Lentotomy

Background: Research and awareness on refractive solutions for presbyopia, commonly known as the "Curse of the 40's," is essential as a large population in the world suffer from vision impairments. Population-based surveys have shown that one billion people in the world are in presbyopic age. Purpose: Many structural and physiological changes occur in the eye with the onset of presbyopia, including the decrease in amplitude of accommodation. At present, various static and dynamic techniques have been attempted to give presbyopes good vision at near-, intermediate-, and far-viewing distances...

PURPOSE: The use of a femtosecond laser to form planes of cavitation bubbles within the ocular lens has been proposed as a potential treatment for presbyopia. The intended purpose of these planes of cavitation bubbles (referred to in this paper as 'cutting planes') is to increase the compliance of the lens, with a consequential increase in the amplitude of accommodation. The current paper describes a computational modelling study, based on three-dimensional finite element analysis, to investigate the relationship between the geometric arrangement of the cutting planes and the resulting improvement in lens accommodation performance...

PURPOSE: According to Helmholtz, accommodation is based on the flexibility of the crystalline lens, which decreases with age, causing presbyopia. With femtosecond (fs)-lentotomy treatment, it is possible to restore the flexibility of presbyopic lenses. The efficiency of the treatment can be systematically evaluated using the finite element method based on experimental data. The purpose of this study was to quantify the shape change of ex vivo lenses in different accommodation states according to the fs-lentotomy treatment...

BACKGROUND AND OBJECTIVE: The optimized parameters of femtosecond (fs) lentotomy, an innovative strategy for presbyopia, have been further discussed regarding the safety of the procedure for eyeballs. This article's aim was to prove the safety and feasibility of the fs lentotomy procedure with 50-fs laser pulses. STUDY DESIGN/MATERIALS AND METHODS: This was an experimental study in which the safety of fs lentotomy by optical measurement was tested. The experiment was performed on 49 porcine crystalline lenses by 50-fs laser pulses at a central wavelength of 800 nm and scanning focusing optics with a numerical aperture (NA) of 0...

Based on Helmholtz Theory for accommodation the increasing sclerosis of lens nucleus and cortex is the main cause for the developments of presbyopia. Existing therapies, however, do not reverse the stiffness of the crystalline lens and thus do not regain real accommodation ability. A new approach to restore the flexibility of the lens could be realized by photodisruption using ultrafast laser pulses. This process, known as fs-lentotomy, was used to create micro-incisions which act as gliding planes inside the crystalline lens without opening the eye globe...

Based on the Helmholtz theory for accommodation, increasing sclerosis of the lens nucleus and cortex is the main cause for the development of presbyopia. Existing therapies, however, do not reverse the stiffness of the crystalline lens and thus do not regain real accommodation ability. A new approach to restore the flexibility of the lens has been realised by utilising the non-linear interaction of ultrafast laser pulses with transparent tissue, the so-called photodisruption. This process has been used to create micro-incisions which act as gliding planes inside the crystalline lens without opening the eye globe...

PURPOSE: According to the Helmholtz theory of accommodation, one major cause of the development of presbyopia is the increasing sclerosis of the crystalline lens. One concept for regaining the elasticity of the sclerosing lens is intralenticular treatment by femtosecond laser pulses. METHODS: The feasibility of applying and imaging in vivo microincisions by femtosecond laser pulses was evaluated in five rabbit lenses with a new high repetition rate (100 kHz) femtosecond laser unit...

BACKGROUND: Ultrashort (femtosecond) laser pulses can generate precise cuts in biological tissue without damaging the surface. The application of femtosecond laser technology at the lens was evaluated with respect to a possible treatment of presbyopia. MATERIALS AND METHODS: Femtosecond laser lentotomy was performed on 150 pig lenses in vitro. Cutting geometry and laser settings were optimized to generate smooth cuts with a minimum of produced gas bubbles. Four rabbit lenses were treated afterwards in vivo and were controlled for 3 months post-treatment...