New and emerging myopia management: The value of outdoor time

Outdoor time is a fairly easy lifestyle recommendation that most parents embrace as a strategy to help prevent the onset of their child’s myopia. Providing families with specific guidelines will further encourage compliance and ultimately success. (Image credit: Adobe Stock/alexei_tm)

One of the primary questions parents ask me is, “Is there anything I can do to PREVENT my child from becoming nearsighted?” In years past, that very question would prompt a bewildered look and an attempt to fumble through an answer mostly consisting of some variation of the 20-20-20 rule.*

Although the 20-20-20 rule is still a solid recommendation, recent studies have provided practitioners with more specific recommendations to help potentially prevent the onset and slow the progression of myopia. This blog series will explore new and emerging anti-myopia treatments and discuss how to add them to your conversations of myopia management and prevention with concerned parents.

Most practitioners and parents are aware that spending time outdoors is a much healthier alternative to indoor time, especially when indoor time is coupled with screen time. However, until recently, there have been many unanswered questions on the details of what exactly constitutes outdoor time.

How does outdoor time impact myopia? The exact reason why outdoor time has an impact on myopia is unknown. Although the answer is likely multifactorial, there is one leading hypothesis. During outdoor time, dopamine is released from the retina which, in turn, retards axial elongation.¹

What is the recommended amount of outdoor time? The current recommendation is at least 2 hours per day but the more time outdoors the better. In fact, children who spent less than 13 hours per week outdoors had significantly higher odds of incident myopia.² Although time outdoors has been proven to prevent or slow the onset of myopia, it has not been definitively proven to slow progression. Nonetheless, children who are already myopic benefit from time outdoors—outdoor time can potentially offset the risk factors of parental myopia and increased near work and result in less overall myopia. ^3,4

Does it matter what the child is doing while outdoors? Many parents assume outdoor activity solely refers to sports. Although sports have both physical and mental health benefits on children, myopia is not necessarily impacted by whether or not the child is engaged in a sports activity. The key is to avoid doing near work while outdoors. Parents need to be aware that reading a book or using a device or computer outdoors will not counteract the negative impact of prolonged near work. Additional recommendations for appropriate outdoor time can include riding a bike, going on a walk, gardening, or having a picnic.

Does it matter whether it is a sunny or cloudy day? The bottom line is that being outdoors during daylight hours—regardless of cloud coverage—is better than being indoors. The exact level of light intensity necessary to have an impact on incident myopia is yet to be determined, but traditionally, light intensity over 1000 lux is considered outdoor time. While outdoor light intensity levels can vary widely, essentially any outdoor scenario is sufficient to reach this threshold.

Is UV protection still important? Although there are health and vision benefits of being outdoors, we must still be mindful of the need for UV protection, which include sunglasses, a hat, and sunscreen.

Outdoor time is a fairly easy lifestyle recommendation that most parents embrace as a strategy to help prevent the onset of their child’s myopia. Providing families with specific guidelines will further encourage compliance and ultimately success.

*Editor's note: The 20-20-20 rule was designed to reduce eye strain for those using computers for extended periods of time. It was never designed to prevent myopia.

References:

1. French, A.N., et al., Time outdoors and the prevention of myopia. Exp Eye Res, 2013. 114: p. 58-68

2. Xiong, S., et al., Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review. Acta Ophthalmol, 2017. 95(6): p. 551-566.

3. Rose, K.A., et al., Outdoor activity reduces the prevalence of myopia in children. Ophthalmology, 2008. 115(8): p. 1279-85.

4. Jones, L.A., et al., Parental history of myopia, sports and outdoor activities, and future myopia. Invest Ophthalmol Vis Sci, 2007. 48(8): p. 3524-32.