Ultraviolet femtosecond laser creation of corneal flap.

Purpose: To study parameters for ocular femtosecond laser surgery in terms of process efficiency and safety aspects using ultraviolet (UV) femtosecond laser pulses.

Methods: Studies on corneal surgery and flap processing on enucleated porcine eyes were performed using a newly developed ytterbium-doped gain media laser source. Ultraviolet femtosecond laser pulses centered at a wavelength of 345 nm and working at a repetition rate of 100 kHz were generated by the third harmonics of the 1035-nm fundamental wavelength.

Results: Flaps with a diameter of 6 mm and a thickness of 100 microm were created in less than 2 minutes with low energy pulses. Transmissions and spectral measurements were performed during flap processing. Less than 2% UV radiation reaches the retina during corneal flap processing. A detectable transmittance towards the retina of visible light centered on 440 nm was found for UV pulses.

Conclusions: Ultraviolet corneal refractive surgery is a novel procedure and has the potential to be an alternative to infrared refractive surgery considering safety aspects.