Nearsightedness may be an inherited trait, study shows

San Francisco-The refractive errors of myopia and hyperopia are thought to be, by Gu Zhu, MD and colleagues, primarily inherited. The group's research, published in the June 2008 issue of Ophthalmology, the journal of the American Academy of Ophthalmology, also has found-on the long arm of chromosome 5-the probable location of genes that help determine axial length.

Eight hundred ninety-three individuals were used from the Tasmania Twin Eye Study and Brisbane Adolescent Twin Study, Australia, to obtain axial length measurements. Proportional impacts of genetic and environmental factors on axial length were analyzed in these samples of identical and fraternal twins.

It was found that genetic factors explained approximately 80% of axial length values, after adjusting for age and sex. Research team member David Mackey, MD, said that new measurement techniques will likely make collection of axial length data routine in future research on myopia and other refractive error.

Using a genome scan on a subset of 318 individuals, the researchers found string evidence for the role of chromosome 5 in the inheritance of axial length. A genomic analysis of a larger study group has been launched by researchers to confirm and refine this finding.