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Microscope study regarding the chemical basis for alteration of an intraocular lens using a femtosecond laser

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Session Details

Session Title: LASIK and Imaging

Session Date/Time: Tuesday 10/10/2017 | 14:00-15:20

Paper Time: 14:43

Venue: Room 4.1

First Author: : J.Bille GERMANY

Co Author(s): :    R. Sahler   D. Schanzlin                 

Abstract Details


The Refractive Index Shaping (RIS) treatment of an intraocular lens uses a femtosecond laser to change the hydrophilicity of the targeted area, which allows a change in the refractive index, e.g. a negative refractive index change, in the laser treated areas. This effect in combination with a two dimensional scan pattern allows the creation of a refractive or diffractive lens inside the material. It is the purpose of the microscope study to investigate the chemical and physical changes in an intraocular lens which are caused by the exposure of the acrylic material to the femtosecond laser.


The microscope study was performed in a collaborative effort in the laboratories of Perfect Lens, LLC, Irvine, CA, USA, German Cancer Research Center (DKFZ), Germany, Department of Physical Chemistry, University of Heidelberg, Germany, and Leica Microsystems CMS GmbH, Mannheim, Germany.


Three different microscope setups have been used for the study: Laser Induced Fluorescence (LIF) microscopy, Raman microscopy and Coherent Anti-Stokes Raman Scattering (CARS) microscopy. For LIF-microscopy, a STED (Stimulated Emission Depletion) microscope was utilized. Raman spectra were recorded on a commercial HORIBA XploRA PLUS Raman Microscop. CARS images were acquired with a Leica TCS SP8 CARS system (Leica Microsystems, Mannheim, Germany). Various hydrophilic and hydrophobic intraocular lens materials were studied. Each microscope is being used to identify exactly what molecular changes occur upon exposure of the polymeric material to the light of the femtosecond laser.


The polar bonds within the acrylic material are altered such that the material absorbs additional water, in areas exposed to a femtosecond laser, thus providing the chemical basis for a hydrophilicity based negative refractive index change, facilitating the creation of a Refractive Index Shaping (RIS)- lens. The newly formed functional groups, e.g. amines and carboxylic acids, are strongly hydrophilic. In three different polymeric materials, fluorophores with identical spectral signatures were detected. Thus, photo-induced hydrolysis results in rearrangements of chemical bonds, within the polymer molecule, respectively the UV-absorber molecule, preserving the integrity of the polymeric material.


A new method for modifying the refractive index of polymeric materials has been developed, wherein existing molecules within a polymeric material become hydrophilic inside an intraocular lens (IOL). This change in hydrophilicity occurs when the polymeric material is immersed in an aqueous medium, and is exposed to femtosecond laser radiation. The aqueous medium and the femtosecond laser radiation provide the chemical basis for the hydrophilicity based refractive index change. Photo-induced hydrolysis results in rearrangements of chemical bonds, essentially within the UV-absorber molecule, preserving the integrity of polymeric material. Hydrophobic as well as hydrophilic acrylic materials can be affected.

Financial Disclosure:

gains financially from product or procedure presented, travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, is employed by a forNONEprofit company with an interest in the subject of the presentation, has significant investment interest in a company producing, developing or supplying product or procedure presented

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