Researches say human vision can develop up to more than 40 yrs

Earlier, vision development was believed to mature in the first few years of life only

Human brain's vision-processing centre, that was previously thought to mature and stabilise in the first few years of life, actually continues to develop up to late 30s or early 40s, a new study has found.

Researchers at McMaster University in Canada used brain- tissue samples from 30 people ranging in age from 20 days to 80 years.

Their analysis of proteins that drive the actions of neurons in the visual cortex, or vision-processing centre, at the back of the brain recasts previous understanding of when that part of the brain reaches maturity, extending the time- line until about age 36, plus or minus 4.5 years.

The finding came as a surprise to researchers, who had expected to find that the cortex reached its mature stage by five to six years, consistent with previous results from animal samples and with prevailing scientific and medical belief.

"There's a big gap in our understanding of how our brains function," said Professor Kathryn Murphy, who led the study.

"Our idea of sensory areas developing in childhood and then being static is part of the challenge. It is not correct," said Murphy.

She said that treatment for conditions such as amblyopia or "lazy eye," have been based on the idea that only children could benefit from corrective therapies, since it was thought that treating young adults would be pointless because they had passed the age when their brains could respond.

Though the research is isolated to the visual cortex, it suggests that other areas of the brain may also be much more plastic for much longer than previously thought, Murphy said.

The research was published in The Journal of Neuroscience.