Color Blindness: Types, Causes, Symptoms, Diagnosis and Treatment

Color blindness is the condition in which part of the cones (nerve cells) in your eyes are absent or malfunctioning, making it impossible for you to perceive colors normally.  you may have problems differentiating between certain colors or shades, as well as recognizing color brightness. Most cases of color blindness are inherited as a result of a genetic mutation.

What does color blindness mean?

Your eye doesn't see color the way it should if you are color blind.

 A rather frequent disorder in which you don't see colors in the conventional sense is color blindness, also known as color vision deficit. This is the result of malfunctioning cones, a particular kind of nerve cell found in the retina of your eye. As light and images enter your eye, cones process them and send signals to your brain that allow you to perceive color.

It's rare that color blindness results in complete color blindness. While most color-blind individuals see a wide spectrum of colors, their perception of some colors is different from that of others. Additionally, they could find it difficult to differentiate between certain colors or shades. A person who has some extremely rare forms of color blindness is completely colorblind.

Color blindness is inherited in most cases. This indicates that, in the case of the most prevalent red-green types of color blindness, it was inherited from your biological parents, specifically the mother. But later in life, medical conditions or other factors may potentially cause you to develop a color vision deficit.

It's important to understand the type and severity of color blindness if you or your child suffers from it. See an optometrist or ophthalmologist for eye care information on the nature of the condition and your potential risks.

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Types of color blindness and the range of visual perception:

Several types of color blindness are identified based on the types of cones that don't work properly. A basic understanding of cones is helps understand different types of color blindness.

Your eye's cones are nerve cells that identify colors in the visible light range. All of the visible wavelengths to humans are included in this spectrum. These vary in length from 700 nanometers (long) to 380 nanometers (short), or nm. You typically have three types of cones at being born:

• Cones that sense red (also known as L cones) can detect long wavelengths or about 560 nanometers.

• M cones, or green-sensing cones, are cones that detect light in the middle wavelength range, or about 530 nanometers.

• Cones that sense blue (also known as S cones) can detect short wavelengths, about 420 nanometers.

All three forms of cones are commonly found and function as intended. However, at least one kind of cone isn't functioning properly if you have a color vision impairment. Your ability to perceive colors in the conventional sense is compromised by cone problems. Generally speaking, the following categories characterize the variety and effectiveness of cones you have:

Trichromacy: There are three distinct types of cones and they are all functional. In the conventional sense, you can see every color in the visible spectrum of light. This is a vision in full color.

 Anomalous trichromacy: When one of the three types of cones you have isn't responding to light at its proper wavelength, this is known as anomalous trichromacy. You see colors differently as a result, with variances from normal ranging from little to severe. In minor circumstances, you can just confuse muted or faint hues. More extreme situations may also lead to confusion between pure and vivid (fully saturated) colors. The terms for these types of color blindness end in "anomaly," which indicates partial vision of a specific color.

Dichromacy: There is a lack of one type of cone. There are only two types of cones, which are often S cones and either L cones or M cones. Through the wavelengths that those two types of cones can detect, you view the world. Differentiating between fully saturated colors is difficult. The term "anopia" (which denotes the absence of a vision of a particular color) ends the names of several types of color blindness.

Monochromacy: The presence of only one type of cone or the complete absence of cone function. You see color with very little or no ability at all. Rather, you perceive the world via a spectrum of shades of gray.

There exist numerous distinct varieties of color blindness within these general categories.

 Red-green color deficiency:

The predominant type of color blindness is known as the red-green color deficit. It alters your perception of any colors or shades that contain some red or green. Four primary subtypes exist:

Protanopia: You don't have any L cones. You therefore cannot see red light. Most colors appear to you as variations of blue or gold. It's easy to mistake different shades of red for black. Dark brown can also be mistaken for deep hues of other colors, such as orange, red, or green.

Deuteranopia: There are no M cones on your body. You therefore cannot sense the green light. Most of what you see is blue and gold. Certain shades of red can be mistaken for some shades of green. Yellows can also be mistaken for vivid shades of green.

Protanomaly: Your L cones are less sensitive to red light than they should be, even though you have all three types of cones. Every color that incorporates red can appear less brilliant and red itself may seem as dark gray.

Deuteranomaly: Although you have all three cone types, the sensitivity of your M cones to green light is not as high as it should be. Most of the colors you see are muted, especially blues and yellows.

 Dichromacy is exemplified by protonopia and deuteranopia.  examples of anomalous trichromacy are propanomaly and deuteranomaly.

You may also hear the phrases "deutan" and "protan." The abbreviations proton and deutan are used to refer to red-green colorblindness. Deutan means green (you lack or have damaged M cones, which are green-sensing cones). Red is referred to as proton (you lack or have damaged red-sensing cones or L cones).

red-green color blindness Compared to women and those assigned female at birth (AFAB), red-green color blindness is far more common in men and those assigned male at birth (AMAB). This is because males have one X chromosome and females have two, which contain the genes for the color vision cone light-sensitive proteins. Therefore, color blindness can reveal itself in males whose one X chromosome has abnormal genes, but females can make up for it with the other normal gene on the second X chromosome.

 Blue-yellow color deficiency:

Tritan deficits, often known as blue-yellow color vision defects, are far less prevalent and include:

Tritanopia: You don't have any S cones. Thus, blue light is invisible to you. Mostly, you're seeing reds, pinks, lavender, and light blues.

Tritanomaly: Your S cones are less sensitive to blue light than they should be, even though you have all three types of cones. Greenish-blue colors look to be devoid of yellow.

AMAB and AFAB people are equally affected by blue-yellow color blindness.

Monochromacy in blue cones
The rarest type of color blindness is this one. You cannot use M or L cones with this type of device. All you have are S cones. It's hard to tell the difference between colors because the majority of what you see is gray. In addition, you can experience nystagmus, nearsightedness, and photophobia—a sensitivity to light.

Achromatopsia, or rod monochromacy
When all or most of your cones are missing or malfunctioning, you have achromatopsia. Everything seems to be in shades of gray. Your quality of life may be greatly affected by other vision issues you have.




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What causes color blindness?

Color blindness can be acquired (occurs later in life) or inherited (present at birth). Every case has a different cause.

Causes of inherited color blindness
A genetic mutation results in inherited color blindness.

Red-green color blindness, the most prevalent type, is inherited recessive via an X-linked mechanism. Such hereditary conditions are uncommon in babies with AFAB and typically affect babies with AMAB. This is an explanation of red-green color blindness's inheritance.

A baby boy:

if the mother has red-green color blindness, will inherit the condition.
carries one copy of the genetic mutation but does not have red-green color blindness, so there is a 50% chance that the child will inherit the condition. The 50:50 chance results from the other copy being normal.

won't inherit the condition if just the father has it because male children receive the Y chromosome, while female babies receive the X chromosome.

A baby girl:

will receive red-green color blindness as an inheritable condition if both parents are affected.
If the mother does not have the condition and is not a carrier, then the father will be a carrier.
If the mother is a carrier and the father has the condition, the child will either inherit red-green color blindness (50% probability) or be a carrier (50% chance).

Causes for acquiring color blindness:

There are numerous potential reasons for acquired color blindness, which often manifests as a blue-yellow color deficiency. Among them are:

• Exposure to chemicals that can harm your nervous system, such as heavy metals, organic solvents, and solvent mixtures.
• Long exposure to lights used in welding.
• Medications, such as hydroxychloroquine (for the treatment of rheumatoid arthritis).
• Conditions of the eyes, such as cataracts, glaucoma, and age-related macular degeneration.
• Conditions that impact the nervous system or brain, such as multiple sclerosis (MS), diabetes, and Alzheimer's disease.
• Compared to inherited types, acquired color blindness is less common.

What symptoms of color blindness are present?

If you have difficulties, you may have a form of color blindness.

However, you must know where to look for these indications to identify them. Because they have always seen colors in the same way, many people who are color blind are unaware of the need to look for these differences. So, people remain unaware of any changes to their color vision.

For this reason, before they start attending school, children should receive a thorough eye examination that includes colorblind testing. Color is frequently used in exams and other educational materials to convey information or measure students' progress. Children who have different color perceptions could find these products difficult.

The following are symptoms of this eye syndrome:

• Rapid eye movement.
• The sensitivity to bright light.
• Problems with color perception and hue brightness.
• The challenge of differentiating between color shades.

How can color blindness be diagnosed?

Color blindness is diagnosed by eye care professionals using a variety of tests.

The most popular test used by eye care professionals to diagnose red-green color blindness is the Ishihara test. A supplier shows you a sequence of color plates for this test. There is a pattern of small dots on each dish. There is a number (or shape, for younger children) among those dots. You label the items on each dish that you can see. There are some plates with numbers that are only visible with full-color vision. Others have numbers that are only visible to those who are color-blind.

Your provider can suggest additional testing to confirm a diagnosis and gather more information based on the results of the Ishihara test.

Make an appointment for an eye examination with an eye care professional if you think you or your child may be color blind. Make sure to bring up your concerns when you have your appointment.

At what age is my child appropriate for colorblind testing?
Testing for color vision deficiencies is usually appropriate for children four years old and up. Most 4-year-olds can respond to inquiries about what they observe. But your child ought to get their first thorough eye test much earlier (before turning one year old).

What color blindness treatments are available?

For those who have inherited color blindness, there is currently no known medical cure or treatment. If you develop color blindness, your doctor will address the underlying issue and change your prescription as necessary. This could help you see color more clearly.

 you may have heard of colorblind glasses. When using such glasses, those with modest forms of anomalous trichromacy may enjoy a richer color perception. People with color vision deficiencies can see differences more clearly thanks to the glasses, which increase the contrast between colors. However, they don't let you see any new colors, and each person's experience will be different. Furthermore, it's important to know that these glasses won't fix any problems with your cones and aren't a treatment.

See an eye doctor to find out if color-blindness glasses are necessary before making the decision.

This syndrome has no known treatment at this time. To enhance the depth between particular colors, one can somewhat use contact lens glasses and photographic frames or filters. The symptoms of color blindness can be lessened by eating a diet that is properly balanced.

Individuals suffering from color blindness encounter many difficulties in their daily live. They might struggle to distinguish between different types of pulses, choose from a wide variety of fresh produce, fruits, and flowers, drive, shop, and much more. Red and green color blindness is the most prevalent kind of hereditary color blindness. Studies and medical records indicate that men are more likely than women to be affected by red and green color blindness. Blue color blindness affects women and men equally.

Prevention:

Color blindness that is inherited cannot be prevented. You might be able to reduce your chance of developing acquired color blindness, though. Ask your healthcare practitioner about your risk of acquiring color vision deficiencies when you visit them for your annual exam. Among the inquiries to make are:

• Do any of my medical conditions increase my chance of developing color blindness?
• Can color blindness be caused by any of my medications?
• Is there anything to worry about in terms of environmental or chemical exposure at work?
• How can I lower my risk?

References:

• American Academy of Ophthalmology. What Is Color Blindness? (https://www.aao.org/eye-health/diseases/what-is-color-blindness) Accessed 3/17/2023.

• Birch J. Worldwide prevalence of red-green color deficiency (https://pubmed.ncbi.nlm.nih.gov/22472762/). J Opt Soc Am A Opt Image Sci Vis. 2012;29(3):313-320. Accessed 3/17/2023.

• U.S. National Library of Medicine. Color Vision Deficiency (https://medlineplus.gov/genetics/condition/color-vision-deficiency/). Accessed 3/17/2023.

• Fanlo Zarazaga A, Gutiérrez Vásquez J, Pueyo Royo V. Review of the main colour vision clinical assessment tests (https://pubmed.ncbi.nlm.nih.gov/30361001/). Arch Soc Esp Oftalmol (Engl Ed). 2019;94(1):25-32. Accessed 3/17/2023.

• U.S. National Eye Institute. Color Blindness (https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/color-blindness). Accessed 3/17/2023.