Health & Wellbeing

Controlling tiny eye movements may lead to better vision

Controlling tiny eye movements...
By tracking and compensating for test subjects' "fixational eye movements," scientists have shown that such movements may help maintain 20/20 vision
By tracking and compensating for test subjects' "fixational eye movements," scientists have shown that such movements may help maintain 20/20 vision
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By tracking and compensating for test subjects' "fixational eye movements," scientists have shown that such movements may help maintain 20/20 vision
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By tracking and compensating for test subjects' "fixational eye movements," scientists have shown that such movements may help maintain 20/20 vision

One would think that having normal 20/20 vision is due mainly to the anatomical characteristics of the eye. According to a new study, however, tiny eye movements play a large role – and the findings could lead to new treatments for poor sight.

For some time now, scientists have been aware of continuous, involuntary, minuscule shifts in a person's gaze, known as fixational eye movements. Because these movements are so small, we're not even aware that they're taking place.

Previously, it was thought that they played no significant role in how people see the world. More recently, though, it was found that by shifting an image across the retina, these movements expose more of the retina's light-sensing cells to that image. It has been theorized that as a result, the brain is better able to "see" what the eyes are looking at.

Led by Prof. Michele Rucci and grad student Janis Intoy, researchers at the University of Rochester decided to put this theory to the test. They started by having a group of volunteers with 20/20 vision view a standard Snellen eye chart, which was displayed on a video screen. Snellen charts are the type with 11 lines of letters, with the letters in each row being smaller than those in the row above.

When the test subjects initially viewed the chart from a distance of 20 feet (6 m), they could accurately make out the letters down to at least the eighth row. This is standard for people with 20/20 vision.

In a second round of tests, however, the chart moved around slightly on the screen, automatically compensating for the participants' fixational eye movements in real time. This meant that the image of the chart was exposed to fewer of their retinas' receptor cells. The test subjects were thus (on average) only to able to read down to the sixth line, indicating sub-par 20/30 vision.

More research still needs to be conducted, although it is now conceivable that by undergoing therapy to help improve their motor control, near- or farsighted people could experience an improvement in their vision.

"We found that achieving 20/20 vision is not only the outcome of good optics and a healthy retina but also fine motor control, to a level that eludes awareness," says Rucci. "Impairment in visual acuity may originate from eye movements, a factor that is presently not monitored at all."

A paper on the study was published this week in the journal Nature Communications.

Source: University of Rochester via EurekAlert

3 comments
Douglas Rogers
A large correction, like 4D, is caused by a short eyeball. This will need a 4D lens. For an IOL, the length is determined acoustically.
sidmehta
Brilliant insight. Any follow up on whether micro shifting exercises helped improve vision?
HansPro
Very interesting research. I am a fit 64 years old and waay back in 1990 I noticed I could not read vehicle number plates clearly from afar as before. Went to the optometrist who checked me out and he prescribed glasses for driving and also threw in a ‘deal’ of two pairs of very expensive ‘Terminator RayBan’ sunglasses… yes, the same Arnie wore in the movies! That night I went for a drive and I could see the plates crystal clear… but! On looking to my passenger seat and door, the whole section was distorted bulging outwards as if the passenger section was blown up like an inflated balloon! – the door and seat was ‘bent’ outwards and backwards by about 45 degrees! Aghast and nauseated, I ripped the glasses off my face and the interior of the car returned to normal again. I duly returned the glasses the next day. Optometrist’s reaction? “Oh yes, that is quite normal, but majority of people go thru’ life like zombies and are not tuned in to their surroundings like you, so they never see this distorted phenomena”. Got my money back. Then weirdly a few days later, a middle-aged American women visited our country on a lecture tour… she's famous for fixing her eyesight herself by doing ‘eye exercises’. Decided to try my own exercises for awhile and my eyesight returned to pin-sharp for far objects. Close-up objects always remained sharp. Stopped the exercises years ago and my eyes stayed sharp up to the present. Oh, BTW, I have been eating eggs morning, afternoon and evenings since school going days and is the best complete meal ever. Maybe that helped a bit?