color vision problems are inherited (genetic) problems
cone cells in the eye. These are the cells that make you able to see color. Inherited color
vision problems affect both eyes equally, are usually present at birth, and do
not change during a person's life.
The most common color vision problems are inherited problems that
make it harder to see red or green, so it becomes difficult to distinguish
between shades of these two colors. This type of problem affects about 8% of
males and less than 1% of females. A rare type of inherited problem that
affects the way a person sees blue and yellow shades occurs equally in men and
Quick! Put your hands on your head. Are your glasses there? Grab your neck — are they dangling there? Now, hold your electric bill four feet from your face and try to read it....
Welcome to the midlife version of Simon Says, a nearly universal condition known as presbyopia, which translates roughly to "elderly eye" (as if crow's feet weren't enough). It usually starts in your early 40s, as the lens of the eye stiffens, losing its ability to focus and making it difficult to see objects...
There are four main types of inherited color vision
The most common type of color vision problem, called
anomalous trichromacy, occurs in people who have all
three types of cone cells (for seeing red, green, or blue) but are missing or
have an abnormal amount of one type of cone cell, or one type has a flaw in the
pigments that the cone cells use to sense color.
People with this type can see all three
colors-red, green, and blue-but not as well as people with normal color vision.
That is, they see different shades of colors than people who have normal color
The most common color vision problem is trouble seeing red
and green. This problem varies greatly from person to person. Some people have
only a little trouble seeing red and green, and they may not even know that
they have a color vision problem. Other people may have a very hard time seeing
red and green.
Another type of color vision problem, called dichromacy, occurs when one of the three types of cone cells
is missing. That is, a person can only see two of the three colors.
Most people with this color vision problem can
tell the difference between blues and yellows but have trouble seeing reds and
greens. (A very few people in this category can see reds and greens but not
blues and yellows.)
People with this type of problem have more
serious color vision problems compared with the first type (anomalous
The third type of inherited color vision problem, called
blue-cone monochromacy, occurs when two of the cone
cells (red and green) are missing.
This problem mainly affects boys and
Distance vision is often poor, and boys with this condition
may have shaky eyes (nystagmus).
A boy or man with blue-cone
monochromacy relies only on his blue cones for color vision.
The fourth main type of inherited color vision problem, called
achromatopsia, occurs when all three types of cone cells
A person with this color vision problem cannot
see any color, only shades of gray, black, and white.
have this type of color vision problem may also have other vision problems,
such as poor distance and reading vision and sensitivity to light
This type of color vision problem is the rarest and
This is also called rod monochromacy, because the
person must rely on the eye's rod cells for vision.
Genetics of inherited color vision problems
Most color vision problems are inherited flaws in the
genes that control the production of the cone pigments
cone cells in the eye that see color.
The genes for the cone cells involved in seeing red and green
colors are on the X chromosome. Females have two X chromosomes. Males have only
one X chromosome and a Y chromosome, and they receive their X chromosome from
A male will have a red/green color vision
problem if the flawed gene is on his single X chromosome. A female must have
the flawed gene on both X chromosomes to cause color
vision problems, and this happens much less often.
A woman who is
carrying a gene for this type of color vision problem has a 50% chance of
passing it on to her sons (because they will receive one of her two X
chromosomes). Her daughters will have the color vision problem if they receive
the flawed gene on the X chromosome from both the mother and the father. This
is much less likely to happen.
A woman may carry the gene for
red/green color vision problems without being affected but may pass the gene on
to her children. This is why a color vision problem may "skip" a generation in
families that have a history of color vision problems.
The genes for the cone pigments involved in seeing blue colors are
not on the X chromosome but on a non-sex chromosome that both males and females
have. This means blue color vision problems occur equally often in males and
females. But these types of color vision problems are relatively rare.
Chang DF (2008). Color vision testing section of Ophthalmologic examination. In P Riordan-Eva, JP Whitcher, eds., Vaughan and Asbury's General Ophthalmology, 17th ed., pp. 46-59. New York: McGraw-Hill.
Primary Medical Reviewer
Adam Husney, MD, MD - Family Medicine
Specialist Medical Reviewer
Christopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
July 22, 2011
WebMD Medical Reference from Healthwise
July 22, 2011
This information is not intended to replace the advice of a doctor.
Healthwise disclaims any liability for the decisions you make based on this