Comparison of Customized and Standard Corneal Cross-linking for Ectasia After Laser in Situ Keratomileusis

To evaluate the effect of customized corneal cross-linking (CXL) in ectasia after laser in situ keratomileusis (LASIK).

Thirty-two eyes of 24 patients with post-LASIK ectasia treated with customized CXL were included in this study. Treatment zones with different ultraviolet energy levels were planned according to corneal tomography. A control group of 19 eyes of 14 patients with post-LASIK ectasia received conventional CXL. Patients were prospectively followed up at 1 month, 6 months, and 1 year after the procedure. Subsequent follow-up 2 to 4 years after CXL was obtained from 22 eyes of 18 patients. Corrected distance visual acuity, refraction, and anterior segment optical coherence tomography parameters were compared to preoperative values.

After a transient deterioration at 1 month, visual acuity and keratometry stabilized at 6 months in both groups. One year after customized CXL, the visual acuity was significantly better (P< .01), corneal inferior-superior asymmetry decreased (P = .02), and corneal thickness increased (P < .01). These effects were maintained during the 2- to 4-year follow-up. There were no statistically significant changes in refractive outcomes or keratometry at 1 or 2 to 4 years. Decrease in higher order irregularities was seen only after customized CXL, but it did not reach statistical significance. In 1 patient the ectasia continued progressing after customized CXL, giving a failure rate of 4.2%.

Customized CXL seems to be as safe as standard CXL in treating progressive post-LASIK ectasia. The results suggest that customized CXL could have a better effect on visual acuity and corneal asymmetry. More studies are needed to verify the advantages of customized method over standard CXL.the [.