Color Vision: What is it?
Color Vision, is an ability to perceive differences between light composed of different wavelengths independently of light intensity.
Color perception is a part of the larger visual system and is mediated by a complex process between neurons that begins with differential stimulation of different types of photoreceptors by light entering the eye.
Color helps us remember objects, influences our purchases and sparks our emotions. But did you know that objects do not possess color? They reflect wavelengths of light that are seen as color by the human brain.
The visible spectrum for humans falls between ultraviolet light and red light. Scientists estimate that humans can distinguish up to 10 million colors.
When light hits an object, such as a lemon, the object absorbs some of that light and reflects the rest of it. That reflected light enters the human eye first through the cornea, the outermost part of the eye. The cornea bends light toward the pupil, which controls the amount of light that hits the lens. The lens then focuses the light on the retina, the layer of nerve cells in the back of the eye.
Color Vision: How does it work?
Structure of retina-rods and cones. Cones Influence Color Perception.
Our retina has two different types of cells that detect and respond to light—rods and cones. These cells that are sensitive to light are called photoreceptors. Rods are activated when we are in low or dim light. Cones are stimulated in brighter environments. Most of us have about 6 million cones, and 110 million rods.
Cones contain photo pigments, or color-detecting molecules. Humans typically have three types of photo pigments—red, green and blue. Each type of cone is sensitive to different wavelengths of visible light.
In the daytime, a lemon’s reflected light activates both red and green cones. The cones then send a signal along the optic nerve to the visual cortex of the brain. The brain processes the number of cones that were activated and the strength of their signal. After the nerve impulses are processed, you see a color— in this case, yellow.
In a darker environment, the light reflected by the lemon would stimulate only the eyes’ rods. If only the rods are activated, you don’t see color, just shades of gray.
Our past visual experiences with objects also influence our perception of color. This phenomenon is known as color constancy.
Color constancy ensures that the perceived color of an object stays about the same when seen in different conditions. For example, if we looked at a lemon under a red light, we likely would still perceive the lemon to be yellow.
What are the most common Color Vision Anomlies?
Color blindness (Achromatopsia) can occur when one or more of the cone types are not functioning as expected. Cones can be absent, nonfunctioning or detect a different color than normal. Red-green color blindness is the most common, followed by blue-yellow color blindness. Men are more likely to have color blindness than women. Scientists are currently developing new treatments for color blindness.
Researchers estimate that up to 12 percent of females have four cone types in their retinas, rather than three. These individuals have the potential to perceive 100 times more colors than the rest of us.
Many birds, insects and fish have four types of cones. With their different cones, they can see ultraviolet light. Ultraviolet light has wavelengths shorter than what the human eye can see. Other animals, such as dogs, have fewer types and numbers of cones, so they may see fewer colors than humans do.
Medical Acupuncture and Color Vision
In Oriental Medicine, Color Vision defects basically mean that the meridians have been placed in a stasis condition. That is, it appears that Oriental Medicine has already known about the congeniality of the condition as practitioners see a lack of harmony in the inborn organ to be associated with the disease and consider it treatable once harmony is restored to the organs. Many oriental studies have been conducted regarding treatments for color vision defects using electrical stimulation, and acupuncture.
With the use of acupuncture, several cases have been reported in which color vision defects have been improved.
Until present day, most doctors have not attempted to treat Color Vision defects by medical treatment because they had concluded that the disease is genetic and believed to be impossible to cure.
Oriental medicine approaches disease treatment with the notion that diseases originate mostly from congenital factors, which can be improved by acquired treatment. Having treated people with color vision defects, we certify the effectiveness of our treatment. The key aspect of color vision treatment was acupuncture on targeted spots to activate the retina and optic nerve fibers relevant to eye function.
Treatment for Color Vision correction was used for improving the ability to perceive color by using plates corresponding to patients’ stage of color vision defects. In fact, the researchers underlined the importance of the duration of treatment and the willingness of the patient to be treated.
Color Vision defects cannot be guaranteed to be cured in the shortest period of time as in one of our studies. It would require patients to undergo, at least, 90 to over 120 treatment sessions, and sometimes 180+ times, to recover color vision similar to the normal seeing population.
An important part of treatment is evaluating precisely how the patient perceives his or her own state of color vision. That is, we should first distinguish between the red defect and green defect to decide the level of severity, allowing us to determine the range of perception.
The range of Color Vision defects varies from person to person. As a matter of fact, patients with red and green defects are generally deficient in all of the blue, red, yellow, and green colors. There are individual differences in recovery proceedings after Acupuncture treatment.
We can expect the Acupuncture treatment for Color Vision correction to be effective only when we know the range of color deficiency, as it takes longer to treat red-defect than green-defect. Thus, it is important to distinguish between red and green deficiencies because treatments are applied differently.
Through our Acupuncture treatment, patients often say my vision has brightened or my vision has changed beautifully during treatment. Once, a patient became extremely delighted for suddenly being able to see that his jacket was dark green and not black as he used to think, up to that moment. In conclusion, treatment to correct Color Vision loss is a viable option for those wishing to enjoy a better quality of life.