Unexplained reading difficulties: could it be convergence insufficiency?

BY FRAN GOLDIN

Are you concerned about your own child, or a child in your class, who has symptoms which include headaches, poor tracking, double vision and/or inability to keep their place when reading?

As a specialist orthoptist who treats and studies irregularities of the eyes especially those of the eye muscles and specialises in ‘convergence insufficiency’, I may well be able to assist.

What is ‘convergency insufficiency’?

Convergence insufficiency (CI) is ‘a common binocular vision disorder that is often associated with a variety of symptoms’. These include: eye strain, headaches, blurred vision, double vision, sleepiness, difficulty concentrating, movement of print while reading and loss of comprehension after short periods of reading or performing close activities’ (Archives of Ophthalmology 2008).

A definition of primary CI in the UK is a near point of convergence greater than 10 cm from the nose.  To example that if you brought a pencil slowly, slowly, to the nose fixing on the tip one should be able to maintain fixation all the way to the nose.  If one eye wanders outwards this is loss of fixation and is called convergence insufficiency.

The second type of convergence is secondary.  This is due to a latent squint called an exophoria or it can be due to presbyopia which is when adults need reading glasses around the age of forty or it can be due to diseases such as thyroid.  This occurs is mainly in adults.

This causes people, not just children, to lose their place when reading, poor stamina of reading, missing words, missing lines and even sometimes double vision.  This also can cause frontal headaches as lactic acid builds in the medial rectae muscles which are needed for convergence and one gets referred pain over the eyebrows causing a headache.

This is why, often, students and children, complain of headaches during schoolwork.

Essentially, the human visual system is designed so that the paired eyes and the six muscles in each eye can work to such a high degree of teaming that the two eyes perform as one.  This is due to the nerve impulses in each eye.  The skill is intimately related to eye movement control and focussing ability.  Fixation is the precursor of good visual concentration and is required for good reading skills.  These skills must be maintained and effortlessly for prolonged periods to do well at school.

Whilst working for the National Health Service I found myself to be more and more interested in convergence issues that affected children’s reading and tracking abilities.  I was also very passionate about it as both of my children were dyslexic and there is a high incidence of convergence weakness in people with dyslexia, although one does not have to be dyslexic to have convergence insufficiency.

Treating convergence insufficiency

Very often frontal headaches are misunderstood. People are asked to go for MRI scans and CAT scans and yet no one has first checked their convergence.  I have had many patients who have been for various neurological tests and in the end, I have treated their convergence and the headaches go away.

Children with reading difficulties are often prescribed low hypermetropic (long-sighted) glasses by their optometrist to help with their reading.  All this does is magnify the print and does not cure the problem.

Ophthalmologists and orthoptists do not believe that children need reading glasses as this is an aid not a cure and children’s eye muscles are like elastic and therefore should not need reading glasses unless there are exceptional circumstances.  The same applies to giving children prisms (these bend the rays of light).  Prisms again do the work of the eye muscles and can make the eyes weaker long term.  It is advised that the first point of treatment is exercises to cure conditions such as convergence insufficiency and accommodative anomalies.

The treatment of convergence insufficiency is not intrusive, and it just requires exercises. I am a great believer in not overloading children, and I find that just three to five minutes of exercise daily works extremely well.

The sort of exercises I give are putting the pencil into the hole of a biro, bringing a pencil slowly to the nose, and exercises using physiological diplopia which is a normal phenomenon using everyday sight.  Exercises are fun and adapted to the age of the child and I start off doing it every day and when I discharge them after four visits, I ask the patient to do the exercises just once weekly for two minutes to prevent a recurrence of symptoms.

I also test patients for Irlens Syndrome using a test called the intuitive coloured filter test.  Very often children with convergence insufficiency tend to like a coloured overlay and they use this for perhaps three months and then find that they do not need it anymore but this is a test I do on the second visit of every patient.

I love the fact that a child can come to me not reading or is reluctant to read and when they have finished the course of exercises, they are reading with much more pleasure and not losing their place.  Of course, this does not happen in all cases but most of the cases improve significantly and they find schoolwork and homework much easier.

Take away tips:

  1. Diarise regular eye tests for your child – it can be easy to forget!
  2. If there are concerns about the child’s reading, do ask if they experience any blurring, movement of text, or missing out words/lines. Remember this may be normal for them and they may not realise that reading doesn’t need to be experienced like this.
  3. If there are any concerns, in the first place, ask children to read with a book held upright so that you can observe if their eyes are tracking together.  As a teacher you often sit side by side and you may not consider what the eyes are doing.

For more information, contact: www.frantheorthoptist.co.uk

Image credits: Artwork by Ria Mishaal, using components by herself and chomplearn, LightField Studios/Shutterstock.com