fs-Laser induced elasticity changes to improve presbyopic lens accommodation.
BACKGROUND
According to the Helmholtz theory of accommodation, one of the major reasons for the development of presbyopia is the progressive sclerosis of the crystalline lens. However, both the ciliary muscle and the lens capsule stay active and elastic. Thus, the concept for regaining the deformation-ability of the crystalline lens is to create microincisions inside lens tissue to achieve gliding planes.


METHODS
For the preparation of the microincisions, near-infrared femtosecond laser pulses are used, generating laser-induced optical breakdowns. Different cutting patterns were performed, and the elasticity regain of the lenses were measured with Fisher's spinning test for thickness determination.


RESULTS
The creation of gliding planes inside lens tissue shows very good results in terms of increasing the deformation-ability. The optimization of laser parameters leads to a minimally invasive surgery with no remarkable side effects like residual gas bubbles. Furthermore, ex vivo elasticity measurements of untreated and treated pig lenses show an improvement in the flexibility of the lens. The deformation-ability increases up to 26% with a very low standard deviation (1.6%) and a high significance (p < 0.05).


CONCLUSIONS
Generating particular cutting patterns inside lens tissue can increase the deformation-ability of the crystalline lens. Thus, it might be one possible way to treat presbyopia.
Ripken
Tammo
T
Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany. t.ripken@lzh.de
Oberheide
Uwe
U
Fromm
Michael
M
Schumacher
Silvia
S
Gerten
Georg
G
Lubatschowski
Holger
H
D000065:Accommodation, Ocular / Q000502:physiology*; D000818:Animals; D004548:Elasticity; D053685:Laser Therapy; D007908:Lens, Crystalline / Q000473:pathology / Q000601:surgery*; D011305:Presbyopia / Q000503:physiopathology / Q000601:surgery*; D013552:Swine