 +/- 0.08 logMAR, maximum keratometry decreased from 52.86 +/- 1.50 to 51.49 +/- 0.90 diopters (D), surface asymmetry index decreased from 2.34 +/- 0.36 to 2.13 +/- 1.12 D, symmetry index decreased from 4.22 +/- 1.01 to 3.56 +/- 0.90 D, and coma decreased from 0.25 +/- 0.05 to 0.14 +/- 0.06 mu m. Corneal OCT showed greater than 80% demarcation line detection at 295.8 +/- 20.2 mu m depth on average in the first postoperative month. CONCLUSIONS: The preliminary results of the EF I-CXL protocol demonstrate its capability to increase I-CXL efficacy closer to standard CXL.