Welcome to Vision Therapy and Behavioural OptometryClick to listen highlighted text!Welcome to Vision Therapy and Behavioural Optometry
Shaylers Vision Centre
Irlen syndrome - Visual Stress - are coloured lenses the best option?
Often individuals diagnosed with Irlen Syndrome (also called Scotopic sensitivity or Mears / Irlen syndrome) are frequently prescribed coloured overlays or tints, but is this their best option?
Irlen Syndrome is thought to cause visual problems for many people because it alters the way they see things. The problems are caused by the way in which the brain interprets the visual information that is being sent through the eyes. Having Irlen Syndrome prevents many people from reading effectively and efficiently. Individuals are often unaware of the extra energy and effort they are putting into reading and perception.
HOWEVER the symptoms of Irlen Syndrome are the same as those with binocular instability . Before relying on coloured lenses / overlays read this research paper
Irlen syndrome is typically treated by the provision of coloured overlays or tints.
The Cerium Overlay Testing Set consists of 2 sets of A5 overlays in each of the 12 colours equally positioned around colour space. The colour is selected by process of elimination.
Colored overlays have been shown to reduce visual stress and increase reading speed on the Rate of Reading Test by more than 25% in just 5% of schoolchildren aged 7-8 (ref http://www.essex.ac.uk/psychology/overlays/) - hardly a significant percentage!
According to Prof. Stein of Oxford University, most children with this condition, which he felt is due to a magnocellular deficit, can be helped with blue or yellow tints
Irlen syndrome and the Intuitive Colorimeter
The Intuitive Colorimeter is used under the direction of an Optometrist to logically and sequentially explore colour space to find the optimal Precision Tint for the relief of perceptual distortions in Visual Stress.
The instrument independently changes the 3 parameters of colour, hue, saturation and brightness while the eyes are colour adapted. This will give a final colour which is extremely precise to each individuals needs. The colour will be different for each person and the precision coming from a choice of over 100,000 colour combinations now available. In its most effective form, this prescription will be delivered as Cerium Precision Tinted Lenses.
The tint is selected rapidly and efficiently in an examination lasting about 20-30 minutes carried out by a specialised practitioner.
Note that the optimal colour which will benefit each individual can change over time, especially with children. It is therefore very important that the patient visits the specialised Optometrist regularly for re-evaluations.
Irlen syndrome and vision therapy
Wilkins and Evans have stated in papers published on this subject that children that find coloured lenses beneficial have an underlying binocular vision problem. In his book Visual Stress, Wilkins stated on numerous occasions that the symptoms of visual stress disappeared when one eye was closed (indicating the problem of" Visual stress" had its origin in binocular vision!)
Studies carried out in the US have shown that children, diagnosed with Irlen syndrome no longer find coloured lenses beneficial following vision therapy!
Optometrists that incorporate syntonics within their vision therapy programs are aware that limited exposure (less than 10 minutes) to coloured light can have a significant change in visual function as it affects the functioning of the visual system, however if the child looks at the light too long, they start to go into stress mode with a change in heart beat, breathing rate, fidgetability, etc.
Thoughts as the advisability of wearing tinted lenses
Consider then the effect of wearing a “tinted lens” for long periods...
Hypothetically, if you have a headache, you may take an aspirin; then is it a good idea to take lots of aspirin to treat the problem more quickly or perhaps... permanently due to death!
Similarly what are we doing to the autonomic nervous system of children when encouraging them to wear precision tints for long periods, perhaps all day at school or even all day? No one knows as there have been no studies on the effect of long term use of these lenses
The effects of Low plus lenses and yoked prism lenses that can often treat these problems more safely and effectively than coloured lenses will be considered in a later article and they can be prescribed without the potential dangers of coloured lenses
Is there a use then for tinted lenses?
Yes! There are still people who despite having good visual processing still experience "Visual Stress" and find reading more comfortable reading with a tinted lens/overlay