Inheritance of Refractive Error in Millennials.
Level 4 - case-series / case-control
Cross-sectional classical twin study evaluating variance components
PubMed 32424231 · doi:10.1038/s41598-020-65130-w
What was done
Investigated the variance and heritability of refractive error in a sample of 100 twin pairs attending university in southeast Spain, comparing the pattern to historical data from an older generation of the same ethnic background.
What was found
The cohort had a 77% prevalence of myopia. Statistical modeling indicated that variance in refractive error was primarily accounted for by shared environmental factors and only to a lesser degree by additive genetic factors. Compared to older cohorts of the same ethnic origin, this millennial sample showed higher myopia prevalence and reduced heritability. Exact numerical variance estimates and confidence intervals were not reported in the abstract.
Why it matters
Illustrates that refractive error heritability is population- and environment-dependent, suggesting recent lifestyle and educational shifts among young adults may outweigh genetic predisposition in driving myopia risk.
Limits
The abstract lacks specific numerical values for heritability coefficients, variance breakdown, and twin zygosity counts. The sample size is modest (100 twin pairs) and restricted to university students from one geographic region, which carries high educational selection bias and limits broader generalizability.
Cited by
- contradicts Ophthalmological refractive traits and poor eyesight are overwhelmingly genetic.