For many, coloured overlays make reading easier. When the correct colour is placed over reading material there is an immediate reduction in the glare of the white page and the contrast of the black text on white paper. In addition, the pattern of the text and the letters is altered so it no longer triggers perceptual distortions. The result is a page that is easier to look at, and thus easier to read.  


Opticalm carries a wide selection of overlay colours from several suppliers to provide a full range of options to meet our client’s needs.  See our "About Overlays" section for more information.

Crossbow ruler overlays: Single colour – Pack of 4

  • Crossbow Education reading rulers are a very popular item in UK schools. Over 60% of the schools have them as standard tools in the teacher’s toolbox.  They are small and a great way to try out colour to see if it is effective before purchasing the larger sized overlay. 


    This set of 5 rulers is great for allowing you to have them for home, school and work.   


    Formally designed by visual stress specialists and researchers, the colours are moderately saturated and evenly spaced around the colour spectrum to provide enough options for readers to choose from.  


    Reading rulers can be used on their own, doubled for deeper saturation, or paired with neighbouring colours to provide even more colour options.  Stringent testing ensures that the overlays are clear and print clarity is retained. 


    While reading rulers are smaller and easier to stow away in a book, they are not as effective as a full page overlay as they do not cover all the white space that is often a trigger to discomfort and distortions. 

Opticalm Visual Stress Clinic

160 Terence Matthews Cres., Suite A1, Main Floor

Kanata ON K2M 0B2

Tel: 613-294-6437

Fax: 613-254-9206

By appointment only

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