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Colour vision tests

U2.9.3 Colour vision tests (2017)

The query for this month was from a member about colour vision testing: could a dispensing optician carry out the Ishihara test legally?

The testing of colour vision usually takes place during an eye examination. It is an important test for both clinical and practical reasons. The clinical reasons are that it can be indicative of pathology, or changes in pathology, and the practical reasons are that a colour vision defect would prevent employment in certain fields and affect the patient’s safety in some circumstances.

It has been suggested that a registered dispensing optician might conduct such a test outside an eye examination, perhaps as part of a pre-screening process or at the request of a patient needing the information for a job application. If the dispensing optician has been trained in the use of Ishihara plates, such a test could reasonably be carried out by them.

The result, if normal, could then be given to the patient. However, if the result was not normal, a referral to an optometrist would be necessary to clarify the finding with other tests less stringent than the Ishihara plates. It might also be necessary to rule out any underlying pathology.

If colour vision has been recently checked within the practice and recorded as normal, that information may be passed on to the patient, or the patient’s parents, by the registered dispensing optician. If the result was not normal, that information might also be passed on to the patient with an appropriate explanation and further referral if necessary.