Friday, 27 December 2019

Eyesight & Tracking; what it is, why it matters.

This is going to be a long one - but it's worth a read because if you have a child like mine, it could change your life.

(No pressure there, then).

My son (I am purposefully not identifying which of the two it is) is bright, clever, engaging, enthusiastic and charming.  He has wide and varied interests, a great sense of humour, a fantastic singing voice, and is a sensitve soul.

My son also has learning difficulties.  You probably wouldn't realise this if you met him away from the school environment, but they have impacted significantly on his life to-date.  From the age of approximately four until now there have been periods when our family has struggled to manage the anxiety he's suffered as a result of his challenges.  I won't go into detail here - it's his story to tell, not mine  - but it's been a steep learning curve for all of us.

As a result he periodically sees an educational psychologist to help him - and us - identify the best ways to support him, educationally and at home.  In the last report we received from them, there was a footnote that read something along the lines of:

'Children with X's learning profile often have problems with scanning and tracking, so it is recommended that you take him to a developmental optometrist and get this checked.'

OK.  Scanning and what?  Developmental what?  My son's eyesight had been checked - more than once - and despite a period aged around 5 or 6 when we noticed that he blinked a lot, the opticians always reported that he had 20:20 vision.  Surely this was going to be an expensive waste of time?

Nevertheless I found a developmental optometrist, and at the end of October he had his first appointment when we learned - after a session that at certain moments seemed like so much snake oil -  that he does have a tracking problem with his eyesight.

Until then, I didn't know what tracking - as a function of eyesight  - was.  Turns out, neither do some opticians, and those that do don't necessarily know how to check it, but in brief, a tracking problem is when a person does not have perfect binocular vision.  Essentially this means that when they look at an object their eyes are not focusing on the same point on that object.  This is not a problem if the object is more than around a metre away, but the impact on close work (reading, writing, sums and so on) can be enormous.

The best way to explain that is to ask you to think about how you read lines of text.  Maybe even these lines of text.  You think you're reading them in a gradual smooth motion from left to right, yes?  I did, anyway.  But that's not what's going on, not at all.  Our eyes and brains are complex and miraculous organs - you know that, I'm sure - and when most of us read, we are using a technique (which we are not even aware of) called 'hop and stop'.  We develop this naturally once we are proficient readers and have learned how to recognise entire words rather than decoding them letter by letter.  Instead of moving smoothly from left to right, when our eyes see a line of text they break it into blocks of words.  Your brain then hops from one block to the next, stopping to read (i.e. recognise) each entire word in that block simultaneously before moving onto the next block.  For example, here are nine words as our eyes and brains might process them;

The quick brown fox jumped over the lazy dog

Subconsciously we look at each block, recognise the words, and then move on.  (The numbe of words in the block will vary with reading age, but it could be 3 words, it could be 5 or 6.  Isn't the brain amazing?).  But what does this have to do with perfect binocular vision or the lack of it?

Let's imagine you are a person with tracking problems reading a line of text.  You read well; you've moved on from decoding words one letter at a time and instead recognise words when you see them on the page.  Your brain groups them together into blocks and unconsciously you 'hop and stop' across the page.  The only problem is that since your tracking is off your two eyes are not working as a team and looking at the same blocks of text.  It's hard to explain what that means in writing, but let's give it a go.  Below is line of textual numbers:

one two three four five six seven eight nine ten eleven twelve thirteen fourteen

You're not aware of it, but it's likely that you read it in blocks, as shown in different colours below:

one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen

That's because each of your eyes, whilst working independently of each other, still focus on the same groups of words. Both eyes then send similar visual messages to your brain, which recognises and instantly understands the words.  This is perfect binocular vision.  Like I said, the brain; incredible.

Children and adults with tracking problems, however, don't see text in that way.  Their eyes over or under converge, which means the messages each eye sends independently to the brain don't match up.  My son, for example, has eyes that over-converge.  Let's imagine he's trying to read the words highlighted in red:

one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen

It should be simple, but when he tries to read the words in red, the over-convergence of his eyes means that the message his brain gets (in red) is:

one two three four five                eight nine ten eleven twelve thirteen fourteen fifteen

Unconsciously he knows something's not right.  There are two words missing, and on a subliminal level  his brain recognises that.   All humans fill in the spaces in situations like that - it's why we're able to make sense of those memes which on first sight are nonsense because of mis-spelt or missing letters - but supposing what we fill the gaps with is wrong?   My son's brain knows that's a possibility, so how to manage it, how to make sure the eyes haven't missed something important?

So X's brain does the obvious thing; it sends an instruction to the eyes to read the block of text again.  But guess what?  Those eyes haven't miraculously cured themselves in the last nanosecond.  So it might take a person with tracking problems 3 or even 4 tries to read a line of text completely - and all without ever consciously knowing that this is going on (remember, they don't know any different).  Consequently, it takes that person 3 or 4 times as much effort to read each and every line of text.  Or numbers.  Or sums. Or really any kind of close work, including music, symbols and so on.

Just think about how exhausting that would be.

And whilst this is going on, the brain of this person with tracking problems is distracted from various other executive functions it should be managing.  Listening.  Focusing on what's going on around them.  Moving information from short to long term memory.  Filtering out white noise.  Working out the sense of what they are reading.  I could go on, but I'm sure you get it.

In my sons' case this diagnosis explained a great deal whilst still leaving me wondering what to do next. Would it mean surgery, or lengthy sessions of special exercises?  How was I going to persuade him to buy into it all? But no.  This situation - this condition that has impacted on my son's entire learning process until now - can be (mostly) fixed, and not with invasive medical procedures or exhausting daily sessions of eye exercises, but with a special pair of glasses (available on the NHS), and regular checks to ensure the prescription is correct.  And there are no special exercises; for the glasses to help correct the problem all he has to do is wear them for all close work (reading, writing, sums etc) for the next eighteen months to three years.  Whilst they will always be helpful, he will - after that time - not need them as a matter of course.

I've been sitting staring at the screen trying to find the right words to sum up what has happened since my son got his glasses.  From the first moment, it was as if I was picking up another child from school.  A boy who told me about his day.  Who had the energy to converse.  Who will sit and do his homework without real complaint, without panicking he won't be able to do it, without running away in a tantrum when things didn't go to plan, without hiding (literally) from the fear of failure.  A boy who goes to school so much more happily in the morning.

It's been a game changer.   He still has learning difficulties, but now he has more energy to deal with them, and as a consequence so do we.


This is not a sponsored post.  But here's a link in case you're interested in finding out more about scanning and tracking and possible treatments for it.