Scientists have discovered a cell in the eye’s retina that may cause myopia when it dysfunctions.
The dysfunction may be linked to the amount of time a child spends indoors and away from natural light.
It is estimated that up to 40 per cent of British adults suffer myopia or nearsightedness, meaning they struggle to see distant objects clearly.
The newly discovered retinal cell, which is highly sensitive to light, controls how the eye grows and develops.
If the cell instructs the eye to grow too long, images fail to be focused on the retina, causing nearsighted vision and a lifetime of glasses or contact lenses.
Experts say the retina contains a signal to focus the image in the eye and this signal is important for properly regulating eye growth during childhood.
Study leader Professor Greg Schwartz, of Northwestern University, in Chicago, said: “For years no one knew what cell carried the signal.
“We potentially found the key missing link, which is the cell that actually does that task and the neural circuit that enables this important visual function.”
He said indoor light had a high red/green contrast, which activates clusters of photoreceptors in the human eye, creating the equivalent of an artificial contrast image on the retina.
It’s likely the human version of the retinal cell would be over stimulated by such patterns, causing too much growth of the eye, leading to myopia.
Professor Schwartz said: “The eye needs to stop growing at precisely the right time during childhood.”
The findings appear in the science journal Current Biology.
In the study researchers recorded electrical signals from cells in a mouse retina under different light patterns.
Professor Schwartz said: “This discovery could lead to a new therapeutic target to control myopia.”
In further research he hopes to find the gene specific to this retina cell. Then scientists can turn its activity up or down in a genetic mouse model to try to induce or cure myopia.
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