New microwave thermokeratoplasty and accelerated crosslinking method for keratoconus: Results in 24 eyes during a 1-year follow-up

Abstract

PURPOSE: To evaluate the safety and efficacy of a new microwave thermokeratoplasty procedure combined with accelerated corneal collagen crosslinking (CXL) to improve visual function in patients with keratoconus. SETTING: Cornea and refractive surgery department, Istanbul, Turkey. DESIGN: Prospective clinical trial. METHODS: Patients with keratoconus who had the combined procedure were evaluated over 12 months postoperatively. The main outcome measures were changes in logMAR uncorrected (UDVA) and corrected (CDVA) distance visual acuities and in keratometry (K) values. RESULTS: The study enrolled 24 eyes of 24 patients aged 18 to 45 years. The attempted corrections ranged from -1.60 to -6.50 diopters (D). The mean preoperative UDVA of 0.66 logMAR +/- 0.26 (SD) significantly improved to 0.39 +/- 0.21 logMAR 1 month postoperatively. However by 6 months, the mean UDVA had regressed to 0.58 +/- 0.21 logMAR. At 12 months, the mean UDVA was 0.62 +/- 0.17 logMAR. The mean K value was 49.11 +/- 2.43 D preoperatively, 43.50 +/- 3.04 D 1 month postoperatively, 47.52 +/- 2.99 D at 6 months, and 48.37 +/- 3.00 D at 12 months. There were no cases of significant endothelial cell loss or loss of CDVA lines at 12 months. CONCLUSIONS: The new thermokeratoplasty procedure followed by accelerated CXL produced the desired reduction in K values and improvement in postoperative UDVA without significant side effects. However, the early and complete regression of the thermokeratoplasty effect shows the need for further advancement of this technology.