apparent source, <retinal hazard>

real or virtual object that forms the smallest possible retinal image (considering the accommodation range of the human eye) for a given evaluation location of the retinal hazard

Note 1 to entry: The accommodation range of the eye is assumed to be variable from 100 mm to infinity. The location of the apparent source for a given viewing position in the beam is that location to which the eye accommodates to produce the most hazardous retinal irradiance condition.

Note 2 to entry: This definition is used to determine, for a given evaluation position, the location of the apparent origin of laser radiation in the wavelength range of 380 nm to 1 400 nm. In the limit of vanishing divergence, i.e. in the case of a well-collimated beam, the location of the apparent source goes to infinity.