| |
Colour blindness
Common illnesses
 Some diseases are more common among men or affect them in a different way from women. Others affect men only. Here we take a look at these, as well as the specific consequences of smoking and alcohol for men.
In this section
You may be taken to different areas of the health and relationships websites. Simply use your back button to return to the men's health section
Colour blindness is the reduced ability to distinguish between certain colours. It's usually inherited and is more common in men, affecting about one in 20. Far fewer women - around one in 200 - are affected.
What is it?
There are several forms of colour blindness. The most common form is red/green colour blindness, which involves the confusion of red and green. It's passed on through a faulty colour vision gene on an X chromosome as a recessive disorder. It has two forms:
different shades of red appear dull and indistinct
greens, oranges, pale reds and browns all appear as the same hue, distinguished only by their intensity
In one rare form of colour blindness, blues and yellows can't be distinguished. In another, all colours are seen in black and white.
Vision itself isn't affected, only the ability to distinguish between certain colours.
The Ishihara test
The image on the right shows a background of green dots with two wavy lines made up of red and orange dots. If you're colour blind, you won't be able to see these colours and so you won't be able to pick out the pattern from the dots.
This is the most common test used to diagnose colour blindness. You may also come across a version that uses one colour of dots to spell out numbers that can be read by someone with normal vision, while colour blind people only see a random pattern.
Why does it happen?
The retina of the eye has colour-detecting vision cells, called cones, which are necessary to see colour properly. There are three types of cone cell, sensitive to red, blue, or green light. If one or more of these types of cells is faulty, then colour blindness results.
Sometimes colour blindness occurs because of diseases such as macular degeneration or from side effects of medicines.
Stop signs
Colour blindness needn't stop someone driving, because traffic lights can be distinguished by the position of the light. However, it can be an obstacle to particular careers where good colour vision is important, including pilots, electricians, train drivers and some jobs in the printing, fashion and design industries.
 Can I stop it?
Not if it's inherited. If it's because of underlying eye disorders or medication then it can sometimes be treated and stopped.
Should I see a doctor?
This isn't necessary unless other eye problems, for example blurred vision, are occurring.
Treatments
As inherited forms of colour blindness are harmless, no treatment is needed.
|
|
