Keeping both eyes on the ball
Poor vision is a problem that affects many of us, and it often gets worse with age. But what if there was a way of improving the vision of even healthy eyes?
The visual system is very adaptable, especially during development. The brain changes the way it processes visual information depending on the type of information it receives. Most of us have stereoscopic vision meaning that the brain uses information from both eyes to help it perceive depth in the environment.
However, there is a critical period during a child’s development where this ability must be learnt by the brain. If the information coming from both eyes is not synchronised during this period, a person may forever lose the ability to have stereoscopic vision. This sometimes happens in children with strabismus, otherwise known as ‘lazy eye’.
This leads to an interesting question: if the visual system is adaptable, can we train it to be better?
There are some therapeutic visual training exercises. For example, children with strabismus are often fitted with a patch over their dominant eye. This encourages the muscles controlling the lazy eye to become stronger and equalises the visual input of the two eyes.
A recent study found evidence that training may not only improve deficits, but may also improve normal vision. In this study, baseball players at an American university performed visual training for 25 minutes a day over the course of two months. The training simply involved searching for patterns on a screen, which gradually became dimmer and more difficult to perceive.
The results were striking: there was an average of 31% improvement in vision. Furthermore, seven players reached 20/7.5 acuity, which means they were able to read text at three times the distance of a normal observer.
More importantly, the players who underwent training displayed improved performance on the field. The authors even suggest that the difference may have led to an “additional four to five team wins”. They claim that this training improves “mental fitness” and compare it to going to the gym to improve your muscle strength.
These findings are exciting for two reasons. Firstly, it shows us that normal vision can be improved with training, demonstrating that our potential is greater than our day-to-day performance. Secondly, it shows that the visual system is still adaptable even in adulthood.
This may have implications for the way we treat visual decline associated with aging. This also may suggest that the ‘critical period’ theory of visual development is wrong, and that conditions such as loss of stereoscopic vision can be treated.