Samantha M Bradford1, Donald J Brown1, Tibor Juhasz1, Eric Mikula1, James V Jester2. 1. From the Department of Biomedical Engineering (Bradford, Brown, Juhasz, Jester) and the Department of Ophthalmology (Brown, Juhasz, Mikula, Jester), University of California, Irvine, California, USA. 2. From the Department of Biomedical Engineering (Bradford, Brown, Juhasz, Jester) and the Department of Ophthalmology (Brown, Juhasz, Mikula, Jester), University of California, Irvine, California, USA. Electronic address: jjester@uci.edu.
Abstract
PURPOSE: To determine whether riboflavin-induced collagen crosslinking (CXL) could be precisely achieved in the corneal stroma of ex vivo rabbit eyes using nonlinear optical excitation with a low numerical aperture lens and enlarged focal volume. SETTING: Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA. DESIGN: Experimental study. METHODS: The corneal epithelium was removed and the corneas were soaked in 0.5% riboflavin solution. Using a 0.1 numerical aperture objective, a theoretical excitation volume of 150 μm × 3 μm was generated using 1 W of 760 nm femtosecond laser light and raster scanned with 4.4 μm line separation at varying effective speeds over a 4.50 mm × 2.25 mm area. Corneal sections were examined for collagen autofluorescence. RESULTS: Collagen autofluorescence was enhanced 2.9 times compared with ultraviolet-A (UVA) CXL. Also, increasing speed was linearly associated with decreasing autofluorescence intensity. The slowest speed of 2.69 mm/s showed a mean of 182.97 μm ± 52.35 (SD) long autofluorescent scan lines axially in the central cornea compared with 147.84 ± 4.35 μm for UVA CXL. CONCLUSIONS: Decreasing dwell time was linearly associated with decreasing autofluorescence intensity, approaching that of UVA CXL at a speed of 8.9 mm/s. Using an effective speed of 8.9 mm/s, nonlinear optical CXL could be achieved over a 3.0 mm diameter area in fewer than 4 minutes. Further development of nonlinear optical CXL might result in safer, faster, and more effective CXL treatments. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.
PURPOSE: To determine whether riboflavin-induced collagen crosslinking (CXL) could be precisely achieved in the corneal stroma of ex vivo rabbit eyes using nonlinear optical excitation with a low numerical aperture lens and enlarged focal volume. SETTING: Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA. DESIGN: Experimental study. METHODS: The corneal epithelium was removed and the corneas were soaked in 0.5% riboflavin solution. Using a 0.1 numerical aperture objective, a theoretical excitation volume of 150 μm × 3 μm was generated using 1 W of 760 nm femtosecond laser light and raster scanned with 4.4 μm line separation at varying effective speeds over a 4.50 mm × 2.25 mm area. Corneal sections were examined for collagen autofluorescence. RESULTS: Collagen autofluorescence was enhanced 2.9 times compared with ultraviolet-A (UVA) CXL. Also, increasing speed was linearly associated with decreasing autofluorescence intensity. The slowest speed of 2.69 mm/s showed a mean of 182.97 μm ± 52.35 (SD) long autofluorescent scan lines axially in the central cornea compared with 147.84 ± 4.35 μm for UVA CXL. CONCLUSIONS: Decreasing dwell time was linearly associated with decreasing autofluorescence intensity, approaching that of UVA CXL at a speed of 8.9 mm/s. Using an effective speed of 8.9 mm/s, nonlinear optical CXL could be achieved over a 3.0 mm diameter area in fewer than 4 minutes. Further development of nonlinear optical CXL might result in safer, faster, and more effective CXL treatments. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.
Authors: Moritz Winkler; Dongyul Chai; Shelsea Kriling; Chyong Jy Nien; Donald J Brown; Bryan Jester; Tibor Juhasz; James V Jester Journal: Invest Ophthalmol Vis Sci Date: 2011-11-11 Impact factor: 4.799
Authors: Naoyuki Morishige; Andrew J Wahlert; M Cristina Kenney; Donald J Brown; Koji Kawamoto; Tai-Ichiro Chikama; Teruo Nishida; James V Jester Journal: Invest Ophthalmol Vis Sci Date: 2007-03 Impact factor: 4.799
Authors: Samantha M Bradford; Eric R Mikula; Dongyul Chai; Donald J Brown; Tibor Juhasz; James V Jester Journal: Biomed Opt Express Date: 2017-09-29 Impact factor: 3.732
Authors: Samantha Bradford; Eric Mikula; Yilu Xie; Tibor Juhasz; Donald J Brown; James V Jester Journal: Transl Vis Sci Technol Date: 2020-05-11 Impact factor: 3.283
Authors: Samantha Bradford; Eric Mikula; Sun Woong Kim; Yilu Xie; Tibor Juhasz; Donald J Brown; James V Jester Journal: Transl Vis Sci Technol Date: 2019-12-16 Impact factor: 3.283