We have all heard about how much time kids spend inside watching TV, studying, and playing video games. My seven-year old son is addicted to rainbow looms, and could loom all day if I let him. New studies have indicated that the amount of time children spend outside may decrease the risk of developing myopia.
What is myopia?
Myopia, or nearsightedness, is a vision condition in which close objects are seen clearly but far objects appear blurred. Nearsightedness is a very common vision condition, affecting nearly 30 percent of the US population, and up to 90 percent of developed East and Southeast Asian countries such as Singapore, Taiwan, China, Japan and Korea. Myopia typically presents in school age children. Because the eye continues to grow as children grow, myopia may progress until approximately age 21.
Recent studies have indicated that more time spent on near work, less time spent outdoors, higher educational level and parental history of nearsightedness are risk factors for developing nearsightedness. Spending time outdoors plays a crucial role in myopia development and can slow its progression.
A recent study presented at the Association for Research in Vision and Ophthalmology (ARVO) 2014 Annual Meeting demonstrated the importance of time spent outdoors in order to control nearsightedness. The study evaluated visual acuity (vision) and axial length (length of the eye) of 6690 multiethnic children at 6 years of age. Axial length was significantly longer in children who spent less than one hour per day outdoors than in those who spent more than 2 hours outdoors.
Jan Roelof Polling, at the University of Applied Sciences Utrecht, lead investigator of the study recommended “Children with an increased risk of near-sightedness, such as those from a near-sighted family, should be prompted to spend at least 15 hours a week outside and should avoid spending long hours doing near work, even when they are very young.”
How does spending time outdoors help with myopia progression?
The protective effect of being outdoors is not well understood. Researchers suspect that bright outdoor light helps children’s developing eyes maintain the correct distance between the lens and the retina, keeping vision in focus. The intensity and / or specific spectral distribution of outdoor lighting may be beneficial. Indoor lighting that is dim does not provide the same kind of feedback. Therefore, when children spend too many hours inside, their eyes fail to grow correctly and the distance between the lens and retina becomes too long, causing far-away objects to look blurry. Hormonal changes associated with outdoor activities may also be beneficial.
Encouraging children to spend more time outdoors can be a simple and cost-effective way to improve their vision and general health. Head outside and enjoy the summer! Just remember to keep spending time outside when school resumes.
Melissa Barnett, OD, FAAO
California Optometric Association