Effective colour blindness tests

1. Effective colour blindness tests Colour blindness is a hereditary issue in majority of people who are affected by this condition. In this type of an issue, the cone cells of the eyes are either absent or not functional, thereby causing colour-related vision issues with men and women. There are different known methods of colour blindness test. 1.Ishihara Test This test was introduced at least a century back. There are 38 plates – each of them circular in nature with the background filled with dotted colours. In the foreground, there is usually either a number or a path drawn. Each plate has at least three or more different colours. The affected person needs to identify the colours present in the plate. This method is still the most effective method of colour blindness test. People who have normal vision are able to clearly distinguish the colours while people who are colour blind will see only one colour. 2.Lantern Tests Lantern tests are mostly used as vocational tests. Since these tests were introduced by railway companies to test the colour differentiating abilities of their employees, there were many such tests that help measure the ability of the colour-blind person to see the difference between green and red lights. This shows good and convincing results for people with mild colour defect issues. There have been many versions of the Lantern tests. The Holmes-Wright test uses 2 green variants, 2 red and one single white light. The person is made to see lights in pairs of two – one in low intensity and the other in high intensity. The person is then asked to identify the colours. In the Farnsworth Lantern test, also called FALANT, the lights that are shown are red, green and yellowish white. They are shown in the vertical position. Nine colour pairs are used and the person is asked to name the colours after seeing the coloured pair for two seconds. This is a commonly used method in the UK to detect colour blindness. 3.HRR Chart Test from USA This test is used for colour blindness test for people who are affected genetically as well as those who have acquired the problem. The doctor uses 6 plates for screening and 14 plates for diagnosing the severity of the issue. These tests are used all over the globe for testing colour blindness. Colour blindness test in India are conducted at specialized clinics by expert doctors. The Colour Assessment and Diagnosis or CAD Test is quite commonly used in India. This test is slowly gaining prominence in the optical field. The test was initiated by the UK Civil Aviation Authority and US Federal Aviation Administration. The test is known for showing near-accurate results and can mark patients in six different

2. categories of colour deficiency – from supernormal to severe colour deficiency. Because of the precision of the test results of CAD, it is being used in professions like flying and aviation industry where it is critical that the pilots are tested for accurately for colour deficiency issue.