Repetitive pulse laser data and permissible exposure limits

Two methods are described for the calculation of permissible ocular exposure to repetitive pulse laser radiation. The rationale for these methods (the correction factor method and the alternate method) is based upon available experimental data from several laboratories. The ED (sub 50)s (Effective dose for 0.50 probability of an ophthalmoscopically visible retinal lesion) for repetitive pulse exposures expressed in terms of the total intraocular energy are proportional to the pulse train duration to the 3/4 power. The continuous wave ED(sub 50)s exhibit the same dependence on the exposure duration; however, the repetitive pulse ED(sub 50)s were always some factor below the continuous wave ED(sub 50)s. This correction factor is dependent on the pulse repetition frequency and the duration of each individual pulse in the train. It was applied as a multiplicative correction to the continuous wave maximum permissible exposure to obtain the permissible exposure for repetitive pulse condition.