Mini-invasive corneal surgery and imaging with femtosecond lasers

Abstract

Based on the transparency of corneal tissue and on laser plasma mediated non-thermal tissue ablation, near infrared femtosecond lasers are promising tools for minimally invasive intrastromal refractive surgery. Femtosecond lasers also enable novel nonlinear optical imaging methods like second harmonic corneal imaging. The microscopic effects of femtosecond laser intrastromal surgery were successfully visualized by using second harmonic corneal imaging with diffraction limited resolution, strong imaging contrast and large sensing depth, without requiring tissue fixation or sectioning. The performance of femtosecond laser intrastromal surgery proved to be precise, repeatable and predictable. It might be possible to integrate both surgical and probing functions into a single femtosecond laser system.

Simulation of the temperature increase in human cadaver retina during direct illumination by 150-kHz femtosecond laser pulses

“…[4][5][6][7][8] Due to the advantage of the enhanced precision and minimized collateral tissue effects, femtosecond lasers have displaced the mechanical microkeratome as the dominant tool for LASIK flap creation in the US over the past decade. [9][10][11][12][13][14][15] Diode pumped all-solid-state femtosecond lasers are now also commonly used to perform corneal transplants [16][17][18] or being investigated to perform additional procedures, such as fs-lentotomy. [19][20][21] The iFS advanced femtosecond laser (AMO Inc., Santa Ana, California) is the most popular laser machine on the US market.…”

Femtosecond laser corneal ablation threshold: Dependence on tissue depth and laser pulse width

“…Over the last decade, the field of femtosecond eye surgery has expanded rapidly, supporting the advantage of combined high ablation precision and minimized collateral tissue effects [1][2][3][4]. One of the most promising applications for femtosecond laser eye surgery has been corneal surgery [5,6], where the high-pressure laser plasma nonthermally dissociates the dense corneal tissue thereby enabling lamellar cornea procedures with minimized side effects [7].…”

Two-photon excited autofluorescence imaging of human retinal pigment epithelial cells

“…Recently, the fine structures of the collagen fibrils in cornea and sclera have been successfully resolved with second harmonic imaging microscopy. [17][18][19][20] However, to the best of our knowledge, there are no reports of two-photon excited fluorescence ͑TPEF͒ imaging of individual human RPE cells with relevant discussions of the feasibility of a two-photon laser scanning ophthalmoscope.…”