A color vision test, also known as the Ishihara color test, measures your ability to tell the difference among colors. If you don’t pass this test, you may have poor color vision, or your doctor may tell you that you’re color blind. However, being truly color blind is a very rare condition in which you’re only able to see shades of gray.
A colour vision test, also known as the Ishihara colour test, measures your ability to tell the difference among colours. If you don’t pass this test, you may have poor colour vision, or your doctor may tell you that you’re colour blind. However, being truly colour blind is a very rare condition in which you’re only able to see shades of grey.
The main symptom of colour blindness is a difficulty in distinguishing colours or in making mistakes when identifying colours. If a child is suspected of being colour blind the main clues to look out for are:
- Using the wrong colours for an object – e.g. purple leaves on trees, particularly using dark colours inappropriately
- Low attention span when colouring in worksheets
- Denial of colour issues
- Problems in identifying red or green colour pencils or any colour pencil with red or green in its composition. (e.g. purple, brown)
- Identification of colour may be made worse by low level light, small areas of colour and colours of the same hue
- smelling food before eating
- Excellent sense of smell
- Excellent night vision
- Sensitivity to bright lights
- Reading issues with coloured pages or work sheets produced with colour on colour
- Children may complain that their eyes or head hurt, if looking at something red on a green background, or vice versa
The most common type of poor colour vision is an inability to distinguish shades of green from red. Poor colour vision can be caused by:
- Certain medications and diseases
- Exposure to chemicals
Sometimes, problems with colour vision are due to a disease affecting your optic nerve, such as glaucoma. Poor colour vision can also be the result of an inherited problem with the cones (colour-sensitive photoreceptors) in your retina.
Certain diseases can cause colour vision impairment, including:
- Macular degeneration
- Alzheimer’s disease
- Parkinson’s disease
- Sickle cell anemia
How to Identify?
A colour blind test is a device your eye doctor uses to determine if you have a colour vision deficiency, commonly known as colour blindness. There are two types of colour blind tests:
- Screening tests that can detect the presence of a colour vision problem (Ishihara Color Vision Test.)
- More detailed, quantitative tests that can detect a colour vision deficiency and determine the type and severity of colour blindness
- Online colour blind tests that variations of the Ishihara screening test and are presented in varying degrees of quality.
- See an eye doctor.
A colour blind test should be given to anyone considering a profession where accurate colour perception is essential. The effect colour blindness has on a person's job performance depends in large part on the colour-related requirements of the position and the severity of the person's colour vision deficiency. In many cases, fears about being handicapped by colour blindness are unwarranted. Because the condition is present at birth, most colour-blind people are unaware of their colour vision deficiency and do not find that it interferes significantly with their daily lives.
What to Do?
There is no cure for inherited colour deficiency. But if the cause is an illness or eye injury, treating these conditions may improve colour vision. Using special tinted eyeglasses or wearing a red-tinted contact lens on one eye can increase some people's ability to differentiate between colours, though nothing can make them truly see the deficient colour. Most people with colour vision deficiency find ways to work around the inability to see certain colours by:
- Organizing and labelling clothing, furniture or other coloured objects (with the help of friends or family) for ease of recognition.
- Remembering the order of things rather than their colour.