What it is
Color blindness, often called color vision deficiency, happens when the color-sensing cells in the retina (called cones) don't respond to light in the typical way. Most people have three cone types that help the brain tell reds, greens and blues apart. When one type is missing, weaker or shifted, some colors can look alike.
The most common cause is inherited. Color vision genes are passed down in families, and the genes for red and green sensitivity sit on the X chromosome. That is why red-green types, often described as protan and deutan, are more common in men. Blue-yellow types, called tritan, are less common and follow a different inheritance pattern.
Color vision can also change later in life. Acquired causes may include some eye conditions, diseases that affect the optic nerve or brain, eye injury, certain medicines or chemical exposures, and natural aging of the eye's lens. An acquired change may look different from an inherited one, and it may affect one eye more than the other.
Color-enhancing filter glasses and contact lenses are sometimes discussed in connection with color blindness. They do not cure it and do not restore normal color vision. How much they help, if at all, varies with the person's specific type (protan, deutan or tritan) and severity.
How it’s traditionally been approached
Color vision has traditionally been checked with simple screening tests, such as plates made of colored dots, or with tests that ask a person to arrange colored caps in order. These help show whether a difference exists and what general type it may be.
When a difference is found, eye care professionals have often looked at the person's history. They may ask whether it has been there since childhood, whether relatives have it, and whether anything has changed recently, such as new medicines or eye symptoms.
For inherited types, approaches have usually centered on understanding and adapting, such as learning workarounds for color-coded information or using labels and apps. For acquired types, attention has traditionally gone to the underlying condition or contributing factor. Only a licensed clinician can decide what is appropriate for any individual.
How the right doctor may help
The right provider, such as an eye doctor experienced in genetic and acquired color vision evaluation, may help you work out which kind of color vision difference you have and, where possible, why. A visit often starts with questions about your history, your family and any recent changes in your vision or health.
The exam may include color vision tests and a look at the health of your eyes. Depending on what your clinician finds, they may suggest further evaluation. Whether any testing or follow-up is needed is their decision after an evaluation.
Helpful questions to bring: Does my pattern look inherited or acquired? Could any medicine or health condition be involved? Is it likely to change over time? How might it affect school, work or licensing requirements? What do you know about color-enhancing glasses or lenses in my specific case, and what is their regulatory status? Asking these can help you leave with clearer expectations.
The whole-person view
Body, mind and stress affect each other, and vision is part of that picture. Learning that a color vision difference has a cause, or that it may have changed, can bring relief, curiosity or worry. Stress and tiredness can also make everyday visual tasks feel harder, even when the underlying vision hasn't changed.
If a new diagnosis or change brings up worry, body-based support such as that listed through Somatic Experiences may appeal to some people, and talk therapy through Therapists.plus is another option for working through the emotional side. Neither replaces an eye exam, and both are simply possibilities to explore.
Keep in mind
- Educational only, not medical advice: a licensed professional should guide any evaluation or care.
- A sudden change in color vision, especially with pain, vision loss, headache or other new symptoms, should be checked promptly by a licensed professional. For emergencies call 911.
- Color-enhancing glasses and contact lenses do not cure color blindness or restore normal color vision, and results vary by type and severity.
- If distress feels overwhelming, call or text 988 (Suicide & Crisis Lifeline). Color vision requirements for jobs and licenses vary and change, so confirm current rules with the employer or agency.
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Frequently asked questions
What are the main causes of color blindness?
The main causes of color blindness are inherited gene differences present from birth and changes that develop later in life. Later changes can relate to eye or nerve conditions, some medicines, injury or aging. An eye doctor can help work out which applies to you.
Is color blindness genetic?
Most often, yes. The common red-green types are usually passed down in families through genes on the X chromosome. Not every case is inherited, though, since some are acquired.
Why is color blindness more common in men?
Red-green color blindness is linked to genes on the X chromosome. Men have one X chromosome, so one altered gene can show up as a color vision difference, while women often have a second X that may balance it out.
Can you become color blind later in life?
Yes, color vision can change later. Possible reasons include certain eye diseases, nerve or brain conditions, injury, some medicines and natural changes in the eye with age. Anyone noticing a change should see a licensed eye professional.
Can color blindness be cured?
Inherited color blindness has no cure. Color-enhancing glasses or contact lenses do not cure it or restore normal color vision, and how much they help varies by type and severity. For acquired cases, a clinician may look at the underlying cause, and outcomes vary.
Which doctor can tell me what is causing my color vision difference?
An eye care professional, such as an optometrist or ophthalmologist, can usually start the evaluation. Some providers focus on genetic and acquired color vision evaluation. Ask what testing they use and whether further evaluation could be useful.
Educational resource. Colorblind Glasses shares general information and connects people with independent doctors. It is not medical advice, diagnosis or treatment. Talk with a licensed professional about your health.