Anterior and posterior corneal changes after crosslinking for keratoconus

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Surgery

Background:

• Progressive keratoconus is a degenerative corneal disease characterized by thinning and steepening.
• Corneal crosslinking (CXL) is a standard treatment to halt keratoconus progression.
• Evaluating anterior and posterior corneal changes post-CXL is crucial for assessing treatment efficacy.

Purpose of the Study:

• To assess anterior and posterior corneal topographic and tomographic changes following corneal crosslinking (CXL) in patients with progressive keratoconus.
• To determine the long-term (2-year) effects of CXL on corneal shape and thickness.

Main Methods:

• Retrospective analysis of Scheimpflug imaging (Pentacam) from 20 eyes with keratoconus before and 2 years after CXL.
• Statistical analysis of topographic, tomographic, and pachymetric parameters using analysis of variance.
• Evaluation of the spatial relationship between maximum anterior keratometry (Kmax) and thinnest point corneal thickness (TPCT) relative to the corneal apex.

Main Results:

• Significant reduction in keratometry (flat and steep meridians) and surface irregularity indices (index of surface variance, index of highest decentration) 2 years post-CXL.
• Decrease in anterior corneal apex elevation, but a significant increase in posterior corneal apex elevation.
• Corneal thinning at the apex and the thinnest point was observed, increasing apical-peripheral pachymetry progression.
• The positions of Kmax and TPCT remained stable.

Conclusions:

• Corneal topography and tomography are valuable tools for monitoring CXL treatment in keratoconus.
• While CXL effectively reduces anterior corneal steepness, the increase in posterior elevation may indicate continued ectatic changes in the posterior cornea.
• Further investigation into posterior corneal changes post-CXL is warranted to fully understand long-term outcomes.