Why should a child who sees 20/20 need glasses?
LOW PLUS LENSES AND PRISMS
by Merrill D. Bowan, O.D.
The application of low plus reading lenses and prisms, either
separately or in combination, has had remarkable impact upon
students and adults with reading and comprehension problems. This has been known and researched for decades and has been clinically explored more thoroughly over the past ten years in our office. The results, demonstrated by changes in reading speed, word decoding, fluency, comprehension and -ultimately - grades, has been dramatic in a very high percentage of cases.
Not every student/reader will benefit from these stress-reducing lenses. But almost all of those who do, demonstrate improvement almost instantaneously. Most parents reading this pamphlet have just seen and heard this happen. This brochure is meant to explain more thoroughly what is happening and why lenses are important for your child's learning ease.
Why does this technique work?
This application works because many of these children suffer from visual function and visual processing problems. The lenses reduce the stress at two levels, one functioning, and the other in the actual processing.
One must understand a little about vision and reading, to be
able to truly appreciate what happens when the low plus reading
lenses and/or prisms are used.
Learning is a biological drive, it appears, as shown by research.
The Brain craves to learn. The Brain wants to experience new events, and while all the senses pour data into the Brain, the fastest method to receive the data is by reading. Reading is a highly complex task in which we have put the sounds making up words into a letter code. We then reconvert them back into the thoughts contained in the words. At least 80% of all our learning occurs through the visual sense, much of that is through reading.
Reading, however, is a very stressful task for the Brain. It
actually provokes an avoidance response much like the "fight or
flight" response: the heart rate increases; the pupils dilate; respiration can increase; adrenaline is produced; the perspiration rate increases - just as if an emergency were occurring. Two studies demonstrated this (Harmon, Pierce) and also that reading lenses decreased these responses.
Why should that happen? It appears that much of the stress is triggered by the complicated demands on the nervous system. What is happening in the Brain when this occurs? Well, the Voluntary Nervous System controls the eye muscles; and the Involuntary Nervous System controls the focusing of the lens. Both systems must work together. (The Involuntary and Voluntary Nervous Systems never work together in this way anywhere else in the body.) It is an extraordinary stress because of that. It creates distress.
There is another balancing act that must happen between the
two subdivisions of the Involuntary system, but that is less demanding than the main conflict going on between the Voluntary and Involuntary divisions of the Brain. For a while, the Brain can stand the shock, but after 20-30 minutes, its comfort zone is challenged and will either signal the person to stop reading with symptoms of eyestrain or it will demand energy that has been going to decoding of the words. When this happens, the reading almost turns into "Greek" and the reader gets to the bottom of the page without absorbing anything. This happens to all of us at times. The third thing that can happen is that the structures of the eye can change to become nearsighted, a functional change which will reduce the stress because the eye is then focused for reading distance.
So, what do the lenses do?
Applying plus lenses in front of the eyes signals the Brain
that the reading target is now farther away, which reduces the
distress. Prisms do the same thing, but appear to do so from a
top-down fashion, whereas plus lenses operate in a bottom-up
fashion. They both also enlarge the target size on the retina slightly and this may help change the ease with which the brain
distinguishes letters, since we now know that reading disabled
children have trouble distinguishing letters that are too close
The total effect of the lenses and prisms is to reduce the stress by enlarging the target size and optically pushing the target just far enough away to reduce the demand upon the Brain's balancing act. This keeps the visually-problemed student from fatiguing as quickly, and allows the processing of language to occur with much more effectiveness. It removes a significant
barrier to learning in children who have these visual processing
and function difficulties.
Let me share one recent case with you:
A young child received a pair of plus/prism lenses, but the father was not present for the very dramatic demonstration that
had confirmed the benefit of this lens prescription. He hesitantly agreed to the lenses.
A few days later, the father walked by the child's room as she was working on her computer. He heard the slow "ticky-tick" of the keys. Looking in, he noticed that she was working without her new lenses. The father asked her to stop and get the glasses, because of our instruction for her to use them at the computer. As he started to leave the room, he heard his daughter, now with glasses in place, typing again - but now, he heard a faster typing - as he put it, a "tickety-tickety-tickety" of the computer keys.
The daughter was now working three times faster, and in this
way, the father got to "hear" the glasses in action. Any doubts
he had were now gone, her mother later told me. This is just one example of the performance changes that can occur when these lenses are used as part of the solution to your child's learning problems.