不同类型的色盲是什么?

Color blindness is a common condition in which there is a decreased ability to see or differentiate between certain colors. This usually happens between shades of greens and reds and, occasionally, blues.

Color blindness can beinherited(present at birth) or acquired (a result of theagingprocess, eye disease or injury, and certain medications).

This condition affects males more often than females and is estimated to be found in approximately 1 in 12 men and 1 in 200 women in the world.

Color blindness is also called:

• Color vision deficiency
• Defective color vision

There are several causes of color blindness including:

• Inherited or genetic:The most common cause is mutations in theOPN1LW,OPN1MW,andOPN1SWgenes, which are inherited from parents. These mutations can cause faulty photopigments and impaired color vision.
• Acquired:Some people may become color-blind due to other causes, such as
  • Aging:The condition can be acquired over time due to the aging process.
  • Diseases:Diabetes,multiple sclerosis,glaucoma,cataract,macular degeneration, Alzheimer’s disease,sickle cell anemia, andleukemia.
  • Medications:Due to side effects of certaindrugs, such aschloroquineor drugs to treathigh blood pressure, infections, nervous, andpsychological disorders.
  • Chemicals:Can result from exposure to chemicals, such as organic solvents, carbon disulfide, and lead.
  • Alcoholconsumption:Reduced color discrimination can be a symptom ofalcoholism.
  • Physical cause:Damage ortraumato theoptic nerveor parts of the brain.

The symptoms of color blindness can range from mild to severe, including:

• Trouble seeing or differentiating shades of colors
• Inability to differentiate brightness of colors

In rare cases, people can see only in shades of gray called achromatopsia, which is a condition often associated with:

• Nystagmus (rapid, uncontrollable eye movements)
• Light sensitivity
• Amblyopia (lazy eye)
• Poor vision

Based on the symptoms, the ophthalmologist will conduct simple tests to determine if a person has color blindness.

• Color vision test or Ishihara color test:Contains 38 plates of circles created by irregular colored dots in two or more colors.
• Cambridge color test:Patients are told to find a “C” shape that is in a different color than the background on the computer screen.
• Anomaloscope:Used to measure quantitative and qualitative anomalies in color perception.
• Farnsworth-Munsell 100 hue test:Uses blocks or pegs of different shades of the same color.

Currently, there are no medical treatments available for color blindness.

People with this condition learn to adapt and live with a relatively minor inconvenience. However, special glasses or corrective contact lenses may help people with red-green deficiency.

Treatment of the underlying medical condition may help resolve color vision deficiencies.