Parents must-have | Is your child color blind? Take the test

Our eyes allow us to enjoy the infinite charm of the seasons;

But not everyone can feel

Such magical changing colors.

Color blindness and color weakness

It is a common color vision disorder.

And patients usually don't notice...

Causes of color blindness and color weakness

Rods and Cones

The retina of the human eye has two types of sensory cells: rods and cones. Rods mainly help us distinguish light and dark contrasts, while cones are responsible for our color perception.

People with normal vision have three types of cones, each responsible for a different range of colors: L cones for red, S cones for blue, and M cones for green. L, S, and M represent the range of the color spectrum that each type of cone is responsible for: L stands for "long" wavelengths, S stands for "short" wavelengths, and M stands for "medium" wavelengths.

The wavelengths of light entering the eye stimulate the pigments in the cones, which trigger different color perceptions in the brain. If a certain type of cone doesn't function correctly or doesn't function at all, it limits our ability to perceive color, leading to color impairment or color blindness. Cones also only work at certain levels of brightness. When it's dark, only the rod system, which is responsible for the contrast between light and dark, works. This is why contrast is reduced in the dark.

Types of color blindness

Not all types of color blindness are the same. Depending on the cause and symptoms, they are divided into color weakness, partial color blindness and complete color blindness. Color vision disorders can be congenital or acquired.

Color blindness

Color deficiency is red-green color deficiency, and people with color deficiency can only perceive certain colors because some of the sensory cells, the cones, do not function properly. There are different types of color deficiency. The most common type is red-green color deficiency, which is often mistaken for red-green color blindness or color blindness. There are two types of red-green color deficiency: difficulty in recognizing green (deuteranomaly) and difficulty in recognizing red (protanomaly). Compared with people with normal color vision, people with deuteranomaly see green as less three-dimensional and less vivid.

Partial color blindness

Partial color blindness is red-green color blindness. If you have partial color blindness, it means that some of the sensory cells responsible for perceiving colors do not exist or are not functioning. People with dichromatic vision (dichromatic) have only two types of cone cells, while people with total color blindness (monochromatic) have only one. These people cannot perceive the entire color spectrum and can only recognize specific colors.

For example, people with deuteranopia have no green cones, and people with tritanopia have no blue cones. People with protanopia lack red cones. As a result, they can only discern a limited color spectrum. These people cannot distinguish red and green at all. They don't notice traffic signs or recognize the red brake lights of the car in front of them - or they see them too late. Partial color blindness cannot be cured.

Complete color blindness

Complete color blindness is usually hereditary color blindness, in which the person can only see shades of gray, not colors. It affects men and women equally. People with complete color blindness have significantly poor vision and are very sensitive to light (photophobia). People with complete color blindness do not have any of the three types of cone cells that are responsible for color perception. Their vision relies entirely on the rod cells in the eye, which are the cells that detect light and dark. Therefore, a person with complete color blindness can distinguish about 500 different shades of light and dark. Complete color blindness is most often hereditary, but it can also be caused by a stroke, trauma, or other brain injury.

Conducting the Test

Pseudoisochromatic test, this test is suitable for diagnosing red-green color deficiency or blue-yellow color deficiency (tritanomaly). The color map consists of dots of different colors, in which specific numbers are hidden. The color vision recognition ability of the test subject is tested by reading these numbers.

For example, on the same color chart, a person with normal vision sees 74, while a person with red and green color deficiency sees 21. This method can reliably diagnose whether the test subject suffers from a specific color deficiency.

What do you see in the following color pictures?

(Hint: You can use paper and pen to record what you see in order. The correct answer is at the end!!!!)

The answers from top to bottom are: 74, 45, no result, 42, 29, no result, 5, 12, 6

If the answers you see are different from the answers below the color chart, you may have color deficiency. See a regular eye doctor for an exam. Your eye care professional can use special tests to determine if this is the case and confirm which type of color deficiency you have.

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