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Scattering properties of ultrafast laser-induced refractive index shaping lenticular structures in hydrogels

Published

Author(s)

Kaitlin Wozniak, Thomas Germer, Sam Butler, Daniel Brooks, Krystel Huxlin, Jonathan D. Ellis

Abstract

We present measurements of light scatter induced by a new ultrafast laser technique being developed for laser refractive correction in transparent ophthalmic materials such as cornea, contact lenses, and/or intraocular lenses. In this new technique, called Intra- tissue Refractive Index Shaping (IRIS), a 405 nm femtosecond laser is focused and scanned below the corneal surface, inducing a spatially-varying refractive index change that corrects vision errors. In contrast with traditional laser correction techniques, such as laser in-situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), IRIS does not operate via photoablation, but rather changes the refractive index of transparent materials such as cornea and hydrogels. A concern with any laser eye correction technique is additional scatter induced by the process, which can adversely affect vision, especially at night. The goal of this investigation is to identify sources of scatter induced by IRIS and to mitigate possible effects on visual performance in ophthalmic applications. Preliminary light scattering measurements on patterns written into hydrogel showed four sources of scatter, differentiated by distinct behaviors: (1) scattering from stitching errors, resulting from adjacent scanning fields not being aligned to one another; (2) scattering from scanned lines; (3) diffraction from Fresnel zone discontinuities, and (4) long-period variations in the scans that created distinct diffraction peaks, likely due to inconsistent line spacing in the writing instrument. By knowing the nature of these different scattering errors, it will now be possible to modify and optimize the design of IRIS structures to mitigate potential deficits in visual performance in human clinical trials.
Proceedings Title
Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XVIII
Volume
10522
Conference Dates
January 28-30, 2018
Conference Location
San Francisco, CA, US

Keywords

femtosecond, hydrogel, ophthalmic, photo-modification, scatter, vision correction

Citation

Wozniak, K. , Germer, T. , Butler, S. , Brooks, D. , Huxlin, K. and Ellis, J. (2018), Scattering properties of ultrafast laser-induced refractive index shaping lenticular structures in hydrogels, Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XVIII, San Francisco, CA, US, [online], https://doi.org/10.1117/12.2290204, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=925030 (Accessed April 19, 2024)
Created February 18, 2018, Updated January 4, 2022