Abstract

DO.14.08

In vitro femtosecond laser ablation and imaging of ocular tissues

Matthias Hild1, Berthold Seitz1, Matthias H. J. Krause1, Elena Khurieva1, Sergey Toropygin2, Iris Riemann3, Karsten König4
1Klinik für Augenheilkunde, Universitätskliniken des Saarlandes, Homburg/Saar; 2Tver State Medical Academy, Tver, Russia; 3AG Biomedizinische Optik, Fraunhofer Institut für Biomedizinische Technik, St. Ingbert; 4Fachrichtung Mechatronik, Naturwissenschaftlich-Technische Fakultät II, Universität des Saarlandes, Saarbrücken

Objective
Femtosecond (fs) lasers offer high precision with good functional results in refractive surgery. Non-amplified fs lasers are established in imaging and ablation of cells and tissues. We report on imaging and tissue ablation of the anterior and posterior segment of the eye.
Methods
A non-amplified fs laser (wavelength 800 nm,  pulse width 160 - 190 fs) was coupled into a laser scanning microscope. The laser beam was focussed at pulse energies of 0.1 - 2.0 nJ into specimens of retina, lens capsule and epiretinal membrane). Autofluorescence or reflection was detected immediately before and after laser irradiation by irradiation of the probes by the identical laser device at low pulse energies of 0.01 - 0.1 nJ. Specimens were transferred to histology and electron microscopy.
Results
With pulse energies in the low nJ range, retinal nerve fiber layer, posterior lens capsule and epiretinal membranes could selectively be imaged an ´cut´ . A lesion width below 1 µm in lens capsule and epiretinal membranes, and below 3 µm in the nerve fiber layer was obtained. In retinal vessels, blood clots and foreign material could be ablated without damaging the vessel walls.
Conclusions
Non-amplified femtosecond lasers allow selective in vitro imaging and ablation of ocular tissues.

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