Binocular Vision

Binocular vision is at the core of everything an optometrist does.

Although sight accounts for just 20% of the five major senses (the others being hearing, touch, taste, and smell) about 80% of the way most of us experience the world is through vision.

In order to navigate this world we need to be able to identify objects, track them and perceive their depth (3D vision). In order to navigate school we need to be able to learn to read so that we can assimilate information easily and accurately.

Most people assume that all vision problems can be corrected with spectacles or contact lenses. But a surprisingly high number of children (with and without spectacles) have functional eye disorders. A functional eye disorder is where a little piece (or more than one piece) of the visual pathway doesn’t work or works inefficiently. To a child this may appear as blurred vision, difficulty tracking along a line of text, problems remembering what they’ve read, being a slow reader, difficulty catching or hitting a ball, headaches, or double vision. To an adult such as a teacher, the child might appear to be a slow worker; they might mix up words when they read; they might try to avoid close-up work like reading or writing altogether; they might become anxious or angry, stare out of the window, get up and wander round the class or distract other children.

These children are frustrating to many optometrists. In our consulting room they may appear to have great vision, reading the bottom line of the chart with ease, or conversely they may struggle to read more than half way yet when we examine them we can find nothing that requires them to wear spectacles. These children are also frustrating to their teachers, who are only too aware that they are underperforming without a seemingly good reason. And they are frustrating to their parents who are worried that their child has been labelled a ‘problem’. At the centre of this is a frustrated child, rapidly losing confidence and feeling a failure compared to their peers.

This is where a specialist binocular vision examination can be very useful. Binocular vision disorders are extremely common, but often intermittant, causing symptoms some of the time in some situations but not all of the time in all situations (at least in the early stages).  Because of this these issues can be missed if they aren’t looked for specifically.

Binocular vision disorders may be helped with spectacles, contact lenses or vision therapy (kind of physio exercises for the eyes), or any combination of these. Please note that in spite of claims made in certain corners of the internet none of these solutions are a cure for dyslexia or ADHD and they are definitely not a magic bullet (though the results can seem like magic sometimes). The aim of any vision appliance or therapy is purely to enable child using their visual system in such a way that clear, comfortable, accurate vision is possible. Many children with dyslexia or ADHD may also display or develop an underlying binocular vision problem, the symptoms of which exacerbate the problems they are having with the dyslexia or ADHD! When the binocular vision problem is fixed the dyslexia or ADHD appear to improve, but in reality we’ve simply removed one problem, so they now have more energy and resources to devote the other problem.

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