fs-Laser induced elasticity changes to improve presbyopic lens accommodation

Ripken, Tammo; Oberheide, Uwe; Fromm, Michael; Schumacher, Silvia; Gerten, Georg; Lubatschowski, Holger

doi:10.1007/s00417-007-0699-x

Cited by 66 publications

(48 citation statements)

References 20 publications

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“…Previous research by Hollman et al (2003) ultrasonically observed an increase in human lens deformation by radial stretching after LIOB treatment over a large grid using the same Nd:glass laser as the present study. Finally, Ripken et al (2005) have created microcuts using a femtosecond Ti:Sapphire laser within porcine lenses and measured an increased deformability during lens spinning measurements.…”

Section: Discussionmentioning

confidence: 99%

Mapping age-related elasticity changes in porcine lenses using bubble-based acoustic radiation force

Erpelding

Hollman

O’Donnell

2007

Experimental Eye Research

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Bubble-based acoustic radiation force aims to measure highly localized tissue viscoelastic properties. In the current investigation, acoustic radiation force was applied to laser-induced bubbles to measure age-related changes in the spatial distribution of elastic properties within in vitro porcine lenses. A potential in vivo technique to map lens elasticity is crucial to understanding the onset of presbyopia and develop new treatment options. Bubble-based acoustic radiation force was investigated as a technique to measure the spatial elasticity distribution of the lens in its natural state without disrupting the lens capsule.Laser-induced optical breakdown (LIOB) generated microbubbles in a straight line across the equatorial plane of explanted porcine lenses with 1 mm lateral spacing. Optical breakdown occurs when sufficiently high threshold fluence is attained at the focus of femtosecond pulsed lasers, inducing plasma formation and bubble generation. A two-element confocal ultrasonic transducer applied 6.5 ms acoustic radiation force-chirp bursts with the 1.5 MHz outer element while monitoring bubble position within the lens using pulse-echoes with the 7.44 MHz inner element. A crosscorrelation method was used to measure bubble displacements and determine exponential time constants of the temporal responses. Maximum bubble displacements are inversely proportional to the local Young's modulus, while time constants are indicative of viscoelastic properties.The apparent spatial elasticity distributions in 41 porcine lenses, ranging from 4 months to 5 years in age, were measured using bubble-based acoustic radiation force. Bubble displacements decrease closer to the porcine lens center, suggesting that the nucleus is stiffer than the cortex. Bubble displacements decrease with increasing lens age, suggesting that porcine lenses become stiffer with age. Bubble-based acoustic radiation force may be well-suited as a potential in vivo technique to spatially map elastic properties of the lens and guide therapeutic procedures aimed at restoring accommodation.

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Section: Discussionmentioning

confidence: 99%

Mapping age-related elasticity changes in porcine lenses using bubble-based acoustic radiation force

Erpelding

Hollman

O’Donnell

2007

Experimental Eye Research

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“…There are a number of different treatments under development, including scleral implants, corneal surgeries, pharmacological interventions to soften the lens, artificial intraocular lens implants, and laser surgery of the lens [74]. Lenticular surgery aims to restore flexibility by breaking the hardened-tissue structures and creating gliding planes of tissue [75]. Previous surgical attempts with nanosecond or picosecond lasers left behind residual gas bubbles, but femtosecond laser ablation of the lens yields lesions with bubbles that resolve with time [76].…”

Section: Presbyopiamentioning

confidence: 99%

Surgical applications of femtosecond lasers

Chung¹,

Mazur

2009

Journal of Biophotonics

231

136

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Femtosecond laser ablation permits non‐invasive surgeries in the bulk of a sample with submicrometer resolution. We briefly review the history of optical surgery techniques and the experimental background of femtosecond laser ablation. Next, we present several clinical applications, including dental surgery and eye surgery. We then summarize research applications, encompassing cell and tissue studies, research on C. elegans, and studies in zebrafish. We conclude by discussing future trends of femtosecond laser systems and some possible application directions. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…In further investigations of the treatment of enucleated porcine and human autopsy lenses, Ripken et al [10] showed that cutting a 3D pattern inside the lens tissue with femtosecond laser pulses can increase the mechanical flexibility of the lens (Figure 1). Moreover, the flexibility of the lens increased depending on the particular cutting pattern [10,11].…”

Section: Introductionmentioning

confidence: 97%

Femtosecond lentotomy: generating gliding planes inside the crystalline lens to regain accommodation ability

Lubatschowski

Schumacher

Fromm

et al. 2010

Journal of Biophotonics

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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.

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fs-Laser induced elasticity changes to improve presbyopic lens accommodation

Abstract: 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.

Cited by 66 publications

References 20 publications

Mapping age-related elasticity changes in porcine lenses using bubble-based acoustic radiation force

Mapping age-related elasticity changes in porcine lenses using bubble-based acoustic radiation force

Surgical applications of femtosecond lasers

Femtosecond lentotomy: generating gliding planes inside the crystalline lens to regain accommodation ability

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