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How can colour blindness be tested?

Colour-blindness is a condition in which certain colours cannot be distinguished. It is congenital and permanent. Red/green colour blindness is by far the most common form and 99% of people who are colour blind have this form. It is usually hereditary and occurs most often in males. There is no treatment for colour blindness but it doesn’t usually cause any significant disability. It can however be very frustrating for individuals who are affected by it.
Colour vision can be tested in many different ways but the most common is the Ishihara test. In this test the optician shows the patient a number of plates which are printed with dots of varying colour, brightness, density, and sizes arranged so that the dots of one colour form a number among a background in another colour. If a person is colour blind, they will be unable to identify some, or all, of the figures hidden in the dots.
Particularly if there is a history of colour-blindness in your family, you should make an appointment with an ophthalmologist as identifying the problem can make a huge difference to your life. 

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