Purpose
Corneal crosslinking is a procedure used to halt the progression of keratoconus. Its efficacy and safety have been proven through many investigations. However, whether visual acuity and spherical, coma, and/or higher-order aberrations can be significantly decreased by corneal crosslinking remains controversial. In the present study, we assessed anterior corneal parameters before and after corneal collagen crosslinking in patients with progressive keratoconus.
Methods
Twenty-one eyes of 20 patients (7 female and 13 male patients; age, 21.4 ± 5.9 years) with progressive keratoconus underwent corneal crosslinking. In addition to the usual ophthalmic examinations, topographic assessment was performed using Fourier domain optical coherence tomography (SS-1000; Tomey, Nagoya, Japan) before and 1 year after the surgery. Additionally, the best-corrected visual acuity (BCVA), manifest refractions, steepest keratometric value, thinnest corneal thickness, and the values for spherical and irregular astigmatism as well as for corneal asymmetry and higher-order irregularities obtained by Fourier analysis were compared before and after the surgery.
Results
The BCVA, spherical equivalent and cylinder power of manifest refraction, steepest keratometric value, and thinnest corneal thickness were not significantly different before and after the surgery. Fourier analysis showed that spherical and regular astigmatism were not significantly different before and 1 year after the surgery; however, corneal asymmetry and higher-order irregularities were significantly reduced after the surgery for diameters of both 3 mm (p = 0.0053 and 0.0333, respectively) and 6 mm (p = 0.0121 and 0.0174, respectively). Furthermore, positive correlations between the preoperative value and the difference between the preoperative and 1-year postoperative values were observed for both corneal asymmetry (p < 0.0001) and higher-order irregularities (p < 0.0001).
Conclusions
Corneal crosslinking improved corneal asymmetry and higher-order irregularities, especially in eyes with greater asymmetry and higher-order irregularities before the procedure.