For painting/drawing models, what is the maximum exposure time and maximum light intensity of a spot shining in your eyes at a fixed position?
That is: before the damage to your eyes becomes unrepairable?
Is the light intensity actually the problem, or is it purely the heat which causes the problem?
Clarfiication edit: A painting/drawing model is a person exerting a modeling discipline. Contrary to a photography model, a painting model performs for one or more painters/drawers who will use the model's body as an inspiration for their artistic works.