The critical period for some aspects of human sight can be extended past childhood

This 2013 human study provided further details of critical periods in human development. The study subjects were:

“11 children enrolled in a humanitarian and scientific effort in India that provides corrective surgery to children with treatable cataracts and subsequently studies their visual abilities.”

The researchers found:

“The human visual system can retain plasticity beyond critical periods, even after early and extended blindness.

We define “early-onset” blindness as occurring before 1 y of age. We define “extended” blindness as lasting at least until early childhood, when many visual abilities in normally developing children reach adult levels. Contrast sensitivity in particular develops until approximately age 7 in normally sighted humans.

Of the 11 children, five had no discernible improvement, whereas one child’s vision grew worse, probably because of post-surgical complications. Five of the patients showed remarkable enhancement, however, and of these, an 11-year-old and a 15-year-old showed 30-fold improvement in contrast sensitivity.

“The visual brain can be plastic for longer than we originally thought,” concludes Kalia. “Many of the kids dramatically improve their quality of life.”

http://www.pnas.org/content/111/5/2035.full “Development of pattern vision following early and extended blindness”

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s