Pulses of optical radiation are counted by a pulse counter in a way representative of its effects on tissue. An analog to digital converter digitizes detected optical radiation pulses and an integrator integrates the digitally detected pluses. The integrator has a time constant characteristic sufficient to combine digitally detected pluses that are close enough together so that they are effectively one pulse with respect to tissue exposure limits. The integrator can be programmable to a particular time constant based on a thermal confinement duration of human tissue and wavelength of laser pulses. A counter circuit counts pulses, and a display displays the counted pulses. A capture circuit enables counting the number of pulses occurring within a capture duration by the counter circuit. The analog to digital converter can be configured to a sensitivity.