There is currently some degree of controversy as to the magnitude of cataract and other ocular diseases related to human lifetime exposure to UV radiation (UVR). Concerns about the depletion of stratospheric ozone and the related increase in terrestrial UVR exposure have emphasized the importance of resolving this controversy. A careful study of ocular exposure to environmental sunlight demonstrates that it is not simple to determine accurately the level of solar UVR exposure of the human eye. Past attempts to measure or calculate UVR exposure of the eye have generally relied on the measurement of ambient UVR in sunlight with global monitors. Unfortunately, such attempts have seldom assessed properly the large role of ground reflection, the horizon sky contribution, the degree of lid opening and the extreme lateral component of UVR incident on the eye. A series of recent ocular dosimetry studies are described which have considered all of these factors. In addition, the value of different types of eye protection is shown to vary widely depending on the frame design. The dosimetry studies can be confirmed by a biological dosimeter--the human cornea. Because the action spectrum and threshold for human photokeratitis are well defined, the living cornea can serve as a biological dosimeter for ocular exposure.