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A series of experiments were conducted in vivo using Yucatan miniature pigs (Sus scrofa domestica) to determine thermal damage thresholds to the skin from 1319-nm continuous-wave Nd:YAG laser irradiation. Experiments employed exposure durations of 0.25, 1.0, 2.5, and 10 s and beam diameters of ∼0.6 and 1 cm. Thermal imagery data provided a time-dependent surface temperature response from the laser. A damage endpoint of fifty percent probability of a minimally visible effect was used to determine threshold for damage at 1 and 24 h postexposure. Predicted thermal response and damage thresholds are compared with a numerical model of opticalthermal interaction. Resultant trends with respect to exposure duration and beam diameter are compared with current standardized exposure limits for laser safety. Mathematical modeling agreed well with experimental data, predicting that though laser safety standards are sufficient for exposuress, they may become less safe for very long exposures. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.JBO.18.12.125002]

A series of experiments are conducted in vivo using Yucatan mini-pigs (Sus scrofa domestica) to determine thermal damage thresholds to the skin from 1940-nm continuous-wave thulium fiber laser irradiation. Experiments employ exposure durations from 10 ms to 10 s and beam diameters of approximately 4.8 to 18 mm. Thermal imagery data provide a time-dependent surface temperature response from the laser. A damage endpoint of minimally visible effect is employed to determine threshold for damage at 1 and 24 h postexposure. Predicted thermal response and damage thresholds are compared with a numerical model of optical-thermal interaction. Results are compared with current exposure limits for laser safety. It is concluded that exposure limits should be based on data representative of large-beam exposures, where effects of radial diffusion are minimized for longer-duration damage thresholds

Five-axis goniometric stages have been used in laser eye safety research for over forty years. The stages are able to translate in three dimensions and rotate about either eye of a prone-placed subject. This report describes the design, implementation, and operation of a five-axis goniometric stage. The latest design incorporates many ideas from previous versions while adding reliability and functionality improvements, such as a position indicator option. Most notably, the current design merges the rotary and linear portions into a single contained motion system. A manual control box facilitates the operation of the two rotational axes and three linear travel axes. The design criteria for the goniometric portion of the stage nominally called for +/- 15 degrees pitch adjustment and +/1 40 degrees of rotational adjustment. The XY section was designed for 6.5 inches (16.5 cm) of travel in each axis. The height stage section was required to have 8 inches of range with a center of motion approximately 46 inches above the floor., Prepared in cooperation with Air Force Research Laboratory (AFRL), Brooks City-Base, TX. The original document contains color images.

A computer-based model has been developed to explore the effects of lasers on the eye. The model was developed using a technique known as BioFusion (registered trademark) which embodies a software engineering and knowledge acquisition methodology. The technique provides a formal means for developing a model by gathering, organizing, analyzing, documenting, synthesizing, and implementing the vast amount of knowledge needed about a biological process into a working computer simulation. The resulting PC-based model can then be used to explore questions in an in silico environment, and to work synergistically with in vitro and in vivo experiments., Prepared in collaboration with St. Mary's University, San Antonio, TX. The original document contains color images.

A series of experiments in a new animal model for retinal damage, cynomolgus monkeys (Macaca fascicularis), have been conducted to determine the damage threshold for 12.5-nanosecond laser exposures at 1064 nm. These results provide a direct comparison to threshold values obtained in rhesus monkey (Macaca mulatta), which is the model historically used in establishing retinal maximum permissible exposure (MPE) limits. In this study, the irradiance level of a collimated Gaussian laser beam of 2.5 mm diameter at the cornea was randomly varied to produce a rectangular grid of exposures on the retina. Exposures sites were fundoscopically evaluated at post-irradiance intervals of 1 hour and 24 hours. Probit analysis was performed on dose-response data to obtain probability of response curves. The 50% probability of damage (ED5O) values for 1 and 24 hours post-exposure are 28.5(22.7-38.4) microjoule and 17.0(12.9-21.8) microjoule, respectively. These values compare favorably to data obtained with the rhesus model, 28.7(22.3-39.3) microjoule and 19.1(13.6-24.4) joule, suggesting that the cynomolgus monkey may be a suitable replacement for rhesus monkey in photoacoustic minimum visible lesion threshold studies., Prepared in collaboration with Northrop Grumman, San Antonio, TX. Presented at the Optical Interactions with Tissue and Cells (18th) held in San Jose, CA on 22-24 Jan 2007. Published in Progress in Biomedical Optics and Imaging, v8 n12, ISSN 1605-744; Proceedings of the SPIE, v6435 paper 64350Q, Feb 2007, ISBN 9780819465481. This article is from ADA484275 Conference on Optical Interactions with Tissue and Cells (18th) Held in San Jose, California on January 22-24, 2007