14 DAY TRIAL // People with a disability to one of the five senses, tend to compensate by sharpening the others, and a new University of Sheffield research reveals that deaf adults see better than hearing people.
To be more precise, adults who were born deaf, react more quickly to objects at the edge of their visual field than hearing people do.
This is the first time that scientists test the way that peripheral vision is developing in deaf people, from childhood to adult life.
The researchers tested completely deaf children, aged 5 to 15 years, by using a self-designed field test and comparing it to age-appropriate hearing controls, but also to deaf and hearing adult data.
The subjects had their head positioned in the center of a gray acrylic hemisphere, with 96 LEDs implanted in it, and had to watch a central glowing ring, with a camera hidden inside.
The camera monitored every eye movement the children made, when the LEDs were shortly illuminated, at three different light intensities, in a random order.
The researchers thought to make this experiment look like a game, and called it Star Catcher.
The idea behind it is for the subject to 'catch a star', by moving a joystick in the right direction, every time a flash occurred.
For example if the flash occurred above, the child had to move the joystick upwards and if it occurred to the left, they would have to move it to that position.
This way, the researchers could verify that the kids really did see the flash and not simply guessed its location.
The leader of the study, Dr Charlotte Codina, from the University's Academic Unit of Ophthalmology and Orthoptics, said that “deaf children see less peripherally than hearing children, but, typically, go on to develop better than normal peripheral vision by adulthood.
“Important vision changes are occurring as deaf children grow-up and one current theory is that they have not yet learned to focus their attention on stimuli in the periphery until their vision matures at the age of 11 or 12.”
Dr Codina, who undertook the study as part of her RNID-funded PhD, added that even if children born deaf are slower to react to objects in their peripheral vision than hearing children, deaf adolescents and adults react much faster than normal hearing individuals.
Her findings showed that before the age of 11-12, deaf children have slow reactions, but around 12 years of age, the situation improves and deaf teens between 13 and 15 years react more quickly than their hearing peers.
“As research in this area continues, it will be interesting to identify factors which can help deaf children to make this visual improvement earlier,” said Dr Codina.
The research was funded by the Royal National Institute for Deaf People (RNID) and the results were published in Development Science.