Color vision deficiency, commonly known as color blindness, is a widespread genetic condition that affects the ability to distinguish between certain colors. This condition impacts daily life, making tasks like reading color-coded charts or identifying traffic lights more challenging. Specialized contact lenses designed to improve color perception do exist. These devices offer a technological approach to managing the deficiency, which is most often inherited and has no medical cure.
How Color-Correcting Contact Lenses Work
These specialized contacts act as selective filters, utilizing specific colored dyes or pigments embedded within the lens material, unlike lenses that correct refractive errors. The most common form of the condition involves difficulty distinguishing between red and green hues (protanomaly and deuteranomaly). This difficulty arises because the light signals from the red and green photoreceptor cones in the eye overlap significantly.
The colored tint is designed to absorb or block a specific, narrow band of wavelengths where this confusion occurs, typically in the yellow-green range. By removing this overlapping light, the lens enhances the contrast between the red and green signals that reach the brain. This process is one of contrast enhancement, not a restoration of normal color vision.
These lenses are usually worn in only one eye, leaving the other eye unfiltered. This monocular filtering technique helps the brain compare the two images and further differentiate the colors, aiding in the overall perception of contrast. Different lens types, such as chromatic for red-green deficiencies and anomalous for blue-yellow deficiencies, are tailored to the specific range of light wavelengths causing the individual’s confusion.
Reported Efficacy and Limitations
While color-filtering contacts do not cure the underlying genetic defect, they can significantly improve performance on standardized color vision tests, such as the Ishihara plates. Many users report an improved ability to distinguish between reds, greens, and browns in everyday situations. This enhanced color differentiation can make activities like identifying ripe fruit, selecting clothing, or performing certain professional tasks easier.
The level of effectiveness varies widely and depends on the specific type and severity of the color vision deficiency. Individuals with mild to moderate red-green deficiencies (protanomaly or deuteranomaly) generally experience the best results. Conversely, the lenses are less effective for rarer conditions like blue-yellow deficiency (tritanomaly) and do not restore color perception for total color blindness (achromatopsia). For those with achromatopsia, deep red tints are sometimes used for glare reduction, but not for true color restoration.
The lenses may alter the perception of all colors, not just the problematic ones. Some users may notice a slight reduction in depth perception due to the difference in filtration between the two eyes. Furthermore, using these lenses may not be allowed for certain professions requiring strict color vision standards, such as piloting or law enforcement, as they do not constitute a “cure.”
Acquiring Color Vision Contacts
Obtaining color vision contacts requires a comprehensive eye examination and consultation with an eye care professional, such as an optometrist or ophthalmologist. These lenses are classified as medical devices, even without a vision correction prescription, and cannot be legally purchased without a valid prescription. The initial examination determines the precise type and degree of the deficiency, which is necessary for selecting the appropriate lens tint.
Due to the specialized technology and the need to match the lens to the individual’s specific deficiency, these contacts are often custom-made or require specialized fitting. The process typically involves a trial period where the patient wears trial lenses to assess the level of improvement and comfort. This ensures the chosen lens tint is appropriate for the individual’s needs and lifestyle. The cost for these specialized, custom lenses is significantly higher than standard contacts, often running into several hundred dollars per lens, plus fitting fees.