Topography-guided, patterned, customized corneal crosslinking for non-invasive astigmatism correction.

Objectives: To propose and evaluate a novel, non-invasive approach for enduring corneal astigmatism correction based on topography-guided, patterned, customized riboflavin-ultraviolet A corneal collagen crosslinking (CXL).

Methods: Astigmatism was modelled on both eyes of rabbits. A randomly selected eye of each rabbit was treated by the proposed CXL procedure with another eye as control. The proposed procedure was performed by a self-built intelligent platform through delivering ultraviolet A lattice in a refined and patterned manner, based on pre-operative corneal topography. The long-term effectiveness, stability, and safety were investigated for 180 days, with topographic measurements, anterior segment optical coherence tomography (AS-OCT), and in vivo corneal confocal microscopy (IVCM).

Results: Spatially selective demarcation lines in AS-OCT images and trabecular patterned hyperdense structure with abundant needle-like processes in IVCM images were detected in the CXL eyes, revealing spatially selective crosslinking. Reductions of astigmatic magnitude (in the steep axis: 0.46 ± 0.28 vs. 2.15 ± 0.58 dioptres, P < 0.001) and high order aberration (0.38 ± 0.18 vs. 0.59 ± 0.19, P = 0.009) with increase of visual strehl ratio (0.21 ± 0.06 vs. 0.13 ± 0.03, P < 0.001) were found in the CXL eyes after CXL and maintained for 180 days, compared to inconspicuous changes in the control eyes. No obvious opacity and inflammation were observed in the CXL eyes, and transient loss of endothelial cells in the treated area was recovered in the subsequent visit.

Conclusions: The proposed novel, non-invasive approach safely fulfilled corneal astigmatism correction with visual quality improvement as well as a decrease in high-order aberration.