Scheimpflug camera changes after cross-linking for keratoconus

ObjectivesThe aim of our study was to evaluate corneal changes after corneal collagen cross-linking (CXL) in progressive keratoconus with Pentacam Scheimpflug imaging.BackgroundCorneal collagen CXL using ultraviolet A light and riboflavin was introduced as a method to halt the progression of keratoconus. Scheimpflug imaging is considered among the most prevalent modalities in the diagnosis, staging, and follow-up of keratoconus patients.Materials and methodsThis study was a prospective interventional study that included 23 eyes of 18 patients with a mean age 23.39 ± 5.83 years with keratoconus. All underwent corneal collagen CXL using riboflavin and ultraviolet A light. Uncorrected visual acuity and best-corrected visual acuity were assessed. Pentacam's K1 , K2 , thickness at thinnest corneal point, anterior corneal elevation, posterior corneal elevation, cylindrical power and axis, and aberration coefficient were all determined before CXL, 3, and 6 months after CXL.ResultsThere was improvement of uncorrected visual acuity from 0.16 ± 0.2 to 0.24 ± 0.21 (P = 0.001) and best-corrected visual acuity from 0.46±0.19 to 0.63 ± 0.24 after 6 months (P < 0.001). Significant decreases after 6 months were found in keratometry values: K1 from 47.69 ± 4.02 to 47.04 ± 4.43 D (P = 0.004) and K2 from 51.74 ± 4.76 to 51.03 ± 4.92 D (P < 0.001). In addition, there was decrease in thickness at thinnest corneal point from 448.04 ± 32.3 to 438.35 ± 35.42 mm (P = 0.025), anterior elevation from +34.17 ± 13.6 to +30.65 ± 11.11 mm (P = 0.06), and posterior elevation from +74.04±25.71 to +67.39 ± 23.09 mm (P = 0.03). Corneal cylinder and aberration coefficient showed stability with no significant change.ConclusionThere is increasing evidence that CXL does not only halt the progression in the keratoconic eye by corneal tissue strengthening, but also improves visual outcomes and corneal shape, which are against the natural course of the disease.