Picosecond optical breakdown: Tissue effects and reduction of collateral damage

The effects of picosecond laser‐induced optical breakdown on tissue were investigated using high‐intensity 40 ps Nd:YAG laser pulses at 1.06 μm. Tissue damage was evaluated using the corneal endothelium in vitro as a model system. Systematic studies were performed to determine the scaling of the tissue damage and damage range with pulse energy. For suprathreshold lesions, the radius of the damage zone varies as the cube root of the pulse energy, in agreement with simple physical scaling laws. A minimum damage range of less than 100 μm was observed for pulse energies of 8 μJ. Damage morphology was investigated by scanning electron microscopy. Three different damage patterns were observed: cell damage, cell removal, and rupture of Descemet's membrane. Different irradiation geometries were used to study damage mediated by either the shock wave or the cavitation bubble. Comparative studies using 10 ns pulses demonstrated that picosecond pulses yielded a significant reduction in collateral tissue damage.

[1]  J Mellerio,et al.  Study of the temporal and spatial dynamics of plasmas induced in liquids by nanosecond Nd:YAG laser pulses. 1: Analysis of the plasma starting times. , 1988, Applied optics.

[2]  C. Puliafito,et al.  Plasma formation and shielding by three ophthalmic neodymium-YAG lasers. , 1983, American journal of ophthalmology.

[3]  D. Gaasterland,et al.  Endothelial damage thresholds for retrocorneal Q-switched neodymium:YAG laser pulses in monkeys. , 1985, Ophthalmology.

[4]  D Aron-Rosa,et al.  Use of the neodymium-YAG laser to open the posterior capsule after lens implant surgery: a preliminary report. , 1980, Journal - American Intra-Ocular Implant Society.

[5]  D H Sliney,et al.  Laser photodisruptors. Damage mechanisms, instrument design and safety. , 1983, Ophthalmology.

[6]  S. Trokel,et al.  Endothelial repair following Nd:YAG laser injury. , 1984, Investigative ophthalmology & visual science.

[7]  D. Aron-Rosa.  Use of a pulsed neodymium-Yag laser for anterior capsulotomy before extracapsular cataract extraction. , 1981, Journal - American Intra-Ocular Implant Society.

[8]  Werner Lauterborn,et al.  Acoustic transient generation by laser‐produced cavitation bubbles near solid boundaries , 1988 .

[9]  A Vogel,et al.  Cavitation bubble dynamics and acoustic transient generation in ocular surgery with pulsed neodymium: YAG lasers. , 1986, Ophthalmology.

[10]  F. Docchio,et al.  Lifetimes of Plasmas Induced in Liquids and Ocular Media by Single Nd:YAG Laser Pulses of Different Duration , 1988 .

[11]  F. Fankhauser,et al.  The ultrastructural features of laser trabeculopuncture and cyclodialysis. Problems related to successful treatment of chronic simple glaucoma. , 1979, Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde.

[12]  M M Krasnov,et al.  Q-switched laser goniopuncture. , 1974, Archives of ophthalmology.

[13]  R. J. Simmons,et al.  Shock-wave effect on anterior segment structures following experimental neodymium:YAG laser iridectomy. , 1985, Ophthalmology.

[14]  M M Krasnov,et al.  Laseropuncture of anterior chamber angle in glaucoma. , 1973, American journal of ophthalmology.

[15]  E. Sherrard,et al.  Damage to the corneal endothelium during Nd/YAG photodisruption. , 1985, The British journal of ophthalmology.

[16]  Carmen A. Puliafito,et al.  The Nd-YAG Laser in Ophthalmology: Principles and Clinical Applications of Photodisruption , 1985 .

[17]  James G. Fujimoto,et al.  Time-resolved measurements of picosecond optical breakdown , 1989 .

[18]  J. Fujimoto,et al.  Time-resolved studies of Nd:YAG laser-induced breakdown. Plasma formation, acoustic wave generation, and cavitation. , 1985, Investigative ophthalmology & visual science.