After Optilexia, eye-tracking weakness is easily the second most important cause of reading difficulty. Around 30% of dyslexics have some degree of eye-tracking weakness and unless it is alleviated it will hold back their reading, whatever else you do. So this is a make-or-break issue when it is present.
Skipping of words and lines of text
Poor accuracy with word endings
Tendency to be overwhelmed by a page of text
Better performance with single words and larger text sizes
Better performance when fresh, worse when tired
Possible difficulty following a moving object with the eyes
Tendency to follow a moving object by twisting the head
Rubbing and watering of the eyes when reading
Sometimes combined with a general difficulty with fine motor coordination
Poor awareness of punctuation
A tendency to accelerate into a new sentence, rather than pause at a full stop
Most of us take for granted our ability to focus our two eyes on a single point, making detailed sense of what we see interpreted in three dimensions and the ability to move our eyes in synch from one spot to another. But there are exquisitely complex and delicate processes involved.
We look at someone else and presume that they are having the same visual experience that we do. An old school yard question is "do you see green like I do?" The answer is no! I know that because I am red:green colourblind and see far less red in everything than the average person. I find it hard to distinguish whether someone is dead or alive, even though I can clearly see a red traffic light as red.
In the same way, quite a lot of people have far less stability to their visual perception than one presumes, just looking at them. I watched a child trying to read across a line of digits recently and he was literally squirming in his seat with the effort. He was quite unable to achieve the task. He would jump three or four digits and got stuck at the midline of the row every time.
That is despite the fact that you would never know he had any problem just looking at him. He had also just passed a standard eye test with a 20:20 rating. Indeed his mother had been totally unaware of any problem and an opthamologist had also completely missed his difficulty during her examination. I have also know gifted sports players who have this same difficulty!
So, just because you are not perceiving any eye-tracking difficulty in someone does not mean that it's not there.
The position of each of your eyes is controlled by six extra-occular muscles. They are stimulated by neurones from your motor cortex. The motor cortex receives information from:
The frontal lobe
The position sensors from all twelve muscles
The visual cortex
The inner ear
The flocculus (a part of the cerebellum at the back of your head)
All these inputs combine to determine what stimulus is sent to each muscle in each eye. And that allows you to move each eye by fractions of a degree to bring your focus in both eyes onto any point you choose, even if your head is actually moving at the time.
It seems a miracle it all works for any of us!
Anyhow, it is easy for it not to work so well. If that is the case, the individual will tend to avoid tasks that require a lot of eye-tracking. So that makes it worse. And then reading along a sentence of small words, divided by little gaps, will be very hard, even if your decoding is good.
The good news is that. like many neural issues, eye-tracking weakness is highly treatable. Some people think your brain function is fixed. That is absolute rubbish. Just look at the level of recovery possible for stroke victims, despite completely losing parts of their brain! To achieve that they actually have to retrain some other part of their cortex to take over the lost function.
We always recommend going to see a Behavioural or Developmental Optometrist, if there is any suspicion of eye-tracking difficulty. They should be able to test for it more accurately and suggest the best solution. A standard optometrist will not be trained for this.
The optometrist may suggest an intervention such as prism glasses to help improve the teaming and tracking of the eyes, if they feel that will help.
But the very simplest solution is to do eye-tracking exercises.
We recommend holding an arm out in front of you and following your finger as it sweeps back and forth across 12-18 inches, while keeping your head still. It is an easy exercise which can be done anywhere. That is important because the key thing is to do short sessions very regularly.The goal should be ten sessions of 20 seconds per day. You will then often see a good result in around 10 days.
Like any exercise, it can be hard to remember. But, if it is the difference between reading or not reading, it has to be worth it.
Also it is important to maintain 3-4 sessions per day for the next few months. The easiest thing to do is a session each time you brush your teeth or go to the bathroom.
Most optometrists will recommend other exercises too, but occasionally we hear of optometrists who say that exercises cannot fix eye-tracking weakness. That is the reverse of our experience. Of course, for the exercises to work they do have to be done regularly, so they may have had poor experiences because the exercises were done too infrequently.
We also hear of optometrists who fail to observe eye-tracking weakness when it is clearly present from the empirical evidence. The easiest test is to get the person to read across a line of large digits and then compare that performance with how they read a line of small digits. If there is a difference then it has to be an eye-tracking issue, if they basic eye function has already been tested.
Like almost everything, eye-tracking weakness displays a "normal distribution", meaning that you get a full range of severity. Ironically it is often easier to detect and fix when it is really severe than not so severe. With mild cases we sometimes have difficulty persuading people to take it seriously, even though it is still an important issue.