Abstract

Presbyopia is an age related effect which affects every human at the age of about 40 years. So far reading glasses are the conventional treatment. According to Helmholtz’ theory of accommodation one of the mayor reasons for the development of presbyopia is the increasing sclerosis of the lens. In contrast to that the ciliary muscle and the lens capsule remain mostly active and elastic the whole life. So a possible treatment could be the increase of the flexibility of the lens by creating gliding planes with fs-laser pulses inside the lens tissue.

In former studies it was shown that fs-laser pulses were able to increase the flexibility of ex vivo porcine lenses as well as ex vivo human donor lenses. Our current aim was to evaluate the effect of the fs-laser pulses on the crystalline lens of living rabbit eyes due to the fs-lentotomy treatment. The main focus of the evaluation was the exclusion of possible side effects of the treatment like cataract formation or retina damage. The treated eyes were monitored using optical coherence tomography (OCT) and Scheimpflug imaging for localizing and studying the tissue effects of the incisions. Furthermore histological sections of the lens and retina were prepared. The rabbits were investigated pre operatively and up to six months post operatively.

The fs-laser induced micro incisions were successfully applied to the left lens of each rabbit. The micro incisions within the crystalline lens were detectable with OCT and Scheimpflug imaging up to six month. The imaging within the lens showed a progressive fading of the incisional opacities generated by the femtosecond laser during the six months and no indication of cataract formation was found. OCT and Scheimpflug images emphasize themselves as necessary tools to monitor the micro incisions over time. Histopathological sections of the lens tissue support the findings of the non invasive imaging techniques. Also the histopathological sections of the retina show no thermal induced change due to the irradiation of the fs-pulses.

© 2009 OSA/SPIE