Biomedical subjects

David Sliney

Publications and source records attributed to David Sliney.

5 recordsLinked to original sources

PubMed2006

Validation of ICNIRP estimates of toxicity thresholds for NIR (785 nm) light in the retinas of pigmented rabbits.

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) established eye-safe exposure limits for laser light based on estimates of the 50% exposure dose (ED50) for retinal damage in animals. The ED50 has not been determined for continuous-wave near-infrared (NIR) light, as may be used in instruments for spectroscopic analysis of the eye. The purpose of this study is to determine the ED50 of 785-nm light delivered by a Raman spectroscopy instrument on the retinas of pigmented rabbits, and to compare that ED50 to the ICNIRP estimates. Light of varying power was focused into the anterior chambers of rabbits for 4, 20, or 300 s. Estimates of spot size on the retina were determined by modifying the schematic rabbit eye with actual axial length and refractive error measurements. Masked examiners determined retinal burns from fundus photographs and fluorescein angiograms made immediately after exposure and again 48-72 h later. Thirty-five of 86 exposed eyes had retinal burns. In 12 of these the burn was not visible until 48-72 h. In 6 the burn was visible on color photographs, but not on fluorescein angiography. The ED50 retinal power density from probit analysis was 14,513 mW cm(-2), 10,369 mW cm(-2), and 5,237 mW cm(-2) for 4-s, 20-s, and 300-s exposures, respectively. Thus, the ED50 for retinal burns from 785-nm light is approximately 7 and 7.5 times the ICNIRP permitted limits for 4- and 20-s exposures, and 5.6 times the limit for 300-s exposures. This is consistent with the ICNIRP intention to set power limits several times less than ED50.

Animals↗

PubMed2005

Adjustment of guidelines for exposure of the eye to optical radiation from ocular instruments: statement from a task group of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).

A variety of optical and electro-optical instruments are used for both diagnostic and therapeutic applications to the human eye. These generally expose ocular structures to either coherent or incoherent optical radiation (ultraviolet, visible, or infrared radiation) under unique conditions. We convert both laser and incoherent exposure guidelines derived for normal exposure conditions to the application of ophthalmic sources.

Eye Injuries↗

PubMed2003

Standardized protocols for photocarcinogenesis safety testing.

Solar ultraviolet radiation (UVR) is recognized as a major cause of non-melanoma skin cancer in man. Skin cancer occurs most frequently in the most heavily exposed areas and correlates with degree of outdoor exposure. The incidence of skin cancer is also increased by contact with photosensitizing drugs and chemicals such as psoralens, coal tars and petroleum stocks. Other substances which do not act as photosensitizers, such as immunosuppressants taken by organ transplant recipients, also increase the risk of skin cancer. The U.S. Food and Drug Administration requests, on a case-by-case basis, that risk of enhanced photocarcinogenesis is assessed for many classes of drugs. Health Canada's Therapeutic Products Programme has issued a Notice of Intent to regulate pharmaceutical products which may enhance carcinogenicity of the skin induced by ultraviolet radiation. Other national regulatory agencies review such data when they exist, but their own requirements emphasize batteries of short-term in vitro and in vivo tests. While they may support drug development strategies, short-term tests have yet to be validated as predictors of the ability of drugs or chemicals to enhance photocarcinogenesis. Published protocols now describe study designs and procedures capable of determining whether test agents enhance the rate of formation of UVR-induced skin tumors.

Animals↗

PubMed2003

Ultraviolet protection factors for clothing: an intercomparison of measurement systems.

In recent years the need to standardize measurement protocols for quantifying the degree of ultraviolet radiation (UVR) protection provided by clothing has led to the introduction of a number of standards around the world. To date, these standards have specified spectral measurements of UVR transmission by clothing and fabrics. Development of a standard test method has become an important part of the testing process, and this article presents results from an intercomparison involving 10 independent testing laboratories and 11 different UVR transmission measurement instruments. In addition to comparing the measured ultraviolet protection factors (UPF), this intercomparison also incorporates detailed scan results from all 10 laboratories and highlights differences in performance of the various instruments in different wavelength regions. Careful examination of these differences can indicate where changes to the systems could be made to allow improvements both in equipment performance and in agreement of the final results. The variability in the measurements of UPF in this study suggest that the protection categories in standards may need to be broadened.

Clothing↗

PubMed2003

Laser eye injuries in military occupations.

INTRODUCTION: Lasers (light amplification by stimulated emission of radiation) play an important role in our world and their use is increasing. They are powerful tools for good, but can also cause tragedy, especially in an aviation environment. Information about injuries associated with lasers is limited. This study highlights several laser eye injuries in the U.S. military and discusses issues pertaining to them. METHODS: We gathered data from the U.S. Army Safety Center, the U.S. Army Center for Health Promotion and Preventive Medicine, and the Walter Reed Army Institute of Research. This paper describes ten representative cases of laser eye injury that occurred in the U.S. military between 1984 and 2000. RESULTS: Patients suffered retinal damage, though no corneal injury occurred. Most were caused by accidental exposure to a Q-switched, Neodynium:YAG (Nd:YAG) laser at 1064 nm wavelength. The incidents occurred both on and off duty, indoors and outdoors, and from close and long ranges. None of the victims were wearing eye protection. Inadequate training and poor equipment design were major factors in at least six of the nine unintentional cases. The tenth occurred during military operations in the Persian Gulf. All of the victims needed several months medical care and follow up. Two received medical discharges as a result of their injuries. DISCUSSION: As illustrated by these cases, human and societal costs from unintentional laser eye injuries can be reduced by improving operator training, safety procedure compliance, and equipment design. In addition, intentional laser eye injuries are a growing concern and further research is needed to design appropriate protection, treatment and countermeasures.

Adult↗