Treatment of color blindness

Color Blindness Cure

Curing color blindness is currently impossible. 99% of color blind males and females are color blind as a result of defective genetics on the X chromosome. To cure this color blindness would require some form of gene therapy, repairing the damaged chromosome. However even this is only educated circumspection, there is no scientific method available at present that shows any signs of promise of a cure for color blindness.

Color Blindness Correction

Recent developments in light filtering lenses have made it possible to provide color blind people with a greater ability to distinguish between certain shades that otherwise look the same. Many critics claim they are tailored specifically to passing the Ishihara tests for color blindness and have no real world value – you decide on my page about curing and correcting color blindness.

Eye Care

Do you ever spend long periods in the sun, use chemicals (even organic cleaners for the home), use a computer, wear contacts, play sport, or work with flying particles (such as carpentry or welding)? If you answered yes to one of the above and I’m sure most of you did, then I highly recommend you read my page on eye care found in the menu to the left. Educating yourself on the risks you are putting your vision at every day is absolutely essential.

Living with Color Blindness

If you already know you have color blindness, or know someone who does, I recommend you take a look at my page on living with color blindness. Knowing your limitations or those of your color blind family and friends can be of a great benefit in easing the frustrations and reducing the risks and accidental mishaps associated with being color blind. Teachers and parents should pay particular attention. How you handle your child’s color blindness while he is young can have a lasting impact on his/her life, for better or for worse – so I highly recommend educating yourself on color blind life.

For the more than 10 million Americans with colorblindness, there’s never been a treatment, let alone a cure, for the condition that leaves them unable to distinguish certain hues.

Now, for the first time, two University of Washington professors have teamed with a California biotech firm to develop what they say may be a solution: a single shot in the eye that reveals the world in full color.

Jay and Maureen Neitz, husband-and-wife scientists who have studied the vision disorder for years, have arranged an exclusive license agreement between UW and Avalanche Biotechnologies of Menlo Park. Together, they’ve found a new way to deliver genes that can replace missing color-producing proteins in certain cells, called cones, in the eyes.

“I don’t think there’s any question that it will work,” said Maureen Neitz, 57, a UW professor of ophthalmology.

The new treatment — which may be tested in humans within two years — could be a boon for the 1 in 12 men and 1 in 230 women with color-vision deficiency.

The trouble occurs when people are born without one or more of the three types of color-sensing proteins normally present in the cones of the retina. The most common type is red-green colorblindness, followed by blue-yellow colorblindness. A very small proportion of the population is completely colorblind, seeing only shades of gray.

Because they can’t perceive certain colors, they see hues in muted or different shades than people with normal vision.

Brian Chandler, 38, of Seattle, said he first noticed he was colorblind in seventh grade, when he started getting C’s and D’s on drawings in science class.

“I was coloring green stuff brown and brown stuff green,” recalled Chandler, a traffic-safety engineer.

Tulip colors, left, are seen in muted or different shades, right, or only in shades of gray by those who lack one or more crucial proteins in their eyes’ retina cone cells. (LiliGraphie/Neitz Lab)

Colorblindness is often a genetic disorder. It affects mostly men, who can inherit a mutation on the X chromosome that impairs their perception of red and green. A much smaller fraction of cases are in women, who have two X chromosomes, which gives them a better chance of avoiding effects of any genetic defect.

Most people think of colorblindness as an inconvenience or mild disability, mainly causing problems with unmatched shirts and socks. But the Neitzes say the condition can have profound impacts — limiting choices for education or careers, making driving dangerous, and forcing continual adaptation to a world geared for color vision.

“There are an awful lot of people who feel like their life is ruined because they don’t see color,” said Jay Neitz, 61, the professor of ophthalmology who confirmed in 1989 that dogs are colorblind, too.

People may not qualify as commercial pilots, for instance, if they’re colorblind. Other careers that can be limited include those of chefs, decorators, electricians and house painters, all of which require detailed color vision.

The Neitzes have focused on the disorder for years, first proving in 2009 they could use gene therapy to correct colorblindness in male squirrel monkeys, which are born unable to distinguish between red and green.

In the journal Nature, they reported the success of a technique that inserted the human form of a gene that detects red color into a viral shell, and then injected it behind the retinas of two squirrel monkeys.

The monkeys, named Sam and Dalton — the latter after the British chemist John Dalton, who was the first to analyze and report on his own color-vision deficiency — had been trained to recognize colors on a computer screen in exchange for a reward of grape juice. Before the surgery, they couldn’t detect certain hues, while after the procedure they got them right nearly every time.

But that technique is risky, requiring surgery, so the Neitzes were looking for another way to do the job.

“For 10 years, we have been trying to figure out a way to get the genes to go to the back of the eye with a simple shot,” said Neitz.

Now, with the help of Avalanche, the researchers say they’ve developed a technique that does just that. It uses a safe vector, called an adeno-associated virus, to house the pigment gene, which is injected directly into the vitreous, the jellylike center of the eye. Once, there, it targets cells on the back of the retina, said Thomas W. Chalberg Jr., the co-founder and chief executive of the firm.

“It’s a protein shell, kind of like a Trojan horse, that gets you entry into the cell. Once you’re there, the DNA gets to set up shop and produce the photo pigment of interest,” he said. Avalanche has two drug candidates, AVA-322 and AVA-323, that carry pigment-producing genes.

It takes only 30 percent of the cells to be transduced, or changed, to put the world in a whole new hue, Jay Neitz said. Early tests show the technique meets that mark in monkeys.

After preclinical trials are complete, Chalberg said he hopes to move to human trials within one to two years and then seek federal Food and Drug Administration approval for the treatment. Eventually, the treatment could be offered during a single visit to an opthalmologist’s office.

Such a development would be “an amazing advantage,” said Dr. Rohit Varma, a professor of ophthalmology and director of the Eye Institute at the University of Southern California, who is not involved in the research.

“It would cure or at least help people who are colorblind,” he said. “This is the first hope, in many ways, for these individuals that suffer from this.”

While noting that many tests which succeeded in animals have later failed in humans, he said he’s cautiously optimistic the trials will deliver as promised. Plus, he said, it will be important to learn whether the therapy not only adds the color-sensing ability, but actually improves the lives of those who are treated.

That’s a thought echoed by Dr. Paul Sternberg Jr., chairman of the Vanderbilt Eye Institute at Vanderbilt University in Nashville and a clinical spokesman for the American Academy of Ophthalmology. He called the Neitzes “world-class scientists” and said the wider field awaits potential human trials of the technique.

“The brain develops a certain way of seeing,” he said. “We don’t know whether replacing the visual pigment in a 25-year-old colorblind man will allow him to see in full color.”

Already there appears to be high interest in finding out. Since March 25, more than 10,000 people have visited a new website associated with the project, www.colorvisionawareness.com, including many who hope to be the first cured of the condition.

“I definitely would be interested,” said David Curry, 33, of Port Townsend, who had to abandon a dream of becoming a commercial helicopter pilot because of his deuteranopia, or red-green colorblindness. “I’d want to speak to Professor Neitz more and learn about the process more before putting my eyes on the chopping block, so to speak. But I’ve always wondered what it would look like to see color like everyone else.”

Brian Chandler, also colorblind, isn’t so sure. He said he’s learned to adapt to the world using cues other than color to get along.

“I have mixed feelings about ‘curing’ my color-vision deficiency,” said Chandler. “On one hand, I’m nervous about the change, since I’ve seen like this my entire life. On the other, it would potentially be exciting to see things I had not seen before.”

For their part, the Neitzes say they’re eager to see a lifetime of work put into clinical practice. The technique to correct colorblindness also might eventually be used for other cone-based disorders, including retinitis pigmentosa, an inherited disorder that can lead to blindness.

Curing colorblindness, though, could affect millions who would like to know what they’re missing, the scientists said.

“There’s nobody with a black-and-white TV who, if you said, ‘Would you like color TV?’ wouldn’t trade it,” Jay Neitz said.

Color Blindness Treatment

While certain treatments help some people better perceive colors, it’s important to find ways of adapting to color blindness.

Color blindness is a type of color vision deficiency that makes it difficult to see certain colors, or perceive obvious differences between two colors under normal lighting.

Most forms of color blindness are inherited at birth.

The most common form of color blindness is red-green color blindness. People with this condition have a hard time distinguishing between different shades of reds and greens.

There’s no cure for color blindness, and no medical treatments currently exist for inherited forms of color blindness.

Most people with color blindness learn to adapt and live with the condition. For many people, a color vision deficiency is a relatively minor inconvenience.

Some people go many years without even knowing that they see colors differently from how most people see them.

They’re diagnosed with color blindness as an adult, or they may never receive a diagnosis of color blindness.

Living With Color Blindness

Here are some ways to work around poor color vision:

  • Memorize the order of colored objects, such as traffic lights.
  • Have someone with good color vision label and sort your clothing or other items that you want to match.
  • Use a smartphone or tablet app designed for people with poor color vision (which allows users to detect colors of objects).

If your child has color blindness, let teachers know that your child has trouble seeing certain colors.

Children with color blindness may have a hard time seeing yellow chalk on a green chalkboard, or reading assignments printed on colored paper or with colored ink.

Teach your child the colors of common items. This can provide a frame of reference for when other people are discussing colors in your child’s presence.

Color Blindness Glasses

People with certain forms of red-green color blindness may be able to use a special set of glasses (or contact lenses) to help them perceive colors more accurately under certain lighting conditions.

These glasses work by filtering out certain wavelengths of light to help people better distinguish red and green colors. They don’t restore normal color vision, but they may make certain hues appear more vibrant.

Color-corrective glasses don’t work for everyone with red-green color blindness. Your eye doctor can help you determine whether you might benefit from these glasses.

Treatments for Achromatopsia

People with a severe form of color blindness called achromatopsia cannot see any colors.

Red-colored lenses can help reduce sensitivity to light for people with achromatopsia.

A device called an eyeborg can help people with achromatopsia perceive color through sound waves.

Color Blindness Research

Researchers are working on new ways to treat color blindness.

Some research has focused on gene therapies to correct the genetic abnormalities that cause the most common forms of color blindness.

Potential gene replacement therapy for red-green color blindness has already been tested in animals.

Last year, researchers in Seattle announced that they were developing a gene-based therapy for red-green color blindness in humans, but a cure for red-green color blindness is likely still several years away.

PMC

Gene therapy was performed on adult squirrel monkeys (Saimiri sciureus) that were missing the L opsin gene. In this species, some females have trichromatic colour vision while males are red-green colour blind2. Serotype 2/5 recombinant adeno-associated virus (rAAV) containing a human L-opsin gene under control of the L/M opsin enhancer and promoter (Fig. 1a) was delivered to the photoreceptor layer via subretinal injections (see Full Methods online). Transcriptional regulatory elements were chosen to direct expression preferentially in M cones, but not short- (S) wavelength-sensitive cones or rods 3. To provide the receptoral basis for trichromacy, animals received three 100 μL injections (containing a total of 2.7×1013 viral particles) in each eye which produced a relatively uniform, third submosaic of approximately 15–36% of M cones that coexpressed the transgene (Fig. 1e, f).

rAAV2/5 vector produced functional L-opsin in primate retina. a, Molecular map; TR = terminal repeats; LCR = locus control region; PP = proximal promoter; SD/SA = splice donor/acceptor; RHLOPS = recombinant human L opsin cDNA; PA1 = polyadenylation signal. b, Red light mf-ERG stimulus. c, Mf-ERG 40 weeks after two injections (yellow circles) of a mixture of L-opsin- and GFP-coding viruses. Grey lines show borders of highest response; for comparison, inset = mfERG 16 weeks post-injection; there was no reliable signal from L-opsin, unchanged from baseline. High responses in far peripheral retina were measured reliably and may have originated from offshoot of one of the injections. d, Fluorescence photographs from a similar retinal area as c; grey lines from c were copied in d. e, Confocal microscopy revealed a mosaic pattern of GFP expression in 5–12% of cones. Because GFP-coding virus was diluted to 1/3 compared to L-opsin virus, an estimated 15–36% of cones in behaviourally tested animals express L-opsin. f, Mf-ERG from a behaviourally tested animal 70 weeks after 3 injections of L-opsin virus.

Prior to treatment, monkeys were trained to perform a computer-based colour vision test, the Cambridge Colour Test4,5, which was modified for use with animals6 (Fig. 2a). Dichromats who are missing either the L- or M-photopigment fail to distinguish from grey: colours near the so-called “spectral neutral point” located in the blue-green region of colour space (near dominant wavelength (DW) 490 nm) and complementary colours near the “extra-spectral neutral point,” in the red-violet region (near DW = −499 nm). While trichromats have four main hue percepts – blue, yellow, red, and green – dichromats have only two percepts, nominally blue and yellow. Before treatment, two dichromatic monkeys completed three colour vision tests consisting of 16 hues (Fig. 2b, c). Four-to-six months was required to test all 16 hues; thus, baseline results represent testing conducted for more than a year. As predicted, prior to treatment monkeys had low thresholds (averaging < 0.03 units in u’, v’ colour space) for colours that represent blues and yellows to their eyes, but always failed to discriminate the blue-green (DW = 490 nm) and red-violet hues (DW = −499 nm) with thresholds extrapolated from psychometric functions being orders of magnitude higher (Fig. 2b, c). Results were highly repeatable, with no improvement between the first and third tests, making us confident that animals would not spontaneously improve in the absence of treatment.

Pre-therapy colour vision and possible treatment outcomes. a, Colour vision stimuli examples. b, Pre-therapy results, monkey 1. Hues tested are represented as dominant wavelengths (DWs) rather than u’, v’ coordinates. If a hue could not be reliably distinguished at even the highest saturation, the extrapolated threshold approached infinity. c, Pre-therapy results, monkey 2. de, Possible experimental outcomes: Monkeys could have a relative increase in long-wavelength sensitivity, but remain dichromatic (dashed lines, d); theoretical colour spectrum appearances for a dichromat and a possible “spectral shift” are shown. Alternatively, dichromatic monkeys could become trichromatic. Results from a trichromatic female control monkey are plotted (dashed line, e; error bars = SEM and n varied from 7–11).

Co-expressing the L-opsin transgene within a subset of endogenous M-cones shifted their spectral sensitivity to respond to long wavelength light, thus producing two distinct cone types absorbing in the middle-to-long wavelengths, as required for trichromacy. The spectral sensitivity shift was readily detected using a custom-built wide-field colour multifocal electroretinogram (mf-ERG) system (Fig. 1b, c, f) (see ref. 7 for details). In preliminary experiments, validity of the colour mf-ERG was tested using an animal that had received a mixture of the L-opsin-coding virus plus an identical virus, except that a green fluorescent protein (GFP) gene replaced the L-opsin gene. As reported previously, faint GFP fluorescence was first detected at 9 weeks post-injection, and it continued to increase in area and intensity through 24 weeks8. While faint signs of GFP were first detectable at 9 weeks, L-opsin levels sufficient to produce suprathreshold mf-ERG signals were still not present at 16 weeks post-injection (Fig. 1c, inset). After GFP fluorescence became robust, the red light mf-ERG, which indicates responses from the introduced L-opsin, showed highly elevated response amplitudes in two areas (Fig. 1c) corresponding to locations of subretinal injections (Fig. 1d).

The two dichromatic monkeys who participated in behavioural tests of colour vision were treated with only L-opsin-coding virus. While the elongated pattern produced by two injections in Fig. 1c and d allowed mf-ERG validation, the treatment goal was to produce a homogeneous region, as resulted from 3 injections shown in f, where the highest mf-ERG response covered about 80° of central retina, roughly the area for which humans have good red-green discrimination. These results demonstrate that gene therapy changed the spectral sensitivity of a subset of the cones. A priori, there were two possibilities for how a change in spectral sensitivity might change colour vision behaviour: 1) animals may have an increase in sensitivity to long-wavelength light, but if the neural circuitry for extracting colour information from the nascent “M+L cone” submosaic was absent, they would remain dichromatic, the hallmark of which is having two hues that are indistinguishable from grey (Fig. 2d). The spectral neutral point for individuals that have only S- and M-cones, (e.g. monkeys 1 and 2 pre-therapy), occurs near dominant wavelength (DW) = 495 nm. At the limit, an increase in spectral sensitivity would shift the monkeys’ neutral point toward that of individuals with only S and L cones, near DW = 505 nm (dashed blue lines, Fig. 2d). 2) The second, more engaging possibility was that treatment would be sufficient to expand sensory capacity in monkeys, providing them with trichromatic vision. In this case, the animals’ post-therapy results would appear similar to Fig. 2e, obtained from a trichromatic female control monkey.

Daily testing continued after treatment. After about 20 weeks post-injection (arrow, Fig. 3a), the trained monkeys’ thresholds for blue-green and red-violet (DWs = 490 and −499nm, respectively, Fig. 3b, c) improved, reducing to an average of 0.08 units in u’, v’ colour space, indicating that they gained trichromatic vision. This time point corresponded to the same period in which robust levels of transgene expression were reported in the squirrel monkey8. A trichromatic female monkey and untreated dichromatic monkeys were tested in parallel. As expected, the female had low thresholds for all colours, averaging < 0.03 units in u’, v’ colour space, but the untreated dichromats always failed to discriminate DWs = 490 nm (triangle, Fig. 3a) and −499 nm, indicating a clear difference between treated and untreated monkeys.

Gene therapy produced trichromatic colour vision. a, Time course of thresholds for the blue-green confusion colour, DW = 490 nm (circles), and a yellowish colour, DW = 554 nm (squares). A logarithmic scale was used to fit high thresholds for DW = 490 nm; significant improvement occurred after 20 weeks. Enclosed data points = untreated dichromatic monkey thresholds, DW = 490 nm (triangle) and DW = 554 nm (diamond). b–c, Comparison of pre-therapy (open circles, solid line) and post-therapy thresholds (solid dots, dashed line). Enclosed data points are DW = 490 nm thresholds when tested against a red-violet background (DW = −499 nm); pink triangles = trichromatic female control thresholds. Error bars = SEM; n varied from 7–11.

Early experiments in which we obtained negative results served as “sham controls,” demonstrating that acquiring a new dimension of colour vision requires a shift in spectral sensitivity that results from expression of an L pigment in a subset of M cones. Using similar subretinal injection procedures, we delivered fewer viral particles of an L-opsin-coding rAAV2/5 virus with an extra 146 base pair (bp) segment near the splice donor/acceptor site that had been carried over from the cloning vector and that was absent in the GFP-coding rAAV2/5 virus. The 146 bp segment contained an ATG and a duplicate mRNA start site that may have interfered with expression (see Full Methods online). Three monkeys received injections of this vector, containing an average of 1.7×1012 virus particles per eye, and no reliable changes in spectral sensitivity were measured using the ERG. One animal was also tested behaviourally and his colour vision was unchanged from baseline 1 year after injection. In subsequent experiments reported here, we removed the extra 146 bp segment and also increased the amount of viral particles delivered per eye by approximately 16-fold, to 2.7×1013. Negative results from earlier injections demonstrated that the subretinal injection procedure itself does not produce changes in the ERG or in colour vision.

The change in spectral sensitivity measured with the mf-ERG is necessary but not sufficient to produce a new colour vision capacity. For example, individuals with L but no M cones (termed deuteranopes) have a relatively enhanced sensitivity to red light but they are still as dichromatic as individuals with M but no L cones (protanopes), in that they are unable to distinguish particular “colours” from grey. To verify that the behavioural change observed in animals expressing the L pigment transgene was not purely a shift in spectral sensitivity (see Fig. 2d), monkey 1 was also tested on DWs = 496 and 500 nm, and monkey 2 was tested on DWs 496 and 507 nm. Together, these DWs span the possible confusion points for deuteranopes and protanopes and for any intermediate dichromatic forms that could arise from expressing combinations of L and M pigments. As shown in Fig. 3b and c, both monkeys’ measured thresholds for these additional hues were similar to their thresholds for DW = 490 nm, demonstrating they now lacked a spectral neutral point and have become truly trichromatic. Furthermore, treated monkeys were able to discriminate blue-green (DW = 490 nm) when it was tested against a red-violet background (DW = −499 nm), instead of the grey background, indicating that the monkeys’ newly-acquired “green” and “red” percepts were distinct from one another. The treated monkeys’ improvement in colour vision has remained stable for over 2 years and we plan to continue testing the animals to evaluate long term treatment effects.

Classic experiments in which visual deprivation of one eye during development caused permanent vision loss1 led to the idea that inputs must be present during development for the formation of circuits to process them. From the clear change in behaviour associated with treatment, compared both between and within subjects, we conclude that adult monkeys gained new colour vision capacities because of gene therapy. These startling empirical results provide insight into the evolutionary question of what changes in the visual system are required for adding a new dimension of colour vision. Previously, it seemed possible that a transformation from dichromacy to trichromacy would require evolutionary/developmental changes, in addition to acquiring a third cone type. For example, L and M opsin-specific genetic regulatory elements might have been required to direct the opsins into distinct cone types9 that would be recognized by L and M cone-specific retinal circuitry10, and to account for cortical processing, multi-stage circuitry11 might have evolved specifically for the purpose of trichromacy. However, our results demonstrate that trichromatic colour vision behaviour requires nothing more than a third cone type. As an alternative to the idea that the new dimension of colour vision arose by acquisition of a new L vs. M pathway, it is possible that it exploited the pre-existing blue-yellow circuitry. For example, if addition of the third cone class split the formerly S vs. M receptive fields into two types with differing spectral sensitivities, this would obviate the need for neural rewiring as part of the process of adopting new colour vision.

Some form of inherent plasticity in the mammalian visual system can be inferred from the acquisition of novel colour vision, as was also demonstrated in genetically engineered mice12; however, the point has been made that such plasticity need not imply that any rewiring of the neural circuitry has occurred 13. Similarly, given the fact that new colour vision behaviour in adult squirrel monkeys corresponded to the same time interval as the appearance of robust levels of transgene expression, we conclude that rewiring of the visual system was not associated with the change from dichromatic to trichromatic vision.

Treated adult monkeys unquestionably respond to colours previously invisible to them. The internal experiences associated with the dramatic change in discrimination thresholds measured here cannot be determined; therefore, we cannot know whether the animals experience new internal sensations of “red” and “green.” Nonetheless, we do know that evolution acts on behaviour, not on internalized experiences, and we suggest that gene therapy recapitulated what occurred during evolution of trichromacy in primates. These experiments demonstrate that a new colour vision capacity, as defined by new discrimination abilities, can be added by taking advantage of pre-existing neural circuitry and, internal experience aside, full colour vision could have evolved in the absence of any other change in the visual system except the addition of a third cone type.

Gene therapy trials are underway for Leber’s congenital amaurosis14–16. Thus far, treatment has been administered to individuals who have suffered retinal degeneration from the disease. The experiments reported here are the first to use gene therapy in primates to address a vision disorder in which all photoreceptors are intact and healthy, making it possible to assess the full potential of gene therapy to restore visual capacities. Treatment allowing monkeys to see new colours in adulthood provides a striking counter-example to what occurs under conditions of monocular deprivation. For instance, it is impossible to restore vision in an adult who had grown up with a unilateral cataract. Future technologies will allow many opportunities for functions to be added or restored in the eye. While some changes may produce outcomes analogous to monocular deprivation, we predict that others, like gene therapy for red-green colour blindness, will provide vision where there was previously blindness.

If you first learn about your or one of your kids color vision deficiency there is one thing which comes to your mind often just after you learned what it really means to you: Is there a cure for color blindness?

The short answer to this questions is simply: No. And the long answer: There is no cure for color blindness—yet. There are some scientific studies going on which had just recently quite a big breakthrough. This and some other interesting ideas about aids for colorblind people are the topic of this article of the Color Blind Essentials series.

First ideas

“No method had been found for the correction of color blindness any treatment which convinces operators that they can see colors they could not see before will decrease safety in transportation, decrease security in national defense, and decrease efficiency in industry.”
– American Committee on Optics & Visual Physiology

As with many other handicaps or diseases when some people learned that some others can’t really distinguish colors like themselves, laziness was the first thing which came to their mind. Because of that many colorblind people just started to learn color names more intensively—without any success.

There were also some other techniques like warming one eye, electrical stimulation, injections of iodine or extracts of cobra venom, vitamins or flashing light. All this finally resulted in an official statement of different Academies and Medical Associations that no method had been found for the correction of color blindness, whether called ‘color weakness’, ‘color confusion’ or ‘color defectiveness’—which is still true as of today.

But there were also some good ideas around like color filters or spectacles with horizontally divided red and green sections.

Aids for colorblind people

If you have a closer look at the available tools for color deficient people, you have on one side the computer and all its possibilities and on the other side non-computer based aids.

On the non-computer side there is actually just one technique used: colored filters. These filters come in different forms:

  • Lenses: Manufacturers of tinted lenses claim that their product can improve color vision for colorblind users. And people often read this as if they could almost cure your color blindness—which is wrong. Here are some facts about tinted lenses:
    • They have to be worn in only one eye, as otherwise fewer colors are seen.
    • It needs some time to get used to them and learn some new colors.
    • They can help you and enhance your color perception in certain situations.
    • You want be able to see more colors, but maybe other ones then you are used to.
    • Certain colors seem to vibrate or shimmer because of the usage in only one eye.
    • Worn while you are driving they can be a safety risk because of the worse perception at dim light situations.
  • Glasses: It is almost the same for colored glasses as for lenses. The first products looked a bit strange as only one glass is tinted. Recent products have some coating which reduces this effect and makes glasses a true alternative for the lenses.
  • Tools: There is a little tool called Seekey which is made of two tinted filters, one in green and the other in red. If you look through the filters on and off you can definitely distinguish more colors as a colorblind. This can be an advantage for some specific tasks in certain professions or in some everyday life situations. Such filters can also enhance certain diagnostic or medical instruments and help the colorblind operators to see what they otherwise wouldn’t spot that easy.

Many colored filters can help you to pass some color blindness tests, specially the famous Ishihara plates test. But this is not the correct purpose as those tests are usually there to assure, that your color vision isn’t a safety issue. Because of that in most cases tinted filters are not allowed to be used on such qualifying tests.

If we have a look at the computer based helpers for colorblind users, there are different tools available. Those tools make use of different techniques which can only be done digitally.

  • Show the name of a color if you point to it.
  • Shift the whole color spectrum around the color wheel.
  • Highlight certain specific colors in a different color.
  • Use a pattern to highlight certain tints.
  • Some sophisticated algorithms which try to manipulate a picture to the effect that colorblind people perceive it still as normal but that certain shades can be distinguished better.

Such tools might really help you in some specific situations. But often they are not that easy to adapt for your personal purposes and sometimes just to cumbersome to handle. And don’t forget that all those tools can only be used while working on a computer, which is in everyday life often not such a big handicap for colorblind people.

Cure of color vision deficiency

As mentioned in the lead of this article there is to this day no cure for colorblind people available—but it looks like as if there is one for colorblind monkeys!

Monkey Performing Color Blindness Test

Jay Neitz, a well known vision scientist, and his team developed a gene therapy to enhance color vision. Colorblind monkeys were used as test animals. They received the gene injections directly into their eyes to build up the missing color receptor.

The monkeys had to perform a color blindness test and if they did well they received a reward. After a while they started to perform much better on a task they couldn’t accomplish before because of their vision handicap.

Due to this test result many colorblind people hope to be able to get rid of their color vision deficiency in the near future. Unfortunately this won’t come true that fast. And there are some difficulties which have to be overcome until this dream could get true:

  • Gene therapy for red-green color blindness may not work for humans as well as it does for monkeys.
  • Side effects of subretinal injections can include irritation or infection, in addition to the risks of permanent retinal detachment and blindness at the injection site.
  • There could be adverse psychological effects associated with suddenly being able to see new colors and learning how to categorize them.

Also other institutions started to pick up this topic and are looking into the development of such a gene therapy to heal congenital color vision deficiency.

There is a possibility that a color vision handicap can disappear again. In some cases of acquired color blindness, specially for vision deficiencies which can occur after a hard hit on your head, it is reported that this handicap can disappear again after a certain time. Unfortunately this can’t be influenced and the process of healing can’t be used for all other colorblind people.

This was the last part of the Color Blind Essentials series. If you would like to learn more details about color vision deficiency why don’t you browse my articles archive, try some of the color blindness tests or check out my tools including a color blindness simulator.

How To Cure Color Blindness Naturally?

There are so many ocular diseases that we come across nowadays. We are pretty sure that you have people in your circle who have vision problems, most commonly nearsightedness and farsightedness and they use glasses or contact lenses to correct their vision.

However, you might not know about it but there are high chances that you do have a colorblind person too in your circle.

Among all the other vision problems, color blindness is something that is very less problematic and if your condition is not that severe then there is nothing to worry about.

However, it is a proven fact that color blindness comes with negative impacts when it comes to education, career and in some places in the world, color blind people are not even allowed to drive cars as sometimes they are unable to see the red and yellow signal.

It’s just that if you have a severe vision color deficiency problem then you’ve got to do something about it.

What’s The Cure?

Now, many of you might be wondering that what exactly can you do if you are color blind because this is something that is inherited and a person has no control over it.

Well, to be honest, there isn’t anything you can actually do about color blindness, sadly, you just have to live with it.

A gene therapy experiment was done on monkeys who were color blind and it was successful but scientists are still trying hard to experiment this therapy on humans, they are just afraid that the gene therapy can have some negative effects on the human brain, so nothing yet can be said about it at the moment.

It is said that color blindness is found more in men than women because men have only one X chromosome and they are prone to color deficiency because it’s easy for them to acquire it.

There are some other rare cases in which a person can acquire color blindness, for example if you know someone who is suffering through long-standing diseases such as multiple sclerosis or diabetes then yes, they do have high chances to fall victim to this disease.

The most common types of color blindness are the ones in which a person is unable to differentiate between yellow and blue and the other type is the one in which people confuse red for green.

Another shocking thing about color blindness is that more than half of the colorblind people don’t even know that they have this disease until they reach their adulthood.

So, if you are someone who wants to get your vision checked for this disease then you can take your test here https://iristech.co/test-vision/ .

If you just got diagnosed of color blindness then don’t worry because we do have something that can improve your condition and here we are talking about the Vision software.

What’s The Vision Software?

This software is unlike anything you have seen before. The sole purpose of vision is to improve the color blindness of the patients through different online treatments.

This software has helped more than a thousand people in improving their condition.

Vision does not claim to be the cure to your disease but the only thing is that it helps people in differentiating between different colors and shades easily.

The regular use of this software can actually be very beneficial for you and your eyes.

So, if you know someone who is color blind or if you are the one who needs some treatment then you’ve got to try this software for once and we assure you that you’ll see the positive results for yourself.

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Is color blindness
an obstacle for your career?

ColorCorrection System ™ – A Proven Treatment for Color Blindness
Are you ready to see brilliant color? The ColorCorrection System uses unique tests and filters to create customized ColorCorrect Lenses, designed to match the exact wavelength of light for an individual’s color vision correction need. With the ColorCorrection System ™, people with color vision problems, like color blindness, can see the full range of colors again. Whether you are struggling to get work because of your condition or simply wish to see brilliant colors, the ColorCorrection System ™ is the solution.

Pass Work-Required Color Blindness Tests
With the ColorCorrection System ™, you now have the freedom to choose a career you love, without the fear of passing a color vision test. Employers can now hire the best candidates with a proven solution for colorblindness. With these corrective glasses or contact lenses, candidates can pass the Ishihara Color Plate Test, allowing them to work in fulfilling careers.

Enjoy a Better Quality of Life
Red-Green color blindness and other color vision concerns significantly impact an individual’s life, impacting everything from deciphering traffic lights to choosing clothing in the morning. With the ColorCorrection System, those with inherited color blindness or color blindness due to medications, eye disease, or trauma now have a working solution to treat the problem.

If you suspect that you struggle with color blindness, take the color-blind test today, then learn more about the ColorCorrection System and how it can improve your life for the better.

Gene Therapy

How was gene therapy for red-green color blindness able to work in adult monkeys?

Because the new dimension of red-green color vision was closely timed with the appearance of expression of the new visual pigment transgene, we conclude that neural rewiring was not associated with the change in color vision. Rather, the new visual pigment took advantage of pre-existing visual circuitry and altered its spectral response characteristics to automatically give rise to a new dimension of color.

What is the neural circuitry for color vision? Hundreds of years of color vision and color matching experiments have established that the four main hue percepts (blue, yellow, red, and green) involve contributions from all three cone types, short- (S), middle- (M), and long- (L) wavelength-sensitive. Theories of color vision have focused on cell types recorded physiologically in the retina and LGN with S vs. (L+M) and L vs. M signatures. As a result, textbooks have attributed blue-yellow and red-green perceptions to the respective cells containing these signals. Importantly it must be emphasized the physiology of these cell types do not match the spectral characteristics of human perception. It is possible hue perception is based on cells in the retina matching the spectral signatures of human color vision.

In understanding color vision it helps to first consider reduced systems with fewer cone types and fewer percepts. In dichromatic animals, retinas are composed of either S- and M-cones (protanope) or S- and L-cones (deuteranope) as shown in the figure below. When behaviorally tested these animals demonstrate the ability to discriminate blues and yellows, whereas greens and reds are indistinguishable from gray.

protanope

deuteranope

The relative percentage of S-cones when compared to the total number of cones retina remains similar across mammals, at around 5-7% of the whole. This creates a unique sampling mosaic that is conserved across many species, in which chromatic information is available only from the M vs. S (or L vs. S) receptive fields. For example, the dichromatic squirrel monkeys only had M and S cones. Their M vs. M center-surround receptive fields carry only light-dark edge information. Therefore, color signals leaving the dichromatic retina are carried down two pathways, those with S-cone centers and those with M cone centers with S-cone inputs to the surround.

In the gene therapy experiment the pre-treated retinas contained only S- and M-cones. By adding a third class of cone the existing M center vs. S surround circuitry was split into two pathways; an M vs. (S+L) and an L vs. (S+M) thus creating new, uncorrelated, activity patterns leaving the retina. Receptive fields that do not have S cone inputs do not contribute to hue perception in dichromats. If the cells in trichromats without S cone input do not contribute to hue perception, then it is not necessary to propose that an entire visual pathway that was previously dedicated to spatial vision was converted to a new purpose of color vision. Gaining a new dimension of color vision becomes a simple matter of splitting the preexisting blue-yellow pathway into two systems, one for blue-yellow and a second for red-green color vision.

untreated protanope

trichromatic as a result of gene therapy

By applying these basic rules, we have constructed a flash based circuit demonstration which can be found here. Please follow the link and play around with the circuit. Instructions are on the left to perform a virtual version of the gene therapy project. Also available is a pdf of the circuits described here. Click on the picture below to begin downloading.

A Cure for Colorblindness?

This transcript has been automatically generated and may not be 100% accurate.

… I … in a … few … color blindness on the twenty oh some scientists to excuse me this there’s also a lot of new developments in terms of treatments Melinda Beck joined us right now she’s one hell calmness appreciate you being with us we also … had Dr Jane nineties on the ponies of the age and scientists at the University of Washington thanks so much to both of you now … when that list is for and didn’t have the scope of this column blindness … on how prevalent is the problem very very prevalent nine eight percent of men and about a half percent of women and had some degree of color blindness … and … can affect their daily life in its building what ways are those of us who don’t have it coming … right that’s right it’s what you think that … if you don’t have it and it can be very severe very mild in everything in between any two main effects people … in their career choice and lots of three-year center really on limits because they require … very precise color recognition … and I mean bring you here for second describe the people who have … color blindness scene when we think were seen or read or we think we’re seeing green when they see … Obama was the most common forms of color blindness … that … but so many people recall the red green color blindness … and for those people that are completely wrecking color blind … they don’t have the sensation of red … or green … and so when they see is … something that the shire ad agency Grey … and pure greed based Aegis threat … so where’s the computers those things … but they don’t see … the red and purple … sell because purple is coming true blue and red … so … for all slept well into the … shoes and they don’t even with an orange oranges look yell into that … and all the difference of all shapes colors that have both read this previous … posting just missing all those colors are missing … and to stand in your new and working I know I care for them to come back to bed to second among Iowa me asking this … on the secured debt could be coming … to the law or systems out there and things like glasses and apps walk us through some of what people can can go to … yes the rest the world is really breaking up to the fact that that … this affects a lot of people and then there are … dozens of websites that can help … you see what color blind people would see and help you evaluate your business marketing materials for example of how he would just your chart so that everybody and then can see them … and her son apps and … it can even … what color blind people see what … kind of colors and use it … on … even in real time … looking through the cameras year I found this on camera … amazing and honestly what everybody would hope for is that to secure altogether and Akamai t think it’s an interesting … experience with squirrel monkeys can you very … briefly tells about what you found in your work there … well we’ve been able to share it to look like this in monkeys and the squirrel monkeys … aam and their other boy this is exactly like humans … and what we view this as gene therapy that I’d I think she missed me saying that the cause of the blinds … and and and and that and you’ve seen success with that you know how long to be before that can be taken … by and test IQ nose … well … with … the trio trust humans we have picked up two things that were sure of … that … given that it’s a … and … her … excitement when she showed that its super but it … but you know now we have to work are always things to make sure that there’s … no … there’s no possibility that the … that revived without any … adverse effects in humans of actually working on now … and just didn’t handle and that some people don’t even know their color blind … until later in life is the correct they just asked What how they find out just us continued on and that’s not that color twelve having some people find out we may take a vision test for John and … train for hope or other lines … on some people decided never get that test done and and I down there on … that there is I’m a lot of movement to have kids tested for … a … new color blindness very early on because a lot of early learning for … kids and learned their numbers and letters … rely on recognizing colors and I and kids have been labeled learning Despite disable it sound like they can follow instructions many just can’t see that went to import to find out as early as possible I’m going to back think semester being

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