Laser intrastromal ablation for refractive surgery bas been accomplished with ultrashoit-pulse lasers operating at multi-kHz pulse repetition frequencies to produce optical breakdown and plasma formation to cut within the corneal stroma. The focused laser beam can move in a controlled pattern over a desired corneal area to produce a clean flap for laser refractive surgery. To determine the safety of exposure of other ocular structures such as the lens and retina, a determination of the irradiance behind the optical plasma are required. Plasma shielding absorbs (and scatters) almost all of the incident energy in this surgical application and optical breakdown and optical plasma generation produce tissue vaporization, allowing only a small fraction of the incident energy to be transmitted through the plasma. In this safety study, measurements were performed at the retinal plane in a simulated eye and a retinal simulant was used to demonstrate the safety of the retinal exposure for a sub-nanosecond laser. It is shown that this procedure does not pose a hazard to other ocular tissues.
REFERENCES
1.
American Conference of Governmental Industrial Hygienists (ACGIH)
(2001
), TLV’s, Threshold Limit Values and Biological Exposure Indices for 2002
, American Conference of Governmental Industrial Hygienists
, Cincinnati, OH
.2.
American National Standards Institute (ANSI, 2000)
, American National Standard for Safe Use of Lasers
, ANSI Z136.1-2000, Orlando
, Laser Institute of America
.3.
Bille
J.F.
, Hamer
C.F.H.
, Loesel
F.H.
, (Eds.) (2002
) Aberration-Free Refractive Surgery
, Berlin
, Springer-Verlag
.4.
Brown
DB
, O’Brien
WJ
, Schultz
RO
(1994
). The mechanism of ablation of corneal tissue by the neodymium doped yttrium-Hthium-fhroride picosecond laser
. Cornea
. 13
(6
):479
–86
.5.
Cain
, C. P.
, Toth
, C. A.
, DiCarlo
, C. D.
, Stein
, C. D.
, Noojin
, G. D.
, Stolarski
, D. J.
, Roach
, W. P.
, (1995
) Visible Retinal Lesions from Ultrashort laser pulses in the primate eye
, Invest Ophthal Visual Sci
, 36
(5
):879
–888
6.
Cain
, C. P.
, C. A.
Toth
, R. J.
Thomas
, G. D.
Noojin
, V.
Carothers
, D. J.
Stolarski
, B. A.
Rockwell
, (2000
), Comparison of macular versus paramacular retinal sensitivity to femtosecond laser pulses
, J. Biomed. Optics
, 5
(3
):315
–320
.7.
Cain
, C.P.
Cain
, C. P.
, C. A.
Toth
, G. D.
Noojin
D. J.
Stolarski
, R. J.
Thomas
& B. A.
Rockwell
, (2002
), Visible lesion thresholds from multiple pulse near infrared ultra short laser pulses in the retina”
Health Phys
82
(6
); 855
–862
.8.
Cain
, C. P.
, C. A.
Toth
, G. D.
Noojin
, D. J.
Stolarski
, S.
Cora
and B. A.
Rockwell
, (2002
), Visible lesion threshold dependence on retinal spot size for femtosecond laser pulses
, J. Laser Appl.
13
(3
);125
–131
.9.
Condon
, P.I.
, Mulhern
M.
, Fulcher
T.
, Foley-Nolen
A.
, O’Keefe
M.
, (1997
) Laser intrastromal keratomileusis for high myopia and myopia astigmatism
. Br J Ophthalmol.
81
(3
):199
–206
.10.
Edelhauser
H.F.
(2000
) The resiliency of the corneal endothelium to refractive and intraocular surgery
. Cornea.
;19
(3
):263
–73
.11.
Huebscher
HJ
, Genth
U
, Seiler
T.
, (1996
) Determination of excimer laser ablation rate of the human cornea using in vivo Scheimpflug videography
. Invest Ophthalmol Vis Sci.
Jan;37
(1
):42
–6
.12.
International Commission on Non-Ionizing Radiation Protection
, (2000
), Revision of guidelines on limits of exposure to laser radiation of wavelengths between 400 run and 1.4 μm
, Health Physics
, 79
(4
):431
–440
.13.
International Commission on Non-Ionizing Radiation Protection
, (1997
), Guidelines on limits of exposure to broad-band incoherent optical radiation (0.38 to 3 μm)
, Health Physics
, 73
:539
–554
.14.
International Electrotechnical Commission (IEC)
, (2001
), Standard 60825-1.2-2001.15.
Juhasz
T
, Hu
XH
, Turi
L
, Bor
Z.
, (1994
), Dynamics of shock waves and cavitation bubbles generated by picosecond laser pulses in corneal tissue and water
. Lasers Surg Med.
;15
(1
):91
–8
.16.
Juhasz
T
, Kastie
G.A.
, Suarez
C.
, Bor
Z.
, and Bron
W.E.
, (1996
) Time-resolved observation of shock waves and cavitation bubbles generated by femtosecond laser pulses in corneal tissue and water
. Laser Surg. Med.
, 19
:23
.17.
Juhasz
T
, Loesel
F.H.
, Kurtz
R.M.
, Horvath
C.
, Bille
J.F.
, and Mouron
G.
, (1999
), Corneal refractive surgery with femtosecond lasers
. IEEE J Selected Topics Quant. Electron
. 5
(4
):902
–910
.18.
Loesel
F. H.
, Zickler
L.
, and Kessler
R.
, (2002
) Refractive surgical applications of ultrashort pulse lasers, in (Bille
J.F.
, Hamer
C.F.H.
, Loesel
F.H.
, Eds.) Aberration-Free Refractive Surgery
, Berlin
, Springer-Verlag
,.19.
Lubatschowski
H
, Maatz
G
, Heisterkamp
A
, Hetzel
U
, Drommer
W
, Welling
H
, Ertmer
W
, (2000
), Application of ultrashort laser pulses for intrastromal refractive surgery
.20.
Mainster
, M.A.
, Sliney
, D.H.
, Belcher
, C.D.
, III, and Buzney
, S.M.
, (1983
), Laser photodismptors, damage mechanisms, instrument design and safety
,” Ophthalmology
, 90
(8
):937
–944
.21.
Mellerio
, J.
, Capon
, M.R.C.
, Docchio
, F.
, Sliney
, D.H.
, and Rrafft
, K.
, (1988
), A new form of damage to PMMA intraocular lenses by Nd:YAG laser photodisruptors
, Eye
2
:376
–381
22.
D. J.
Payne
, R. A.
Hopkins
, B. G.
Eilert
, G. D.
Noojin
, D. J.
Stolarski
, R. J.
Thomas
, G. T.
Hengst
, P.
Kennedy
, and B. A.
Rockwell
, (1999
), Comparative Study of Laser Damage Threshold Energies in the Artificial Retina
,” Jour. of Biomed. Optics
4
, 337
–344
.23.
Quantock
AJ
, Juhasz
T
, Ito
M
, Assil
KK
, Schanzlin
DJ
, Krueger
R.R.
, (1996
) Ultrastructure of picosecond laser intrastromal photodisruption
. J Refract Surg
. 12
(5
):607
–12
.24.
Rockwell
, B.A.
, Roach
, W.P.
, Rogers
, M.E
, (1994
) Determination of self-focusing effects for light propagating in the eye, SPIE Proceedings (Laser-Tissue Interaction V
, 24-27 January 1994
, Los Angeles, CA
), 2134A
:2
–9
25.
Roach
, W.P.
, Johnson
, T.E.
, Rockwell
, B.A.
, (1999
). Proposed maximum permissible exposure limits for ultrashort laser pulses
, Health Physics
, 76
(4
):349
–354
.26.
Rockwell
, B.A.
, Hammer
, D.X.
, Hopkins
, R.A
Payne
, D. J.
, Toth
, C.A.
, Roach
, W. P.
, Draessel
, J. J.
Kennedy
, P. K.
Amnotte
, R. E.
Eilert
, B.
Phillips
, S.
Noojin
, G. D.
Stolarski
D. J.
and Cain
, C. P.
(1999
) Ultrashort laser pulse bioeffects and safety
, J Laser Appl
. 11
, 42
–44
.27.
Sliney
, D.H.
, (1983
) YAG laser safety, in YAG Laser Ophthalmic Microsurgery
(S.L.
Trokel
, Ed.), Appleton-Century-Crofts
, Norwalk
, pp. 67
–84
.28.
Sliney
, D.H.
, (1985
) Neodymium:YAG Laser Safety Considerations
, in [R. M.
Klapper
, Ed.] Neodymium:YAG Laser Microsurgery: Fundamental Principles and Clinical Applications
, Int. Opthal Clin.
, 23
(3
):151
–157
.29.
Sliney
, D.H.
, (1999
) Retinal injury from laser radiation
, Nonlinear Optics, Proceedings of First International Workshop on Optical Power Limiting
, Cannes, France
, 28 June - 1 July 1998
, (edited by Kajzar
, F.
) Gordon and Breach Science Publishers
, Channel Islands
, 21
(1-4
):1
–18
.30.
Sliney
D.H.
, Mellerio
J.
, Gabel
V.-P.
, and Schulmeister
K.
(2002
), What is the meaning of threshold in laser injury experiments? Implications for human exposure limits
, Health Physics
, 82
(3
):335
–347
.31.
Sliney
D. H.
and M. L.
Wolbarsht
(1980
) Safety with Lasers and Other Optical Sources
. New York
: Plenum Publishing Corp
.32.
US Food and Drug Administration (FDA)
, (1985
) Federal Laser Performance Standard, Title 21, Code of Federal Regulations, Subchapter J, Part 1040 [21CFR1040]
, Center for Devices and Radiological Health, Rockville, MD
.33.
Vogel
, A.
, Capon
, M.R.C.
, Asiyo-Vogel
, M.N.
, Bimgruber
, R.
, (1994
) Intraocular Photodisruption with picosecond and nanosecond Laser pulses: Tissue effects in cornea, lens, retina
, Investigative Ophthalmology & Visual Science
, 35
(7
):3032
–3044
.34.
Timberlake
, G.T.
, Gemperli
, A.W.
, Larive
, C.K.
, et al, (1997
) Free radical production by Nd:YAG laser photodisruption
, Ophthalmic Sing Lasers
, 28
:582
–589
.35.
Toth
, C.A.
, Narayan
, D.G.
, Cain
, C.P.
, Noojin
, G.D.
, Winters
, K.P.
, Rockwell
, B.A.
, Roach
, W.P.
, (1997
) Pathology of Macular Lesions from subnanosecond pulses of visible laser energy
, Investigative Ophthalmology & Visual Science
, 38
(11
):2204
–2213
.36.
A.
Vogel
, J.
Noack
, K.
Nahen
, D.
Theisen
, S.
Busch
, U.
Parlitz
, D. X.
Hammer
, G. D.
Noojin
, B. A.
Rockwell
and R.
Bimgruber
, (1999
). Energy balance of optical breakdown in water at nanosecond to femtosecond times scales
, Appl. Phys. B
68
, 271
–280
37.
Vogel
, A.
, Sckweiger
, P.
, Frieser
, A.
, Asiyo
, M.N.
, Bimgruber
, R.
, (1990
) Intraocular Nd: YAG laser surgery: light-tissue interaction, damage range, and reduction of collateral effects
, IEEE Journal of Quantum Electronics
, 26
(12
):.38.
World Health Organization [WHO]
, (1982
), Environmental Health Criteria No. 23
, Lasers and Optical Radiation
, joint publication of the United Nations Environmental Program, the International Radiation Protection Association and the World Health Organization, Geneva.39.
Zuclich
, J. A.
et al (1997
) A comparison of laser-induced retinal damage from infrared wavelengths to that from visible radiation
. Lasers and Light in Ophthalmology
, 8
(1
): 15
–29
.40.
Zuclich
, J.A.
, Lund
, D.J.
, Edsall
, P.R.
, Hollins
, R.C.
, Smith
, P.A.
, Stuck
, B.E.
, McLin
, L.N.
, (1999
) Experimental study of the variation of laser-induced retinal damage threshold with retinal image size
, Nonlinear Optics, Proceedings of First International Workshop on Optical Power Limiting
, Cannes, France
, 28 June - 1 July 1998
, (edited by Kajzar
, F.
) Gordon and Breach Science Publishers
, Channel Islands
, 21
(1-4
):19
–28
.
This content is only available via PDF.
© 2003 Laser Institute of America.
2003
Laser Institute of America
You do not currently have access to this content.