EnChroma vs ChromaGen: what each lens can and cannot do

Why you are weighing these two

Maybe you watched a video of someone putting on tinted glasses and crying at a sunset. Maybe your child's teacher mentioned dyslexia and someone suggested coloured lenses. Or a work medical has flagged your colour vision and you are hoping a lens will get you through.

Those are three different hopes, and the honest answers differ. This guide puts the two lens systems we fit side by side, using what official bodies and published studies actually found. If you are not yet sure what type of colour vision deficiency you have, start with our guide to what colour blindness is, because the type decides whether either lens is worth trying.

EnChroma: a filter that separates red from green

EnChroma lenses are tinted with minerals that absorb a band of light between red and green. The American Academy of Ophthalmology (AAO) explains that this reduces the overlap between what the red and green cones respond to, so the brain gets a clearer signal to tell the two apart. The AAO adds that the lenses enhance that distinction but do not provide true natural colour vision, that the effect varies widely between people, and that it lasts only while the glasses are on.

Who may notice a difference: the AAO says people with the milder inherited red-green types, deuteranomaly and protanomaly, where the cones are present but not working fully. People whose red or green cones are absent altogether will not see a change, because, as the AAO puts it, glasses cannot replace a missing mechanism. Blue-yellow and complete deficiency are outside what the lens is designed for.

The published tests are sobering. A 2020 study in Optometry and Vision Science (nine colour-deficient adults, five controls) found error scores on a plate test were not clearly improved except in the protan subgroup, that colour naming got worse for some shades, and concluded the results do not support EnChroma filters as a correction for colour discrimination. A 2022 study in Scientific Reports tested 16 colour-deficient adults and eight children on Ishihara, Farnsworth-Munsell 100 hue, colour naming and a sorting task, and found the filters did not significantly compensate in any of them. Some wearers still report colours looking richer or more separate, and that experience is real to them; it is just not the same as scoring better on a clinical test. Our post on how EnChroma glasses work describes the filter in more detail.

ChromaGen: coloured filters for colour deficiency and reading

ChromaGen lenses are coloured filters, fitted as glasses or contact lenses, often with a different tint for each eye. They are sold for two different purposes: helping with colour deficiency, and reducing the distortion of text that some people with dyslexia report, such as words appearing to move or blur.

On reading, the main piece of evidence is a 1999 double-masked, placebo-controlled trial published in the Journal of the American Optometric Association. Forty-seven people with diagnosed dyslexia completed it. Those who reported text distortion read faster with ChromaGen lenses than with placebo lenses, and the gain was strongest in people who were not colour deficient. That is one small trial from one clinic, and it measured reading rate, not spelling, comprehension or school results. A 2022 cohort study of ChromaGen in 156 patients reported improvements, but it had no placebo group, so the result cannot be separated from expectation.

The joint statement of the American Academy of Pediatrics, the AAO, the American Association for Pediatric Ophthalmology and Strabismus and the American Association of Certified Orthoptists is blunt: vision problems are not the cause of dyslexia, the evidence does not support tinted lenses or filters as a treatment for it, and treatment should be structured, individualised literacy instruction. So the fair summary is this: ChromaGen is not a treatment for dyslexia. Some people who see text distort report that a tint makes reading more comfortable, and that is worth testing in the chair with the reading programme continuing regardless. Our post on ChromaGen lenses for dyslexia sets out the fitting process.

On colour deficiency, ChromaGen has not been tested as closely as EnChroma in the studies we could find. The same caution applies: a filter can change how colours look to you, but it cannot add a cone type that is missing.

Neither lens gets you through a work colour test

This is the part people most need to hear before spending money. Occupational standards test colour vision with plates and arrangement tests, under their own lighting, on their own terms. The NZ Police standard screens with the 24-plate Ishihara test and follows up with the Farnsworth D15. The Civil Aviation Authority's colour vision guideline starts with Ishihara and offers lantern, CAD and D15 tests, then a practical flight assessment, for pilots who fail it.

The 2022 Scientific Reports study found no significant Ishihara gain with EnChroma, in adults or children. The AAO also notes that EnChroma, the manufacturer, warns against wearing the lenses while driving, and that because they cut the light reaching the eye they may make night vision worse. Buying either lens to pass a medical is likely to disappoint. What can help is a proper assessment that tells you your type and degree, and the regulator's own list of alternative tests, which for pilots can still lead to a certificate.

• Ask the employer or regulator which tests they use and whether any alternative route exists before you book anything.
• Bring the written report from a colour vision assessment; it shows your type and how marked it is.
• Do not wear tinted lenses to a colour vision test unless the examiner has said in writing that they are permitted.

When this practice is the wrong place

Both lenses are for inherited, stable colour vision deficiency or for reading comfort. A colour change that is new, or different between your two eyes, is not something to fix with a tint. The AAO advises that a significant change in colour perception should be assessed, because it can signal disease of the retina, optic nerve or brain, or a side effect of a medicine. Book an eye examination promptly or see your GP first.

Call 111 or go to the nearest hospital emergency department for sudden loss of vision, a shadow or curtain across your vision, flashes with a sudden shower of floaters, a chemical splash, a red and painful eye with light sensitivity, or an eye injury. For a child who is struggling to read, the first steps are a full eye examination to rule out an uncorrected prescription or focusing problem, and a formal dyslexia assessment through the school; the practice cannot diagnose dyslexia. Light sensitivity and migraine are a different problem again, and our Avulux glasses page covers that, not colour.

How to decide, and what it costs to find out

Start with the colour vision assessment. It identifies the type and degree, which tells our optometrists whether EnChroma is even relevant (mild red-green only) or whether ChromaGen's reading tint is worth trialling. Ask to try the lenses in the clinic, looking at real objects and, if possible, outside in daylight, before you commit. If you see no difference in the chair, you will not see one at home.

Set the expectation honestly: some wearers report brighter or more separate colours, some report nothing, and no one gains normal colour vision. The lens, the frame and any prescription are priced separately; our consultation fees page lists the assessment, and our guide on what affects the cost of eye care and eyewear explains the rest. You are free to walk away with the report and nothing else, and many people do.