Take the colour test
Optician Helen Hillis explains the thinking behind tests for levels of colour vision problems.
If you read last month’s article you should remember I was hunting around for my dissertation on colour vision. (It’s still in that very safe place which my brain has forgotten about!) However, I promised I would continue on the subject of colour vision.
So why would an optometrist check your colour vision? Well, routinely I check the colour vision of customers on their first visit to the practice. This is extremely important on a child’s first eye examination.
Early years education often uses colour recognition as a learning tool. If a child has difficulty in recognising some colours, it is useful for their teacher to be aware, so that this doesn’t affect the child’s early education. The two colour vision tests I use in practice for checking children’s colour vision are the Matsubara Colour Vision Test and the Ishihara Colour Vision Test.
The Matsubara Colour Vision Test is used for pre-school children and infants; it is a series of pictures hidden in coloured dots. These pictures are easy for young children to recognise, ie flower, dog and butterfly. For school children we use the Ishihara test, which you will recognise from the picture, above. It is a serious of numbers hidden in coloured dots.
Some numbers will be seen by everyone, others will only be seen by those with colour vision problems, and some of these even indicate how strongly colour blind an individual is.
Optometrists also screen teenagers for colour vision problems, before they enter certain courses at college, for example an electrician’s course. Some colleges need a signed form from an optometrist indicating that the teenager has passed the colour vision test before they can start their course.
We also work with industries such as the fire service and aviation authorities. These industries often need the individual to be tested on several different colour vision tests, to find out to what severity they are colour blind. One of these tests, namely the Farnsworth D-15 Colour Vision Test, makes the individual order 15 different colours by closest match. The order placed determines what type of colour vision problem the person has and to what degree of severity.
Lots of different career paths need people to have good colour recognition skills. It is important for children, teachers and parents alike to be aware of these. This will allow them to gently steer children with colour recognition problems away from these career choices. However, many industries are changing their regulations on colour recognition depending on the severity of the problem.
If you are concerned about career choice and colour vision, chat to your optometrist about it when you next visit, you may only be mildly affected and some of the above industries may be open to you.
‘Some numbers will be seen by everyone, others will only be seen by those with colour vision problems’
Kate Fenn and Helen Hillis are directors of Coleman Opticians, 7-11 St Augustines Street, Norwich NR3 3DH; tel 01603 624564.
If you have a question about eye care send it to: Opticians, Let’s Talk Magazine, Prospect House Rouen Road, Norwich, NR1 1RE, or email email@example.com, put Opticians in the subject line.
COLOUR CHECK: Some people see a six; others don’t see anything at all.
WHAT DO YOU SEE? Most people will see 74, but some may see 21.