Visual Stress and Classroom Management


Use of an overlay 

Encourage the use of the chosen overlay for a short period because the benefit may not be evident within the first few minutes: symptoms of visual stress can take a while to develop. However, it is good practice for staff to leave the individual free to choose whether to use the overlay long term. (The amount of encouragement and reminders will depend upon age, additional needs, ability, temperament and peer pressure).


The continued voluntary use of the overlay is an indication for precision tinted lenses. 


When an overlay is beneficial:


       The overlay should be used for all reading tasks.

(It can be cut to the size of a bookmark to allow discreet use but is generally more useful in A5 or A4 size.) 


       Reading Mask: Can make it easier to stay on the line. When making a reading mask cut a horizontal slot about 160 x 5mm) in two pieces of thin card.  Insert an overlay between them.  Many suppliers e.g. LDA ( sell a plastic version. 

       Encourage the individual to keep the overlay in a reinforced cardboard envelope to avoid scratching it.

Check the overlay periodically to see whether it has become scratched or creased, and change if necessary.

       If symptoms return and the overlay is reported as no longer working, reassess the individual to see if another colour is now helpful.

       Reading rulers can be bought in a sufficiently large variety of colours. Colour preference can change with time so review annually or more frequently if symptoms return.

       Avoid sharing books (overlays/reading masks/reading rulers are a hindrance to those who don’t need them). Students need to use their optimum position for reading, for example to avoid glare.

       Custom eyes is a service from Guide Dogs for the Blind. For the price of the original book they will reprint print books in larger print, with different fonts and word spacing, and coloured paper to make reading accessible for everyone.



       Exercise books (and coloured paper) with lines and squares if required are available and may be obtained online from many suppliers. Use the student’s choice of colour, ideally the closest to the colour of the chosen overlay. (Coloured paper may be useful even when the student has precision tinted lenses.)

       Coloured paper can be used for photocopied and written work.  (Ruled lines can be photocopied onto coloured paper from a sheet of file paper. Use fine lines that are widely separated.) Handouts/desk copies can be printed on white paper and read using an overlay.

       Students should be allowed to choose the colour of pens that they write with. They should be encouraged to experiment in order to find the optimum colour. This applies to all written work.  (Teachers could use this pen colour for marking.)

       Students should be allowed to choose the colour of pens for whiteboard use, and can be made responsible for handing the pen to the teacher.

       Students should be permitted to write on alternate lines of the page thus reducing vertical crowding.


Coloured graph paper


Choose a weakly saturated colour with thin widely separated lines



Computer screens

       Students can experiment with different background colours and different text colours to achieve best individual options. Where possible, choose a screen without pulse-width modulation  

       Students can experiment with brightness and contrast settings to reduce eye strain. 

Digital coloured screen filters are available in the accessibility settings of most computers including Microsoft, Chromebooks and iPads/iPhones. There are also apps and downloads available.

For example, you can download Colourveil for Windows: or Helperbird:    

       Kindles have a reflective screen with no flicker and a good range of fonts.


Board work

Extra time may be required for reading and copying from the board. Desk copies of board and overhead projector work are very useful. If the student has an iPad using programs such as Teams, it is possible to share resources with the teacher rather than looking at the white board. 


Preparation of Text

Space lines and characters widely. Be careful about choosing borders (i.e. border art) with repetitive designs, and avoid if in doubt. Use size 14 point or greater. Use Google Open Sans, Verdana or Tahoma. Print onto recycled paper as this has a rough surface that will blur sharp edges of text.


Visual material in general  

       Avoid reducing the size of visual material when photocopying.

       Avoid cluttered visual material in handouts. 

       Avoid large blocks of text.

Text should be widely spaced both across and down the page.


Examinations and deadlines

       In general, worksheets and examination papers should printed in a typeface at least than N14.  Double spacing is useful. See above for appropriate font type.  Paper of the appropriate colour should be used. If the exam script (reading only) is on coloured paper which is not the same as the chosen overlay photocopy onto white paper and use the overlay. Allow the student to write their responses on paper of a colour chosen by them from a selection of different colours. Refer to Guidance notes from JCQ and STA. N.B. Any reasonable adjustments must reflect the student’s normal way of working.

       Many individuals with visual stress also have reading difficulties and may require specialist help for this reason. Although individuals with additional learning needs may be granted extra time, those who also experience visual stress may require additional rest-breaks.  They are likely to suffer headaches when exposed to print for a prolonged period. 

       Students with visual stress may benefit from using text-to-speech features that read aloud text (can be through head/ear phones). Text-tospeech tools are inbuilt in most computers. The CALL Scotland website has detailed information on this:



School lighting (fluorescent and LED) often flickers. The flicker is too rapid to be seen but is known to cause headaches. Check for flicker using the slo-mo video on a smart phone. If the lighting is flickering, try to change it. Teachers should be able to finely control artificial lighting and natural light in relation to the student’s needs. (Simple use of on/off switch, use of blinds should be sufficient). 

       If possible, venetian blinds should be avoided as they have a horizontal stripe and, even when they are closed completely, the shine on the curved surfaces can make a striped pattern. 

       A coloured reading lamp may be useful. Task lighting is generally better than bright fluorescent overhead lighting.


Social factors

       Staff should be informed about the symptoms and implications of visual stress and ways to help.

       Avoid embarrassing students by questioning them about the use of overlays coloured paper or precision tinted lenses.

       Avoid asking students to read aloud in class if they find it embarrassing.

       If appropriate (and with full agreement of the student), explain overlay use to peers. 

       Visual stress interferes with sustained work and causes rapid fatigue. A child/young person should be advised how to break tasks into manageable sections, and how to plan rest breaks.

Visual difficulties may have a detrimental effect on self-esteem and the acquisition of literacy skills and subject knowledge. 

Sympathetic treatment and support is needed.


Precision tinted lenses:

       Sustained use of an overlay or sufficient increase in reading speed may indicate the potential benefit of precision tinted lenses. These are not available on the NHS but should always be prescribed by an appropriately trained eyecare professional.

Optometrists in the UK who offer this service are listed on the Cerium site. Some are members of the Society for Coloured Lens Prescribers and are signatories to a code of conduct. They may be contacted via the Society’s site