Take the colour test

Op­ti­cian He­len Hil­lis ex­plains the think­ing be­hind tests for lev­els of colour vi­sion prob­lems.

Let's Talk - - Health -

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 let­stalk@archant.co.uk, 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.

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