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Femtosecond laser enables detailed imaging of corneal structures
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CHICAGO — Femtosecond laser imaging can provide insight into corneal biomechanics, a researcher said here.
"There's something more that you can do with femotsecond lasers besides cutting," James V. Jester, PhD, said during Refractive Subspecialty Day preceding the joint meeting of the American Academy of Ophthalmology and the Middle East Africa Council of Ophthalmology.
Dr. Jester outlined findings using a femtosecond laser to produce optical signals including 2-photon excited fluorescence and second-harmonic generation.
"These types of signals can be generated from non-symmetric materials, particularly collagen, in which they can absorb two photons of light and emit a single photon of light," Dr. Jester said. "Collagen, of course, is the dominant type of structure in the eye that can generate these types of signals."
The imaging modality enables imaging of internal corneal structures with high axial and lateral resolution.
Researchers used the new approach to observe collagen fibers in the Bowman's layer and the anterior layers of the cornea. They aimed to gauge the spatial, three-dimensional organization of collagen and relate that to the biomechanical properties of the anterior and posterior cornea, Dr. Jester said.
Dr. Jester said that researchers have hypothesized that the intertwining of collagen fibers stiffens the anterior cornea, and controls corneal curvature and shape.
Further study is needed, he said.
This technology will likely shed some much-needed light on the relationships between corneal structure, tissue mechanics and function. Thanks to Drs. Jester, Winkler, Chai, et al, we have a powerful new tool to examine the cornea. Using this technology, the authors have already uncovered previously unknown corneal features, such as the extensive branching of corneal collagen fibers in the anterior cornea. This talented team is gauging the spatial, three-dimensional organization of the collagen fibers and relating that to the biomechanical properties of the anterior and posterior cornea. This work may someday allow us to predict who will get keratoconus or ectasia after LASIK when the rest of the exam is completely normal.
– Marguerite B. McDonald, MD
OSN
Refractive Surgery Board Member