Colour Vision
August 18th, 2017
Overview
Ishihara plates are coloured sheets used to test for colour vision defects including protanopia or deuteranopia. By asking the patient to read the numbers from Ishihara plates it is possible to determine the type of colour visual defect that is present.
Interpretation
- Transformation pattern plates - a different number is visible to those with a colour vision defect compared to those with normal vision.
- Vanishing digit plates - the number is visible to those with normal vision but not visible to those with a colour vision defect.
- Hidden digit plates - the number is visible to those with a colour vision defect but not visible to those with normal vision.
- Differentiation plates - a different number is visible to those with protanopia compared to those with deuteranopia.
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