Purpose
To evaluate the visual and topographic outcomes of corneal collagen crosslinking (CXL) in keratoconic eyes at different stages 1 year after CXL.
Methods
Retrospective, consecutive clinical study. Sixty-three keratoconic eyes that were underwent CXL were divided into three groups as a function of stage of keratoconus (stages I, II and III). There were 23 eyes with stage I, 21 eyes with stage II and 19 eyes with stage III. Outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA) and corneal topography which were performed before and 12 months after CXL.
Results
For stage I, the mean pre-CXL UDVA was 0.84±0.72 logMar, while post-CXL UDVA was 0.49±0.35 logMar (p=0.03). There were no statistically significant change in the mean pre-CXL and post-CXL CDVA, flattest meridian keratometry (K), steepest meridian K, average K, and apical K (p>0.05 for all variables). For stage II, the mean pre-CXL UDVA was 1.20±0.64 logMar, which was changed to 0.72±0.33 logMar after CXL (p=0.03). The mean pre-CXL steepest meridian K and apical K were 53.26±2.33 D and 61.97±5.64 D respectively. They were significantly decreased to 52.912±.20 D and 60.804±.69 D respectively (p=0.03, p=0.013, respectively). The mean pre-CXL and post-CXL CDVA, flattest meridian K, and average K did not show any significant difference (p>0.05 for all variables). For stage III, the mean pre-CXL flattest meridian K, steepest meridian K, average K and apical K were significantly decreased from 53.21±1.16 D, 58.40±2.66 D, 55.661±.62 D, 66.05±3.81 D to 52.48±1.30 D, 57.262±.75 D, 54.851±.78 D, 65.15±3.35 D after CXL respectively (p=0.001, p=0.001, p=0.001, p=0.001). There were no significant change between the pre and post-CXL UDVA and CDVA (p>0.05 for both variables).
Conclusions
One year postoperatively, the effects of CXL on vision was more significant in early and moderate stages of keratoconus, while the topographic improvement was more prominent in advanced stage.
Keywords: 574 keratoconus