ChromaGen lenses are a system of filters that help individuals with dyslexia read. Originally, though, the doctor who created them intended them for people who are color blind. What do color blindness and dyslexia have in common? Apparently, everything, when it comes to finding a corrective aid to help those suffering from these optical conditions.

After dedicating 25 years to perfecting a system of eight filters for patients who are color deficient, Dr. David Harris was surprised to learn that his system also helped dyslexics. When it came time to refine the filters, known as ChromaGen, Harris turned to an optometrist, Dr. Chaaban Zeidan, who further developed the system for dyslexics. Today, ChromaGen is patented, trademarked, and cleared by the Food and Drug Administration for the management of academic skills disorder, an umbrella term that includes color deficiency (another term for color blindness), dyslexia, and related disabilities.

Color Deficiency

The American Academy of Ophthalmology estimates that one in 10 males has some form of color deficiency. Color blindness, as it is more commonly known, is much more typically found in men than women, who seldom have the problem; it is also more likely to affect men of northern European descent. Although three main kinds of color vision defects exist, red-green color vision defects are the most common. Blue-yellow color vision defects are less common, and a severe form, in which everything is seen in shades of gray, is rare. Color blindness is genetic and untreatable, though most people adjust very well and find no limits to their activity.

For people suffering from color blindness, ChromaGen filters work by changing the wavelength of each color going into one or both eyes, and this enhances color perception and color discrimination. In trials of ChromaGen, over 97 percent of color-blind people reported a significant enhancement to their color vision.

Yet, the filter system also helps dyslexics. “Instead of seeing a mass of undecipherable text, I can now see the individual words,” Sonsoles Herras, 40, a dyslexic, reports on the ChromaGen website.


A learning disorder, dyslexia is characterized by difficulties learning to read and occurs in children with normal vision and intelligence. When it comes to reading disorders, some researchers believe that there may be a problem with the large nerve cells that form a path from the eye to the brain. It is thought that these pathways differ in people with reading disorders from those without reading disorders.

After years of studying dyslexia, Harris concluded that the majority of people who have dyslexia see words that that appear to moving on the page in some way. The fitting of ChromaGen lenses helps re-synchronize and selectively change the speed of the information in the pathways to enable sufferers to improve their reading ability. ‘Haploscopic’ refers to any device that presents one image to one eye and another image to the other eye; this is an important part of what the ChromaGen haploscopic filters do — they sift the spectral transmissions in such a manner as to take away the blurring and distortion. For dyslexics, words no longer “jump” on the page.

Only licensed practitioners who have been certified can fit ChromaGen lenses, available as prescription eyeglasses or contacts. FOX News reports that they are not covered by insurance and cost anywhere from $700 to $1,000.

Source: Wilkins AJ, Evans BJW, Allen PM. Coloured Filters -- Do they work? Continuing Education and Training. 2009.