Risk of early myopia associated with parental myopia

Association of Parental Myopia With Higher Risk of Myopia Among Multiethnic Children Before School Age looks in the March 2020 issue of JAMA Ophthalmology looks at data not previously before noted. There are tons of studies regarding how school age children develop myopia and nearsightedness. This one hones in on how myopia develops in children before school starts and can potentially help answer the age-old question of “When should I bring my child in for their first eye exam?”

They not only looked at refractive error but axial length and corneal curvature radius. This does bring up a slight issue I have with this paper. They equate nearsightedness and myopia as being the same thing. They repeatedly bring up the point that some children has increased axial length without having myopia. Technically, the children are myopic, but they simply aren’t nearsighted. Much like a post-op LASIK patient is not longer nearsighted but is still myopic.

On to the results! There is very compelling evidence here. The study includes almost 10,000 children spread out over the US, Singapore, and Australia.

Compared with children without parental myopia, the odds ratios for early-onset myopia were 1.42 (95% CI, 1.20-1.68) for children with 1 parent with myopia, 2.70 (95% CI, 2.19-3.33) for children with 2 parents with myopia, and 3.39 (95% CI, 1.99-5.78) for children with 2 parents with childhood-onset myopia

They did not specifically control for how much near work was done and how much time they spent outside. The didn’t feel like it played much of a factor, and I tend to agree. Acuity in little ones is not good compared to older children, so most tasks are done at near anyway.

…we believe that parental myopia may contribute to a child’s myopia in at least 2 different ways: first by setting up a more myopic baseline from very young ages, as suggested by the present analysis, and later by increasing susceptibility to myopic shift during school age, as seen in studies of school-age myopia progression…

The strong data here suggest that children of myopia parents need closer monitoring especially under age four. Most parents don’t bring their children in until they start school. I wouldn’t start atropine therapy on these kids, but it would give me more data to decide how progressively myopic they child may become.