The Feasibility of refractive surgery with ultrashort laser pulses in the fs-regime was studied. The Experiments were performed with an Erbium fiberlaser oscillator, which was amplified by means of chirped pulse amplification in a Titanium-Sapphire regenerative amplifier. With this system pulse durations of 180 fs and pulse energies of up to some hundred (mu) J were possible. The photodisruption was performed in corneal tissue in order to create corneal incisions and lamellars. Surface quality and thermal damages of the cuts inside the tissue were studied with the help of micromorphological analysis, such as scanning electron microscopy (SEM) and histological sections. High level precision along with minimal thermal damage could be observed. Saline solution as a model substance was used for studying side effects as bubble formation and pressure transients. The pressure measurements were performed using broadband acoustic transducers. Gas bubbles were analyzed with respect to formation, dynamics, interaction and composition of different gas constituents with the help of flash photography and gas chromatography. The results demonstrate the minimal invasive treatment of corneal stroma by fs-photodisruption. Studies of secondary effects indicate, that additional processes have to be considered.

Date Published: 7 June 2000
PDF: 11 pages
Proc. SPIE 3908, Ophthalmic Technologies X, (7 June 2000); doi: 10.1117/12.387518

Published in SPIE Proceedings Vol. 3908:
Ophthalmic Technologies X
Pascal O. Rol; Karen Margaret Joos M.D.; Fabrice Manns, Editor(s)