What are color vision disorders?
Complete color blindness, where the world is perceived in shades of gray, is extremely rare. Usually we are talking about a partial violation: the sensitivity of one of the types of cones is reduced or this type is absent. With red-green disorders, a person confuses red with brown and green and has difficulty distinguishing shades in this range, especially in low light. Blue-yellow disorders are less common and are more often acquired. People with congenital color blindness do not see the world in black and white: they distinguish most colors, but some shades merge for them.
- Protanopia and protanomaly - red disorders
- Deuteranopia and deuteranomaly - in green
- Tritanopia - a rare blue disorder
- Achromatopsia - complete absence of color vision, very rare
- Acquired forms in diseases of the retina and nerve
Why it occurs and how it is inherited
Congenital red-green color blindness is associated with genes located on the X chromosome. Men have one X chromosome, so the altered gene is immediately manifested; in women, a second healthy X chromosome usually compensates for the defect, and they are more often carriers. Hence the well-known pattern: the trait is passed on from grandfather through daughter to grandson. Acquired color vision disorders occur with diseases of the optic nerve and retina, cataracts, glaucoma, diabetes, and also as a side effect of certain medications.
- X-linked inheritance
- Men are affected significantly more often than women
- Women are more likely to be carriers of the gene
- Acquired forms of neuritis and optic nerve atrophy
- Age-related changes in the lens
- Side effects of certain drugs
How does it manifest itself?
Congenital color blindness usually does not interfere with everyday life, and a person does not know about it for a long time: since childhood, he names colors as he was taught. Clues include difficulties in distinguishing between ripe and unripe fruits, confusion in the colors of wires and graphs, and difficulties with traffic signals in poor visibility. A child may color familiar objects incorrectly. Acquired disorders feel different: colors “fade”, often in one eye, and this is accompanied by other vision complaints.
- A confusion of red, green and brown
- Difficulty with color graphs and diagrams
- Difficulties in choosing ripe fruits
- The child colors pictures in an unusual way
- Fading of flowers in acquired form
- Difference in color perception between eyes
How color vision is tested
The main method is polychromatic tables, on which numbers and figures are made up of colored dots: a person with normal color vision sees some images, a person with impaired color vision sees others, or sees nothing. The test is carried out in good daylight, each eye separately, without colored lenses. To accurately determine the type and extent of the disorder, an anomaloscope and tests with sorting of color samples are used. If the disorder did not appear in childhood, be sure to examine the fundus of the eye, check the field of vision and, if necessary, refer to a neurologist.
- Polychromatic tables
- Checking each eye separately
- Anomaloscope to determine the type of violation
- Color Sorting Tests
- Examination of the fundus in the acquired form
- Perimetry and consultation with a neurologist according to indications
Living with colorblindness
A congenital disorder cannot be treated and does not progress, so the main task is adaptation. The habit of focusing on the position of the traffic light rather than the color, marking things with captions, and using color-determining applications and contrast settings on screens help. There are glasses and lenses with filters: they do not restore color vision, but for some people they help to better distinguish individual shades. The restrictions apply to professions where color is critical to safety; the requirements for drivers and a number of professions are clarified by the medical commission.
- Focus on position, not signal color
- Signatures and markings instead of color codes
- Color Recognition Applications
- Adjusting screen contrast
- Filtering glasses as an aid
- Clarification of professional requirements at the medical examination
