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Proceedings Paper

Polymers for refractive index change in intraocular lenses: a novel approach for photo-induced tuning of focal length
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Paper Abstract

Before an intraocular lens (IOL) is implanted during cataract surgery, biometric data of the patient's eye have to be determined to calculate the thickness and shape of the IOL. In particular the postoperative anterior chamber depth is an important parameter to predict the correct shape of the IOL. This value, however, cannot be measured without significant uncertainities. We present a solution to this problem, describe novel polymers suitable for IOLs which refractive indices can be changed non-invasively in a photo-induced process. The focal length can be modified by about 2 D, which is sufficient to achive ideal acuteness of vision for almost all patients with implanted IOLs. The change in refractive index is accomplished by linking or cleaving bonds between a sufficiently large number of side groups of the polymer main chain in a photoinduced cyloaddition or cycloreversion, respectively. The photochemical reaction can also be triggered by a two-photon process (TPA) using a pulsed laser system, i.e. the energy required for bond breaking is provided by two photons in the visible range. Light in the UV as well as the visible range of the spectrum cannot induce undesired changes of the refractive index owing to the strong UV-absorption of the cornea and photon densities much too low for TPA, respectively. Due to the excellent spatial resolution that can be achieved with two-photon processes not only modification of the refractive index of the entire lens but also selectively in well defined areas is possible enabling the correction for aberrations such as astigmatism.

Paper Details

Date Published: 7 March 2006
PDF: 9 pages
Proc. SPIE 6138, Ophthalmic Technologies XVI, 61381D (7 March 2006); doi: 10.1117/12.646214
Show Author Affiliations
Jens Träger, Univ. of Marburg (Germany)
Hee-Cheol Kim, Univ. of Marburg (Germany)
Norbert Hampp, Univ. of Marburg (Germany)
Material Science Ctr. Marburg (Germany)

Published in SPIE Proceedings Vol. 6138:
Ophthalmic Technologies XVI
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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