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U. Oberheide, T. Ripken, S. Schumacher, M. Fromm, G. Gerten, H. Lubatschowski; Increase Of The Elasticity In Crystalline Lenses After Treatment With Femtosecond Laser Pulses . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5889.
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© ARVO (1962-2015); The Authors (2016-present)
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 material is the treatment of the lens by femtosecond laser pulses.
Our aim was to evaluate potential elasticity changes of fs–laser treated crystalline lenses with different cutting geometries. We performed different cutting patterns in 190 enucleated porcine (ex vivo) and 17 human autopsy lenses. The age of the human donors ranged between 37 and 59 years. The laser pulses had a repetition rate of 5 kHz and a pulse duration of 120 fs. The pulse energies and spot separation of the laser pulses were varied to investigate the effect on the generated cut. For an evaluation of the gain in elasticity the lenses were rotated before and after treatment and the changes in the lens’ thickness was measured (Fishers Spinning Test).
The rotation experiments showed an increase of elasticity for all eyes. Depending on the used geometry for the cut the elasticity could be increased between 3 and 27% for the porcine lenses and 17 to more than 70% for the human lenses. Since the age of the human donors had a broad range, leading to different degrees of lens hardening, the variance of the measured elasticity changes was up to 10%.
Fs–laser induced cuts in the lens lead to a gain in lens elasticity. This might be a possibility for presbyopia treatment in phakic eyes. Further investigations which show a correspondence of gain in elasticity and change of accommodative power as well as wound healing studies have to be performed.
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