Femtosecond Lentotomy: Changing the Crystalline Lens Tissue by High Repetition Rate Femtosecond Lasers

Abstract

Purpose: : According to Helmholtz’ theory of accommodation one of the mayor reasons for the development of presbyopia is the increasing sclerosis of the lens. One concept of regaining the elasticity of the lens tissue is the treatment of the lens by femtosecond laser pulses.

Methods: : Our aim was to evaluate changes of crystalline lenses due to the treatment with high repetition femtosecond lasers. We used an IMRA µJewel femtosecond laser with 100 kHz repetition rate to create microincisions in crystalline lenses of human autopsy eyes as well as in porcine and rabbit eyes. The treated eyes were analyzed using OCT and histological sections for detection of the cuts. Mechanical changes were analyzed with Fisher’s spinning test and a lens stretching device.

Results: : The cuts in the crystalline lenses were detectable with OCT. Histological sections show limited thermal and mechanical alteration of the interaction zone. The rotation experiments as well as the lens stretching experiments show an increase in flexibility for the treated lenses.

Conclusions: : Fs-laser induced cuts in the lens lead to a gain in lens flexibility. Due to the high repetition rate the treatment time could be decreased drastically compared to former investigations.

Keywords: presbyopia • accomodation • laser