Colour vision deficiency (CVD) is often mistakenly called ‘colour blindness.’ CVD is fairly common, affecting around 8% of Australian males and around 0.5% of females. Most commonly it is a genetic condition that can run in families. Abnormal colour vision may vary from not being able to distinguish between certain shades of colour to not being able to identify colour at all.
What causes colour vision deficiency?
Receptors in the retina at the back of the eye send signals to the brain via the Optic Nerve to be interpreted as sight. There are two types of receptors – Rods and Cones. Rods work best in low light levels, found in the outer regions of the retina and help with our night and side vision. They are not colour sensitive.
Cones are concentrated mainly in the small area called the Macula, which also gives us our central, detailed vision. There are three types of Cones responsible for the colour signals, each containing a different pigment, and they are activated when the pigments in them absorb light.
The different kinds of CVD result from one or more of the different cone systems either not functioning at all, or functioning in an unusual way. The most common forms of CVD result from problems with either the middle or long wavelength sensitive cone systems and involve difficulties in discriminating the reds and greens and all the various shades of these colours.
How do you test for CVD?
Our testing procedure involves first determining the type and degree of deficiency. We do this with various methods including computer based tests that each person will perform themselves. The time taken will vary but we always allow at least one hour, since after the correct lens is determined the person will wear the lenses to see how they change and enhance their world of colours. We also encourage each person to bring along a family member or someone close to them to observe the test, as this is the defining moment when true colours are seen for the first time. Many questions can arise and it is a great time to share.
What do you recommend?
After the analysis procedure, if you are happy with the results, a pair of IRo lenses will be ordered for you. IRo lenses are not a cure for colour vision deficiency but rather an effective colour corrective lens – in much the same way as glasses generally don’t cure your vision deficiency but can allow you to see better. These lenses are by far the best quality lenses to treat CVD. They give a truer perception of the colours and are very durable.
Rosser Optometry is the only Colourblind Sight Centre on the Gold Coast. Book in for a colour vision assessment and let us make your world a brighter place!