Laser safety aspects for refractive eye surgery with femtosecond laser pulses

Harzic, Ronan Le; Bückle, Rainer; Wüllner, Christian; Donitzky, Christof; König, Karsten

doi:10.1016/j.mla.2005.07.008

Cited by 20 publications

(8 citation statements)

References 20 publications

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“…Preliminary estimates suggest that 50 to 60% of laser energy passes beyond the cornea with a potential hazard to the retina and iris. [25][26][27] A safety assessment can provide an analysis of exposure relative to established exposure limits. ANSI Z136.1-2007 series provides internationally accepted exposure limits.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2011

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Abstract.We have developed a two-dimensional computer model to predict the temperature increase of the retina during femtosecond corneal laser flap cutting. Simulating a typical clinical setting for 150-kHz iFS advanced femtosecond laser (0.8-to 1-μJ laser pulse energy and 15-s procedure time at a laser wavelength of 1053 nm), the temperature increase is 0.2• C. Calculated temperature profiles show good agreement with data obtained from ex vivo experiments using human cadaver retina. Simulation results obtained for different commercial femtosecond lasers indicate that during the laser in situ keratomileusis procedure the temperature increase of the retina is insufficient to induce damage. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Section: Introductionmentioning

confidence: 99%

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

et al. 2011

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“…The large impact that this advanced technology is having on the medical field is exemplified by its use in several of the most commonly performed surgical procedures in the world, specifically, LASIK, cataract surgery, and corneal transplantation [7][8][9][10][11][12][13]. In order to achieve optical breakdown, the predominant tissue cutting mechanism [14,15], FSLs must generate very high intensities, which can also generate nonlinear optical effects (NOEs) such as second and third harmonic generation (SHG and THG, respectively) [16,17]. NOEs cause a modification of the optical properties of a susceptible material due to an intense optical field, often generated by ultrashort pulsed lasers [18,19].…”

Section: Introductionmentioning

confidence: 99%

“…As nonlinear optical effects such as harmonic generation are greatly dependent on laser intensity, we believe that an investigation of the relationships between HG elicited by clinically important FSL parameters at these energy levels is warranted. Other nonlinear effects occurring also at significantly lower intensities, such as self-focusing and filamentation, have recently been studied using therapeutic FSL parameters [16,17,30]. SHG and THG have even been reported during photodisruption in corneal tissue [16,17,31], but no investigation to our knowledge has examined the relationship between laser parameters and HG characteristics at these energy levels.…”

Section: Introductionmentioning

confidence: 99%

Effect of therapeutic femtosecond laser pulse energy, repetition rate, and numerical aperture on laser-induced second and third harmonic generation in corneal tissue

Calhoun

Ilev

2015

Lasers Med Sci

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Clinical therapy incorporating femtosecond laser (FSL) devices is a quickly growing field in modern biomedical technology due to their precision and ability to generate therapeutic effects with substantially less laser pulse energy. FSLs have the potential to produce nonlinear optical effects such as harmonic generation (HG), especially in tissues with significant nonlinear susceptibilities such as the cornea. HG in corneal tissue has been demonstrated in nonlinear harmonic microscopy using low-power FSLs. Furthermore, the wavelength ranges of harmonic spectral emissions generated in corneal tissues are known to be phototoxic above certain intensities. We have investigated how the critical FSL parameters pulse energy, pulse repetition rate, and numerical aperture influence both second (SHG) and third harmonic generation (THG) in corneal tissue. Experimental results demonstrated corresponding increases in HG intensity with increasing repetition rate and numerical aperture. HG duration decreased with increasing repetition rate and pulse energy. The data also demonstrated a significant difference in HG between FSL parameters representing the two most common classes of FSL therapeutic devices.

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“…Preliminary estimates suggest that almost half of laser energy passes beyond the cornea with potential effects on the retina and iris. [19][20][21] The temperature increase in human cadaver retina was investigated via ex vivo experiments and simulation by our group previously. 19 To study the temperature increase of the iris is also reasonable, since during the LASIK surgery the iris is closer to the focus of the laser beam than the retina.…”

Section: Introductionmentioning

confidence: 99%

Finite element model of the temperature increase in excised porcine cadaver iris during direct illumination by femtosecond laser pulses

2012

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Abstract. In order to model the thermal effect of laser exposure of the iris during laser corneal surgery, we simulated the temperature increase in porcine cadaver iris. The simulation data for the 60 kHz FS60 Laser showed that the temperature increased up to 1.23°C and 2.45°C (at laser pulse energy 1 and 2 μJ, respectively) by the 24 second procedure time. Calculated temperature profiles show good agreement with data obtained from ex vivo experiments using porcine cadaver iris. Simulation results of different types of femtosecond lasers indicate that the Laser in situ keratomileusis procedure does not present a safety hazard to the iris.

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Laser safety aspects for refractive eye surgery with femtosecond laser pulses

Cited by 20 publications

References 20 publications

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

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

Effect of therapeutic femtosecond laser pulse energy, repetition rate, and numerical aperture on laser-induced second and third harmonic generation in corneal tissue

Finite element model of the temperature increase in excised porcine cadaver iris during direct illumination by femtosecond laser pulses

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