Comparison Of Customized And Standard Corneal Crosslinking For Ectasia After Laser In Situ Keratomileusis

To evaluate the effect of customized cross-linking in treatment of post-laser in situ keratomileusis (LASIK) ectasia.

Nonrandomized, comparative clinical study.

Twelve eyes of 12 post-LASIK ectasia patients treated with customized corneal cross-linking in Helsinki University Hospital were included in this study. Patients were prospectively followed for 6 months after the procedure. Corrected distance visual acuity (CDVA) and anterior segment optical coherence tomography (OCT) were compared preoperatively, at 1 month and at 6 months. Twelve conventionally cross-linked post-LASIK ectasia patients served as a control group. Furthermore, the patients were divided into 3 subgroups, to see if the asymmetry of the cornea affects the treatment results. 67% of the patients had further follow-up for 13 months on average. 

Visual acuity and corneal tomography showed worsening at 1 month especially after standard cross-linking. The changes were stabilized at 6 months. There were no statistically significant changes in visual acuity or refractive outcomes 6 months after treatment. In a proportion of the patients, who had longer follow-up the visual acuity got significantly better after customized cross-linking (P= 0.03). Regularization of the corneal shape was more evident in C-CXL group, where the inferior superior asymmetry significantly decreased 6 months after cross-linking (p=.01). In a subgroup analysis customized cross-linking reduced corneal asymmetry better in more decentered ectasias. Standard CXL decreased asymmetry in centrally located cones.

Customized cross-linking seems to be as safe and efficient as standard cross-linking in treating progressive post-LASIK ectasia. Advantage over the traditional Dresden protocol is shorter operation time. The results suggest that customized cross-linking could allow faster recovery and have better effect on visual acuity and corneal asymmetry.