Alterations in Corneal Biomechanical and Topographic Features After Accelerated Crosslinking: 1-Year Results

To determine the biomechanical and topographic alterations within the first year after accelerated crosslinking (CXL) treatment in patients with keratoconus.

In this prospective study, 52 eyes of 52 patients with progressive keratoconus underwent accelerated CXL were included. All patients had a detailed preoperative ophthalmologic examination, including slit-lamp evaluation, Goldmann tonometry, fundoscopy, topography by Scheimpflug imaging (Sirius), and corneal biomechanical evaluation with a biomechanical waveform analysis device (ORA). Alterations in visual acuity and topographic findings were evaluated before the treatment and at 12 months follow-up. Corneal biomechanical features were obtained before the treatment, and at 1^st, 3^rd, 6^th and 12^th months.

Uncorrected-visual acuity and best-corrected visual acuity both statistically significantly improved at 12^th month (p=0.001). There were no statistically significant differences in keratometry values, whereas maximum K (AKfront) and symmetry index front (SIfront) decreased significantly (p=0.015 and p=0.009, respectively). Corneal thinnest point and volume also decreased significantly at 12^th month (p=0.001 for both). Goldmann-correlated intraocular pressure (IOPg) and corneal compensated IOP (IOPcc) values transiently increased in the first three months, while corneal hysteresis (CH) and the corneal resistance factor (CRF) transiently decreased, with the difference not statistically significant (p>0.05). However, central corneal thickness significantly decreased at the end of the 12^th month (p=0.001).

Accelerated CXL seems to be effective in stopping the progression of keratoconus. Our findings showed transient alterations in biomechanical features, which will end with the preoperative values at the end of the 12^th month. Further studies are needed to demonstrate the changes in corneal biomechanics in vivo.