Scotopic Sensitivity syndrome

Scotopic Sensitivity syndrome (SSS) has a cluster of symptoms and although little is known about the physiological basis of SSS, it is thought that it is due to the spectral modification of light. That is, individuals with SSS perceive the world around them in a distorted way as a result of sensitivity to certain wavelengths of light. This can lead to reading difficulties because those individuals do not see the printed page the same way as proficient readers do. For example, the page may flash, the words become blurred, move, change shape or reverse or the background may pulsate.

Characteristics of Scotopic Sensitivity syndrome

Reading Characteristics:

  • Reads in dim lighting
  • Skips words or lines
  • Reading is slow and hesitant
  • Slow reading rate
  • Inability to read continuously
  • Misreads words
  • Trouble tracking
  • Avoids reading

Complaints While Reading:

  • Strain or fatigue
  • Headaches or nausea
  • Falling asleep
  • Eye pain
  • Print indistinct
  • Background uncomfortably bright

Who is affected?

Anyone may be effected by SSS but it is generally seen as a complex and variable condition associated with dyslexia and other learning disabilities.

It is a perceptual difficulty rather that a vision problem which involves difficulties with the functioning of the eye. Therefore it can occur with someone who wears glasses or someone who has perfect vision.


There is still much research into what causes SSS and thus into the solutions/treatments. However, it appears that through experience, providing coloured filters changes the spectral content of the light and appears to stabilise the printed page. These filters can either be in the form of overlays plastic sheets to place on the page of text, or tinted glasses. There is an almost limitless number of colour combinations that can be prescribed. Only an intensive diagnostic process can determine the correct colour, providing maximum benefit.


Changing the Environment
For individuals with Irlen syndrome, the classroom is a very stressful environment. Many other environments, such as the workplace, restaurants, shopping malls and supermarkets, are equally stressful for those with Irlen syndrome. There are several ways that you can remove these stressors from your environment.

Scotopic Sensitivity syndrome and the Irlen Lens System
There is growing evidence, based on both research and personal reports, that many autistic individuals see their world in a maladaptive, dysfunctional manner. Researchers at U.C.L.A. and the University of Utah have found evidence of abnormal retinal activity in autistic individuals.


Sue's Scotopic Sensitivity syndrome Website:
Sue Runyon (BS, MA from Bradley University) is a elementary school teacher with a Master's Degree in Curriculum and Instruction. She has been teaching since 1983 and have been a certified SSS screener since 1991.

The Irlen Institute Website:
The Irlen Method has helped children and adults worldwide become successful rather than continue to experience enormous difficulties. This method has received international acclaim and Helen Irlen's work has been included in professional journals, textbooks, National Geographic, TV shows such as 60 Minutes and Good Morning America, ABC World News With Peter Jennings, NBC News and has been the subject of many news broadcasts by the BBC and news shows in Ireland, Hong Kong, Netherlands, New Zealand, and Australia including their 60 Minutes.

Weyburn Scotopic Sensitivity Awareness Group Website:
The support group consists of parents of children and/or adults who have Scotopic Sensitivity syndrome. We are a non-profit group who have formed to hopefully make a difference for our children and the Adults diagnosed with Scotopic Sensitivity syndrome. We want to create an awareness in the Public of this complex condition.