Wavelength Dependence of Ocular Damage Thresholds in the Near-IR to Far- IR Transition Region: Proposed Revisions to MPEs

摘要

This report summarizes the results of a series of IR laser-induced ocular damage studies conducted over the past decade. The studies examined retinal, lens, and corneal effects of laser exposures in the near-IR to far-IR transition region (wavelengths from 1.3- 1.4 m with exposure durations ranging from Q-switched to cw). The corneal and retinal damage thresholds are tabulated for all pulsewidth regimes and the wavelength dependence of the IR thresholds is discussed and contrasted to laser safety standard maximum permissible exposure (MPE) limits. The analysis suggests that the current laser standard MPEs could be beneficially revised to: (1) relax the IR MPEs over wavelength ranges where unusually high safety margins may unintentionally hinder applications of recently developed military and telecommunications laser systems; (2) replace step-function discontinuities in the IR MPEs by continuously varying analytical functions of wavelength and pulsewidth which more closely follow the trends of the experimental retinal and corneal ED50 threshold data; and (3) result in an overall simplification of the safety standard MPEs over the wavelength range from 1.2 m to 2.6 m. A specific proposal for amending the IR MPEs over this wavelength range is presented.