Biomaterial Database

Diode laser-pumped, frequency-doubled neodymium: YAG laser peripheral iridotomy. 1997

M M Abreu, and R A Sierra, and P A Netland

Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, USA.

OBJECTIVE The solid-state, continuous-wave, frequency-doubled neodymium: yttrrium-aluminum-garnet (Nd:YAG) laser pumped by a diode laser has several advantages, including air cooling, higher electrical to optical efficiency ratios, portability, and the use of standard 110-V AC electrical service. The authors wanted to evaluate the use of the frequency-doubled Nd:YAG laser for peripheral iridotomy and to compare the tissue interactions of this laser with those of the argon laser. METHODS The authors developed a diode laser-pumped, solid-state, and portable frequency-doubled Nd:YAG laser with a wavelength of 532 nm. The effects of peripheral iridotomy with the frequency-doubled Nd:YAG laser and the argon laser were evaluated in pig eyes in vitro and in rabbit eyes in vivo. Specimens were prepared for light microscopy and scanning electron microscopy. RESULTS The frequency-doubled Nd:YAG laser successfully created patent iridotomies in all animal eyes treated. The following parameters were used to create penetrating burns: duration of 0.1 second, spot size of 100 microns, and power of 500 mW. In rabbit eyes, the mean number of pulses (P = .16) and the total energy required (P = .21) for iridotomy were not significantly different for the argon laser compared with the frequency-doubled Nd:YAG laser. Gross and histologic evaluation showed similar thermal effects in iris tissues for both the frequency-doubled Nd:YAG laser and the argon laser. The mean zone of thermal damage was 178 +/- 19 microns for the frequency-doubled Nd:YAG laser and 163 +/- 24 microns for the argon laser (P = .14). Scanning electron microscopy showed less disruption of the surface of the lesion for the frequency-doubled Nd:YAG laser compared with the argon laser. CONCLUSIONS Successful peripheral iridotomy can be performed with the frequency-doubled Nd:YAG laser. Coagulative effects with the frequency-doubled Nd:YAG were similar to those with the argon laser, and the thermal damage zones were comparable in size.

UI	MeSH Term	Description	Entries
D007498	Iris	The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.
D008855	Microscopy, Electron, Scanning	Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.	Scanning Electron Microscopy,Electron Scanning Microscopy,Electron Microscopies, Scanning,Electron Microscopy, Scanning,Electron Scanning Microscopies,Microscopies, Electron Scanning,Microscopies, Scanning Electron,Microscopy, Electron Scanning,Microscopy, Scanning Electron,Scanning Electron Microscopies,Scanning Microscopies, Electron,Scanning Microscopy, Electron
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D005901	Glaucoma	An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)	Glaucomas
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D053685	Laser Therapy	The use of photothermal effects of LASERS to coagulate, incise, vaporize, resect, dissect, or resurface tissue.	Laser Knife,Laser Scalpel,Surgery, Laser,Vaporization, Laser,Laser Ablation,Laser Knives,Laser Photoablation of Tissue,Laser Surgery,Laser Tissue Ablation,Nonablative Laser Treatment,Pulsed Laser Tissue Ablation,Ablation, Laser,Ablation, Laser Tissue,Knife, Laser,Knifes, Laser,Knive, Laser,Knives, Laser,Laser Knifes,Laser Knive,Laser Scalpels,Laser Surgeries,Laser Therapies,Laser Treatment, Nonablative,Laser Treatments, Nonablative,Laser Vaporization,Nonablative Laser Treatments,Scalpel, Laser,Scalpels, Laser,Surgeries, Laser,Therapies, Laser,Therapy, Laser,Tissue Ablation, Laser