Probability-summation model of multiple laser-exposure effects.
A probability-summation model is introduced to provide quantitative criteria for discriminating independent from interactive effects of multiple laser exposures on biological tissue. Data that differ statistically from predictions of the probability-summation model indicate the action of sensitizing (synergistic/positive) or desensitizing (hardening/negative) biophysical interactions. Interactions are indicated when response probabilities vary with changes in the spatial or temporal separation of exposures. In the absence of interactions, probability-summation parsimoniously accounts for "cumulative" effects. Data analyzed using the probability-summation model show instances of both sensitization and desensitization of retinal tissue by laser exposures. Other results are shown to be consistent with probability-summation. The relevance of the probability-summation model to previous laser-bioeffects studies, models, and safety standards is discussed and an appeal is made for improved empirical estimates of response probabilities for single exposures.
Menendez
A R
AR
Optical Radiation Division, Armstrong Laboratory, Brooks Air Force Base, TX 78235-5215.
Cheney
F E
FE
Zuclich
J A
JA
Crump
P
P
D006801:Humans; D007834:Lasers / Q000009:adverse effects*; D015233:Models, Statistical; D011338:Probability Theory; D012160:Retina / Q000293:injuries*