Assessment of corneal topography indices after collagen crosslinking for keratoconus

Riboflavin UVA (collagen crosslinking [CXL]) treatment for keratoconus is a method for stabilizing or improving corneal properties. Our aim was to evaluate changes in corneal topography indices after CXL.

A total of 38 eyes of 25 patients (mean age 29.36 ± 9.7 years) were treated with CXL technique. The follow-up period was 36 months. Slit-lamp examination, visual acuity tests, and pachymetry measurements were performed; in order to obtain the following numerical data, corneal topography (TMS-4; Tomey) was used: simulated keratometry (K1, K2), CYL (cylinder value), SAI (surface asymmetry index), IAI (irregular astigmatism index), SRI (surface regulatory index), ACP (average corneal power), and CEI (corneal eccentricity index). Treatments were performed with In-Pro CCL-Lix (Germany) equipment.

The values of mean K1 (p = 0.82), cylinder (p = 0.73), SAI (p = 0.99), IAI (p = 0.82), SRI (p = 0.73), ACP (p = 0.73), K2 (p = 0.8), and CEI (p = 0.99) showed no significant changes at the end of the examination period. Uncorrected visual acuity remained unchanged (p = 0.32). However, best-corrected visual acuity changed from 0.21 ± 0.17 to 0.12 ± 0.11 in logMAR scale, but this deviation was not considered significant (p = 0.08). No change was observed in intraocular pressure (p = 0.79). Cornea remained clear and during follow-up period no corneal thinning was observed (p = 0.78).

Our results suggest that corneal collagen CXL can be a successful treatment at certain stages of keratoconus, offering a way to stop progression in keratometric indices.