The results of a recent study of myopia in Chinese children may offer insights into the condition’s impact on all affected kids, as it implicates choices more so than genetics. Study subjects had higher levels of myopia, in part, due to homework duration and electronic device use, new research published in the Journal of Ophthalmology suggests. Additionally, the investigation found that age, parental myopia, TV use, sleep duration and outdoor activities were risk factors for the condition.

The researchers randomly selected schools in each of the 12 urban districts and rural counties in Jiangsu Province and included 2,623 students aged six to nine. The students underwent comprehensive exams, and their parents provided basic information through questionnaires.

The myopia prevalences were approximately 19% for boys and 17% for girls. The spherical equivalents for the worse eye were 0.3±1.2D for boys and 0.4±1.2D for girls. Considering genetics in the male patients, roughly 33% of fathers had myopia compared with 37% of mothers. About 37% of female patients’ fathers and 40% of their mothers had myopia.

The study used environmental and genetic indexes to determine the influence of both factors on myopia development. The genetic index calculation was low, at 0.125, suggesting that genes only play a 12.5% role in myopia development, while the environment was a much greater contributor at 87.5%.

The researchers are in the process of planning a long-term follow-up study to improve the accuracy of the environmental and genetic indexes.

Zhang X, Wang Y, Pan C, et al. Effect of genetic-environmental interaction on Chinese childhood myopia. J Ophthalmol. November 6, 2020. [Epub ahead of print].