Many environmental factors, including climate and geography, may pose risks to long-term ocular health if appropriate precautions are not taken. This page focuses on the cumulative effects of environmental factors—specifically UVR and high-energy visible light—on Healthy Sight.
For information about Environmental factors and Healthy Sight Now, click here: Healthy Sight Now: Environment
Where individuals live may influence how well they see. Geography—including climate, latitude, and longitude—figures into a number of determinants of Healthy Sight, including solar radiation and ozone depletion. Even in the same geographic locale, environmental exposure to UVR can vary significantly depending upon the particular season and even the specific time of day.
The indoor environment can also impact Healthy Sight, so that where individuals work, how they work, and what kind of work they do may all affect how well they see—as well as how satisfied and comfortable they are with how they see. Eye fatigue, eyestrain, “visual” headaches, “computer vision syndrome,” and “sick building syndrome” may all relate to the work environment and working conditions.
Chronic UVR Exposure Always Warrants Protection
UVR intensity is higher in certain geographic areas, specifically at higher altitudes and in latitudes relatively closer to the equator. Direct sunlight actually does not pose the greatest risk for UVR—snow has the highest UVR reflectance factor, followed by water and sand.
For those who live in generally sunny climates, the issue of chronic UVR exposure becomes critically important. The association between chronic UVR exposure and increased risk of such vision-threatening conditions as cataract and age-related macular degeneration has been established by multiple large, long-term clinical studies. For long-term Healthy Sight, which is the goal of Healthy Sight Counseling, adequate UVR protection (ideally 100% UVA and UVB protection) is important under environmental conditions of chronic high-level UVR exposure.
And of course, the presence of snow, water, or ice increases the long-term threat to ocular health posed by UVR exposure, as well as adversely affecting the immediate visual experience due to problems with diminished contrast and exaggerated glare.
Certain times of the day tend to place an individual at heightened risk for
solar UVR exposure. While the ocular risk from UVR is always present (since
UVR exposure is always a possibility), the highest risk in temperate climates
generally occurs in the late morning/early afternoon, between approximately
10 AM and 2 PM. Ocular protection is especially important during these periods.
Even small doses of UVR can
pose significant health risks, both on an immediate and a long-term basis,
and the tissues of the eye may be particularly susceptible to these risks.
And certain groups, including those with diabetes, and children, may be at
increased risk.