Our practice is closed until Tuesday 21st March for essential maitenance


Dorothy Crystal MCOptom specialises in the optometric investigation of reading. writing and learning difficulties.

What is Dyslexia?

People with specific learning difficulties have problems with certain areas of academic performance, yet do well in other subjects and can have above average intelligence. The most common type of specific learning disability is reading difficulty, often called dyslexia. About 10% of the UK population have some form of dyslexia. About 4% are severely dyslexic, including some 375,000 school children. Dyslexia affects all kinds of people regardless of intelligence, race or social class. Leonardo da Vinci and Einstein are both thought to have been dyslexic.

Dyslexic children are usually poor at spelling and may be intelligent in conversation but have trouble with written language.
This can cause them to under-achieve at school.

Vision and Dyslexia

When assessing, an Educational Psychologist or Specialist Dyslexia Teacher is likely to ask if the child has any eye problems.

The most common visual problems in dyslexia are a reduced ability to focus close-up and poor unstable co-ordination of the two eyes (binocular instability). Binocular instability would not normally be detected in a school eye test and may even be missed using traditional examination methods in a hospital setting

A child with dyslexia, dyspraxia, dyscalculus or suffering from Aspergers Syndrome or from autism, may benefit from being assessed for binocular instability because restoring binocularity can help reading. Even people with a mild specific learning difficulty, perhaps not bad enough to be called dyslexia should be checked for binocular instability.

In the UK about 100 UK registered optometrists specialise in eye conditions relating to dyslexia. Their services are not yet available under the National Health Service, even for children.

For some children and adults too, coloured overlays and lenses make a remarkable difference for close work. They have said that the print stays still and does not dance about. (They did not know that it stays still for other people!) Some say that it is not as dazzling as white paper or that the spaces between words are clearer, so they can concentrate on the words. When their eyes are comfortable, they may be able to read or write faster and for longer periods. With less effort, they understand more of what they read and retain the information longer.

Coloured overlays have been shown to increase reading fluency in about 20% of school children.

In 5% of children the increase in reading speed with overlays is greater than 25%.

The colour of the overlay required to achieve the maximum relief needs to be worked out for each person and this may change over time.

The City Coloured Overlay Screener

Based on the screening protocol devised by Professor Arnold Wilkins for the Intuitive Overlays, The City Coloured Overlay Screener is a computer program we use to see if someone is likely to benefit from using a coloured overlay while reading and predicts the optimum colour.

Many people spend just as long looking at computer screens as printed papers. If they benefit from using a coloured overlay for normal reading they are also likely to benefit from changing the background colour of their computer screen. The Coloured Overlay Screener also calculates the optimum computer screen colour (RGB number) and gives instructions for changing it.

The overlays that Prof Wilkins designed are called the 'Intuitive Overlays' and are similar to overlays are sold by Cerium Visual Technologies, the company which markets the Intuitive Colorimeter under licence from the UK Medical Research Council.

Profound improvements

Vision therapy is the name for a treatment plan to improve visual efficiency and visual processing allowing a child to be more responsive to educational instruction. Of course there is no direct cure for learning disabilities or dyslexia. However we have seen children in our clinic where vision therapy has produced significant educational gains. These children are not only achieving more but are more confident generally. Parents have said it's like living with a different child.

Dorothy Crystal runs a special clinic for the optometric assessment of people with learning difficulties from Crystal Optometry in Edinburgh. She is happy to report her investigations, outcomes and recommendations to people such as occupational therapists, educational psychologists and audiologists. Her work has been featured in: 

The Times newspaper 11th April, 2005
Optometry Today 18th November, 2005
The Mail on Sunday You Magazine 29th October 2006
The Sunday Times 3rd June 2007
BBC Radio Scotland -The Investigation was broadcast at 0850 BST on Monday, 4 June 2007

In January 2011, Dorothy took over the clinical work of Dr Nadia Northway who created Rainbow Readers, a specialist service to improve reading. This service continues from Crystal Optometry in Edinburgh.

Please note we do not hold a list of other optometrists in the UK specialising in this field.