To study the safety and clinical outcomes of ReLEx SMILE with accelerated cross-linking in eyes with Subclinical keratoconus.

Fifty-six eyes with forme fruste keratoconus and/or irregular corneas, corrected distance visual acuity 20/40 or better, stable refraction of at least 1 year, age 18 years or older, and residual corneal thickness of greater than 400 mm before performing collagen crosslinking were studied.Following the removal of lenticule, 0.25% riboflavin in saline was injected into the interface and allowed to diffuse for 60 seconds. Finally, eye was exposed to UV-A radiation of 45mW/cm2 for 75 seconds through the cap. Total energy delivered was 3.4 J/cm2.

56 eyes of 28 patients with mean age of 26.75 ± 5.99 years were treated. Mean follow-up was 6 months ± 28.12 days. Mean spherical equivalent (SE) was −5.02 ± 2.06D preoperatively and −0.24 ± 0.18D postoperatively. The mean central corneal thickness (CCT) and keratometry changed from 501 ± 25.90 𝜇m to 415 ± 42.26 𝜇m and 45.40 ± 1.40D to 41.2 ± 2.75D, respectively. Mean uncorrected visual acuity (UCVA) was 20/25 or better in all eyes. No eyes lost lines of corrected distant visual acuity (CDVA). There were no complications like haze, keratitis, ectasia, or regression.

Based on the initial clinical outcome it appears that SMILE Xtra may be a safe. although further follow-up and larger samples are needed to fully confirm these findings, the results suggest that combined small-incision lenticule extraction and intrastromal corneal collagen crosslinking are a promising treatment option for patients for whom conventional laser refractive surgery is contraindicated.