Study shows more UV exposure early morning, late afternoon

Jacksonville, FL-New research conducted in Japan found that during spring, summer, and fall, ultraviolet (UV) exposure to the eye during early morning and late afternoon was approximately double that of the mid-morning/early afternoon period that is most often thought of as peak sun exposure time.

Researchers at Kanazawa Medical University, Kanazawa, put a tiny UV sensor in the ocular segment of a specially designed mannequin. The visual line of the model was set at 15° below the horizon line (the typical line of sight when a person walks). Its face followed the path of the sun from east to west, and was always placed at the lower front side of the sun. The amount of UV-B rays entering the eye was measured and recorded from sunrise to sunset. Results were recorded and coupled with various conditions, such as solar altitude (position of the sun relative to the horizon) and the direction of the model's visual line (angle) or facial or head shape, in a relative manner.

"While it has long been thought that the risk of UV exposure to the eyes is greatest during the mid-day hours, from 10 a.m. to 2 p.m., this study suggests that from spring through fall, when the days get longer, the incidence of exposure is actually greatest earlier and later in the day," said Hiroshi Sasaki, lead researcher, and professor and chairman, Department of Ophthalmology, Division of Sensory Organ Medicine, Kanazawa Medical University.

"This study further demonstrates the need for all day UV protection of your eyes," added Cristina Schnider, OD, director-medical affairs, Vistakon, Division of Johnson & Johnson Vision Care Inc. The study was sponsored by Johnson & Johnson K.K. Vision Care Co. (Tokyo).