We can identify four key reasons for increased UV exposure:
More time outdoors
More time outdoors results in more UV exposure. In many societies, people have more leisure time and choose to spend it outdoors, increasing their UV doses.
Man-made pollution leads to thinning of the ozone. Because the ozone layer is thinning, more UVR penetrates the atmosphere.1
Longer life expectancies lead to greater UV exposure. Because we tend to live longer.
Many people don't worry about ocular protection from UV exposure. Ignoring recommendations to use effective protection puts patients at increased risk of ocular UV damage.
1. McKenzie RL, Aucamp PJ, Bals AF, Björn LO, Ilyas M. Changes in biologically active ultraviolet radiation reaching the Earth's surface. Photochem Photobiol Sci. 2007;6(3):218-31.
Children at risk
Children are particularly vulnerable to ultraviolet radiation (UVR) damage because:
- They have larger pupils1
- They have clearer lenses2,3
- They tend to spend more time outdoors unprotected and few wear sunglasses or hats4
1. Winn B, Whitaker D, Elliott DB, Phillips NJ. Factors affecting light-adapted pupil size in normal human subjects. Invest Ophthalmol Vis Sci. 1994;35(3):1132-6.
2. Weale RA. Age and the transmittance of the human crystalline lens. J Physiol. 1988;395:577-87.
3. Gaillard ER, Zheng L, Merriam JC, Dillon J. Age-related changes in the absorption characteristics of the primate lens. Invest Ophthalmol Vis Sci. 2000;41(6):1454-9.
4. Maddock J et al. Use of Sunglasses in Public Outdoor Recreation Settings in Honolulu, Hawaii. Optom Vis Sci, 2009, 86 (2): 165–166.
Researching UV exposure
Research suggests that we need to encourage appropriate protection from UV exposure throughout the year, not just during the sun-filled days of summer.
Talk to your patients about UV exposure!
Research was conducted on the Kanazawa Medical University campus in Japan in September and November 2006.1 Tiny UV sensors were incorporated into the ocular segments of a specially designed mannequin to measure UVB rays from sunrise to sunset. The visual line of the model was set at 15 degrees below the horizontal line (normal line of sight when a person walks) and its face followed the path of the sun from east to west, and was placed at the lower front side of the sun all the time.
The results were recorded, coupled with various conditions, such as solar altitude (position of the sun relative to the horizon) and the direction of the mannequin's visual line (angle) or facial or head shape, in a relative manner.
On September 21, around the time of the autumn equinox (one of two times a year when the sun crosses the equator, and the day and night are of approximately equal length), the two highest points in the UV exposure test to the eye were recorded around 9am and from 2-3pm. UV exposure to the eye for four hours from 10am to 2pm recorded nearly half of the highest UV exposure points in the morning and evening.
As the solar angle decreased (moving towards winter), peak UV exposure to the eyes moved back toward midday. On November 21, one of the highest points of exposure occurred around noon under the same conditions as the previous test.
1. Sasaki H. UV exposure to eyes greater in morning, late afternoon. Proc. 111th Ann. Meeting Japanese Ophthalmologic Soc., Osaka, Japan, April, 2007.
This study suggests that we need to encourage appropriate ocular protection from UV exposure throughout the year, not just during the sun-filled days of summer.
"While it has long been thought that the risk of UV exposure to the eyes is greatest during the midday hours from 10am to 2pm, this study suggests that from spring to autumn, when the days get longer, the incidence of exposure is actually greatest earlier and later in the day," says lead researcher Professor and Chairman Hiroshi Sasaki, Department of Ophthalmology, Division of Sensory Organ Medicine, Kanazawa Medical University.
"This study further demonstrates the need for all day protection from UV exposure of your eyes," adds David Ruston, Director of Professional Affairs, Developed Markets, Johnson & Johnson Vision Care. "Over the long term, the sun can cause irreversible harm to all structures of the eye and surrounding tissue that are left unprotected or under protected. The most complete measure of protection from UV exposure can be achieved with a combination of UV-absorbing, wrap-around sunglasses, a wide-brimmed hat and UV-blocking contact lenses."
Protection from UV exposure is just as important during the winter, cautions Ruston. While UV radiation is generally lower during the winter months, exposure can be up to 100 times higher when reflected off snow.1 This is compared to other surfaces such as grass which reflects just 1-4% of UV radiation, sand (5–25%) and water (10-30%).
1. Sliney, David H. Intraocular and Crystalline Lens Protection From Ultraviolet Damage. Eye & Contact Lens July 2011; 37: 250–258.
UV-blocking - why standard sunglasses alone are not enough
UVR reaches the eye not only from the sky above but also by reflection from surfaces such as water, sand and pavement. While most standard sunglasses can help block UV rays that enter through the lenses, non wrap-around frame styles do not prevent unfiltered rays from reaching the eyes from the sides, top/bottom of the glasses. "Because of this, standard sunglasses block as little as 50% of all UV radiation from reaching the eyes," explains David Ruston. Similarly, hats with brims offer no ocular protection from UV rays reflected up from surfaces such as pavement, sand and water.
Added protection from transmission of UV radiation for contact lens wearers
UV-blocking contact lenses help to protect against the transmission of direct and reflected UV rays that pass through the cornea into the eye, and are not blocked by wrap-around sunglasses or hats. This provides contact lens wearers with an important added measure of ocular protection.
ACUVUE® Brand Contact Lenses meet the highest standards for UV-blocking.* Find out more
*All ACUVUE® Brand Contact Lenses have Class 1 or Class 2 UV-blocking to help provide protection against transmission of harmful UV radiation to the cornea and into the eye. UV-absorbing contact lenses are NOT substitutes for protective UV-absorbing eyewear such as UV-absorbing goggles or sunglasses because they do not completely cover the eye and surrounding area.