The increasing industrial and commercial uses of lasers have resulted in renewed interest in the potential eye hazards of such devices. The relevant anatomy and physiology of the eye is discussed in relation to such sources and to the mechanisms of laser induced damage. Using the retina as an example, laser induced damage is described together with the subjective symptoms that such damage may produce. A brief review is given of empirical studies for determining laser damage thresholds, and the way in which such figures are used to determine the safe viewing levels incorporated in current Codes of Practice.