Abstract
Abstract: :
Purpose: To assess stromal modifications occurring after IntraLase femtosecond laser for laser in situ keratomileusis (LASIK) using in vivo confocal microscopy. Methods: 12 eyes from six patients were examined, after obtaining their informed consent, during the follow–up of IntraLase femtosecond laser for LASIK surgery, at 1 week and 2 months. Corneal changes were examined using the Heidelberg Retina Tomograph (HRT II) Cornea Module from Rostock university. The morphological patterns of the epithelial layer, stromal matrix, corneal nerves, keratocytes flap interface and the analysis of the flap margin were evaluated and compared with those observed in a matched series of 12 eyes undergoing LASIK with a standard mechanical microkeratome. Results: Evaluations at day 7 showed at the same time a depletion and activation of keratocytes on both sides of the interface. We also observed some brightly reflecting particles together with scattered less bright dots, from day 7 increasing at 2 months. Some clinically visible deposits at the level of the interface, were constantly observed at the periphery at day 7 and could represent cell–degradation products. By confocal microscopy, it appeared as homogeneous reflective deposits with a bigger size than particles and decreased at 2 months. The flap margin microscopically appeared like a very clear–cut edge, including epithelial cells, while those done with a mechanical microkeratome appeared as a badly limited fibrotic scar. We also observed a secondary fibrotic reaction at 2 months adjacent to the still well defined IntraLase flap edge. Conclusions: : This study showed an important morphological similarity between the interfaces obtained with the femtosecond laser and the mechanical microkeratome. The discovery of brightly reflecting particles in the IntraLase interface goes against the hypothesis of the metallic origin of these deposits. The flap margin microscopically looked extremely well delimited, but seemed to provoke an adjacent secondary fibrotic reaction, both microscopically and macroscopically, more important at 2 months than after a mechanical microkeratome cut.
Keywords: refractive surgery • cornea: stroma and keratocytes • imaging/image analysis: clinical