Why 20/20 Vision is Not Enough
Vision therapy treats eyestrain-- problems not detected by eye charts.
Remember the eye chart? It’s called the Snellen chart - and it’s the way your eyes have been tested since childhood. But it can’t spot many reading and learning problems and other eyestrain symptoms – problems that vision training with the computerized HTS Home Vision Therapy Program can solve.
The Snellen chart was developed more than 100 years ago to test distance vision. 20/20 simply means you can see what the average person can see -- with each eye -- at a distance of 20 feet. Many of us fail this test. If you are nearsighted, farsighted or astigmatic, your vision can usually be corrected to 20/20 with glasses or contact lenses.
But the chart only tests the distance vision skills needed by our ancestors for outdoor survival – spotting game and enemies from a distance.
Modern life demands different skills. We spend most of our time using our eyes within arm’s length – reading or at a computer. For such near vision, you need the eye coordination of binocular vision. Your eyes must work as a team.
Intensive near vision tasks can stress the vision system and produce many symptoms and problems. Yet, students today read almost three times the number of textbooks their parents did -- plus they often work at computers. Many have childhood learning problems. People who work in offices may spend the whole day in front of computers and suffer adult eyestrain. The most common complaints of computer users today are vision-related.
What is binocular vision?
When you read a book or work at a computer screen, you do not cover one eye as on the Snellen test. You use both eyes together as a team. This is called binocular vision. To have clear near vision, you need three skills:
- The eyes must aim together to converge -- so the image from each eye combines to become one.
- The curvature of the lens must change or accommodate to bring the image into clear focus.
- The eyes must move as a team to follow a line of print across a page and then jump to the next line - called saccadic eye movements.
Just as many of us do not have 20/20 vision for distance, many have poor binocular vision for near. Even a slight muscle imbalance in your visual system requires extra effort to keep both eyes aligned and focused. This effort may fatigue your visual system, causing headaches, a pulling sensation in the eyes, blurred vision, a loss of concentration – or other symptoms of eyestrain.
With more severe muscle imbalance or if the visual task is too demanding, you may be unable to keep your eyes constantly aligned. The system breaks down . One eye drifts out of alignment - known as intermittent strabismus. Sometimes the brain turns off the information from the drifting eye and that eye can develop total vision loss.
How can binocular problems be helped?
Eye muscle problems are not seeing problems -- so glasses alone often won’t help. However, they can usually be corrected by vision training with the computerized HTS Home Vision Therapy Program. You do eye exercises to develop the muscle coordination necessary for good binocular vision. The computerized HTS Home Vision Therapy Program is tailored to your personal binocular problem. Most binocular problems can be resolved in just a few months.
Upon successful completion of therapy, your eyes function comfortably and efficiently as a team. Your symptoms will be eliminated or significantly reduced. Near vision tasks will become more enjoyable and rewarding.