Do we understand the true risk factors from myopia? Big data studies help!
Refractive error, in particular myopia, remains a leading cause of visual impairment worldwide. But do we really understand the risk factors?What is driving the growth of myopia? Genetic predisposition, lifestyle changes resulting in a combination of decreased time for outdoor activities and increased near work, and reduced light levels and exposure to daytime light have all been attributed. Using both the National Health and Nutrition Examination Survey (NHANES) and the The Intelligent Research In Sight (IRIS) registry developed by the American Academy of Ophthalmology, the burden of myopia has been elucidated by identifying those at greatest risk of vision loss. In an additional analysis of this registry revealed risk factors from a longitudinal study of over 600,000 US patients age 35 or younger.
The risks factors identified were:
- Living in the eastern region of the United States
- Hispanic ethnicity
- Refractive error present at an early age
- Seeing providers in high-income communities
As you can tell, the data while interesting has lots of confounders. For example, seeing a provider in a higher income community does not mean that high income causes myopia. Rather it is likely that those at risk are being screened more readily than lower income communities. And the link between Hispanic ethnicity and myopia was first reported in this study so more effort is needed to further validate these findings. While we are learning more about myopia many unanswered questions still plague our field. With the advent of these larger data studies, more presentations are likely to be elucidated.