Nonlinear optical corneal collagen crosslinking of ex vivo rabbit eyes

作者：Bradford Samantha M; Brown Donald J; Juhasz Tibor; Mikula Eric; Jester James V^*

来源：Journal of Cataract and Refractive Surgery, 2016, 42(11): 1660-1665.

DOI：10.1016/j.jcrs.2016.06.040

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 gm x 3 mu m was generated using 1 W of 760 nm femtosecond laser light and raster scanned with 4.4 mu m line separation at varying effective speeds over a 4.50 mm x 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 mu m +/- 52.35 (SD) long autofluorescent scan lines axially in the central cornea compared with 147.84 +/- 4.35 mu m 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.

• 出版日期2016-11