[Morphological analysis of corneal refractive lenticules--is there a correlation with refractive results?].

BACKGROUND: ReLEx®flex is a corneal refractive procedure performed by removing corneal lenticules with a femtosecond (fs) laser system. Using electron microscopy, tissue parameters of extracted lenticules were analysed for potential correlations to the refractive results. Furthermore, the effect of previous contact lens (CL) wear on refractive stability (regression) was tested.

PATIENTS AND METHODS: 19 lenticules from 11 patients (age 24-56 years, 8 f, 3 m) were prepared for EM. The central areas of the samples were photographed and the distance between the collagen fibres and their diameters were digitally measured. ANOVA analysis was used to correlate postoperative refractional stability with time of preoperative CL use, fibre diameter and the coefficient of variation (CV) of fibre distance.

RESULTS: 14 of 19 lenticules were from patients who had worn CL preoperatively. The cumulative duration of CL wear averaged around 31.2 ± 35.5 thousand hours. Preoperative CL use significantly influenced the postoperative regression: the longer time patients had worn CL, the greater was the regression towards myopia (p = 0.01). Additionally, the morphological parameters collagen fibre diameter (p = 0.09) and CV of fibre distance (p = 0.07) had an impact on regression.

CONCLUSIONS: Prolonged CL use and alterations in ultrastructural patterns affected the refractive stability after ReLExflex. Although the pathophysiological relationships between CL use, corneal morphological parameters, and refractive stability are still poorly understood, these findings could potentially be used as prognostic markers for postoperative refraction after ReLExflex.