Sight Examinations and Assessments
Colorimeter Assessments
(Duration 40 minutes)
Tinted lenses differ from overlays and coloured paper. With these the eye is adapted to surrounding illumination, generally white or nearly white light. However, when a tinted lens is placed before the eye it becomes adapted to the colour of the light passing through the lens, which is obviously dependent upon the colour of the tint. For this reason the tint required is rarely the same as the colour effective as a background for reading and writing. Assessment with a colorimeter is required in order to determine the appropriate hue and saturation of light that will maximise the benefit of the colour effect. This is then matched with carefully dyed tint samples that can be combined to reproduce exactly those precise lighting conditions.
Coloured Overlays can be extremely helpful but are limited in their use in that they need to be placed on top of a page and cannot, therefore, be used for written work or computer work. If an individual has sustained success with a Coloured Overlay over a period of six months if might be useful to carry out a full Colorimeter Assessment in order to determine a spectacle tint that will produce the same benefit.
The Intuitive Colorimeter has been developed by the Medical Research Council to examine the benefits of colour upon reading, in fine detail and with controlled variables. The results can be reproduced accurately in the form of precision tinted lenses for mounting in spectacles.
Each patients colour requirement is unique and their precision lenses are individually made.
It should be noted that the most effective colour is not necessarily the same colour as that chosen for overlays, and the larger colour range available for lenses helps obtain the best effects.