Laser damage criteria have traditionally relied on fundoscopic and/or histological evidence. These methodologies have provided limited information regarding the functional impact of observed damage and more importantly, cannot assess the transition zone between temporary and permanent visual loss. Previously we have shown that transient and permanent visual deficits can be produced by long (msec) duration laser pulses at or slightly below traditional threshold levels for retinal The present investigation extended these exposures to include Q-switched, 532 mn Nd/YAG pulses presented to awake, task-oriented nonhuman primates. At and above the ED50, single pulses of minimal spot diameter (50 % produced only minor, transient shifts in acuity although repeated exposures lead to permanent deficits over time. At lower energies (lOX below ED50), minimal spot, single-pulsed exposures produced little observable consequence until either retinal spot sizes or the number of pulses were increased. At these lower energy levels, however, no permanent functions loss was observed. Hence, the functional impact of single nsec pulses was more difficult to assess than longer msec exposures. Multiple nsec pulses and/or larger spot sizes produced visual deficits similar to those observed for msec exposures, suggesting both - temporal and spatial summation at energy levels where no permanent effects have been noted.

Permanent functional alterations in visual acuity were observed with laser exposures (HeNe, Krypton and Argon) at corneal irradiance levels below those previously reported using fundoscopic or fine histological criteria. The effects of low-level irradiation appeared selective depending upon the wavelength of the exposing source and appeared to be cumulative over time. Monochromatic as opposed to achromatic targets appeared more sensitive measures of minimal functional disruptions.

High energy, Q-switched pulses from a laser are known to produce punctate lesions on the retina. The structural alterations often extend well beyond the primary area of exposure. In this report we have examined the changes in visual sensitivity following single pulses of 532 nm light several orders of magnitude above the ED 50 level. Both temporary and long term changes in spectral acuity and contrast sensitivity indicate the functional consequences of intense laser irradiation of minute areas of the central fovea. Keywords: Visual acuity loss; Neodymium: YAG lasers; Laser hazards; Rhesus monkey; Minimal laser spot; Exposure (Physiology).

This volume contains the formal record of the lectures presented at the 9th Course of the International School of Radiation Damage and Protection held at the "E . Majorana" International Centre for Scientific Culture in Erice (Italy) from May 9 to May 20, 1989. This course was the last of a series of 4 courses, started in 1981, that were dedicated to the assessment of risk hazard from non-ionizing radiation. The proceedings of these courses were all published by Plenum Press with the following headings: 1) M. Grandolfo, S. M. Michaelson and A. Rindi, Eds. : "Biological Effects and Dosimetry of Nonionizing Radiation; Radiofrequency and Microwave Energy", Plenum Press, New York, NATO ASI Series A Life Sciences, Vo1. 49 (1983); 2) M. Grandolfo, S. M. Michaelson and A. Rindi, Eds. : "Biological Effects and Dosimetry of Static and ELF Electromagnetic Fields", Plenum Press, New York, E. Majorana International Science Series, Life Sciences, Vol. 19 (1985) ; 3) M. H. Repacholi, M. Grandolfo and A. Rindi, Eds. : "Ultrasound; medical applications, biological effects and hazard potential", Plenum Press, New York (1987). We hope that all these volumes together may represent a complete textbook and a reference for the students and scientists interested in the physics, biology, measurement and dosimetry, health effects and standard setting, in short, the risk assessment of that wide field of radiation presently classified as non-ionizing radiation. We are indebted to the Associa?ione Italiana Protezione dalle Radiazioni (AIRP), The Internat:l.

Care of Head and Neck Cancer Patients for Dental Hygienists and Dental Therapists is an advisory guide that enables dental hygienists, dental therapists, and other health care professionals to appreciate the journey undertaken by head and neck cancer patients. Focusing on the before, during, and after treatments, the book covers common head and neck cancer treatments such as surgery, radiotherapy, chemotherapy and innovative new therapies. It also discusses treatment complications such as halitosis, osteoradionecrosis, and radiation dermatitis. Some of the other sample topics discussed by the well-qualified authors include: An introduction to substance misuse and oral health and the early detection of mouth cancer The role of a dietitian in the care of head and neck cancer patients Proton beam therapy and transoral robotic surgery Physiotherapy for someone diagnosed with a head/neck cancer Lifestyle factors in oral cancer and pain management in head and neck cancer patients Care of Head and Neck Cancer Patients for Dental Hygienists and Dental Therapists is an immensely valuable resource for dental hygienists, dental therapists, and other health care professionals who work in primary and secondary care.