Retinal injury from laser radiation

During the past 35 years, a wide body of biomedical research has been conducted to understand the biophysical factors which influence laser induced retinal injury. Although, the optical effects which influence the retinal imaging and the initial physical events which lead to the absorption and dissipation of the laser energy are well understood, the stages of biological damage which take place after the deposition of energy and for hours or even days later are not so well understood. Occupational health and safety standards which provide maximum permissible exposure (MPE) limits are based both upon the theoretical understanding and a large body of experimental data and human accident experience. Current laser safety research has recently focussed almost exclusively on deriving retinal injury thresholds for sub-nanosecond exposures. Setting limits in this temporal region has been difficult, since there have been conflicting data sets and there are limited data to extrapolate to other spectral regions.