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Heterochromia: Different Coloured Eyes, Causes, Types and When to Worry
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Heterochromia (noun; also heterochromia iridis, from the Greek for "different colour"): heterochromia is a difference in iris colour. It can mean one iris is a different colour from the other (for example one blue eye and one brown eye), part of one iris differs in colour, or an inner ring differs from the outer iris. It may be present from birth and harmless, or it may appear later in life as a sign of injury, inflammation, medication effect or another eye or body condition, which is why a new colour difference should always be examined by an ophthalmologist.
In short: an eye colour difference that has been there since birth, with no other symptoms, is usually a harmless variation. A colour difference that is new, changing or accompanied by pain, redness, blurred vision or a drooping eyelid needs a prompt eye examination. At Laser Istanbul Clinic, Doç. Dr. Muhammet Derda Özer (Doç. is the Turkish title for Associate Professor; uveitis, ocular oncology and cataract) and Prof. Dr. Ahmet Satıcı (glaucoma and cataract) examine and treat the eye conditions that can sit behind acquired heterochromia.
Heterochromia: key facts
- What it is
- A difference in the colour of the iris (the coloured part of the eye), between the two eyes or within one eye
- Three patterns
- Complete (one iris entirely different from the other), sectoral or partial (part of one iris), central (an inner ring differs from the outer iris)
- Present from birth?
- Often, as a benign variation or from a genetic or developmental condition; it can also be acquired later
- What decides iris colour
- The amount and distribution of melanin pigment in the iris
- Usually harmless?
- Often when present from birth and isolated; not when new, changing or accompanied by other signs
- Does it affect sight?
- Not by itself. Any vision problem comes from an underlying cause, not from the colour difference
- Treatment
- Treat the cause if there is one; if it is isolated, no treatment may be needed
- Specialist
- Ophthalmologist; at Laser Istanbul Clinic, Doç. Dr. Muhammet Derda Özer for uveitis and ocular tumours, Prof. Dr. Ahmet Satıcı for glaucoma
What are the types of heterochromia?
The American Academy of Ophthalmology (AAO) describes three patterns. Which pattern you have is a description of how the eyes look; it does not by itself say whether the cause is harmless.
| Type | What you see | Example |
|---|---|---|
| Complete heterochromia | One iris is entirely a different colour from the other | One brown eye and one blue eye |
| Sectoral (partial) heterochromia | Part of one iris is a different colour from the rest of that same iris | A brown wedge or patch in a blue iris |
| Central heterochromia | An inner ring around the pupil differs from the outer part of the iris | A golden-brown ring around the pupil in a green or blue eye |
Doctors also describe the affected iris as hyperchromic (darker than expected) or hypochromic (paler than expected), because that can help point to the cause. Some textbooks reserve heterochromia iridum for a difference between the two eyes and heterochromia iridis for a difference within one iris; most patient sources use the terms interchangeably.
Heterochromia is also described by when it starts. Congenital heterochromia is present at birth or appears in early childhood. Acquired heterochromia develops later, after an injury, disease or medication.
What causes heterochromia?
Iris colour depends mainly on how much melanin pigment there is in the iris and how it is spread. Anything that changes the number of pigment cells, the pigment they make or the pigment deposited in the iris can produce a colour difference.
Congenital (from birth) causes
AAO states that babies can be born with heterochromia either as a benign variation or because of an underlying condition. Congenital heterochromia can be inherited: a case report in the Journal of Ophthalmic and Vision Research describes a family in which sectoral heterochromia passed through three generations in an autosomal dominant pattern. Genetic mosaicism and chimerism (cells with different genetic make-up within the same person) have also been described as causes.
Conditions that can come with congenital heterochromia include:
- Waardenburg syndrome. A genetic condition that affects pigment. According to MedlinePlus Genetics it affects an estimated 1 in 40,000 people. Typical features are very pale blue eyes or eyes of different colours, sometimes two colours within one iris, a patch of white hair or hair that turns grey early, and, in some people, hearing loss present from birth. Most people with the syndrome have normal hearing. Type IV is combined with Hirschsprung disease, an intestinal disorder.
- Congenital Horner syndrome. When the sympathetic nerve supply to one eye is reduced, the iris of that eye can develop less pigment, so it stays paler, particularly when the nerve problem starts in the first two years of life (Deprez et al., 2015). Horner syndrome also causes a smaller pupil and a slightly drooping upper eyelid on the same side (see our guide to ptosis). Doctors investigate the cause, and in the case report cited here, skull-base CT showed an underdeveloped carotid artery on the same side.
- Sturge-Weber syndrome. A condition present from birth that is typically recognised by a port-wine birthmark on the face, often around the forehead, temple or eyelid. MedlinePlus Genetics estimates it affects 1 in 20,000 to 50,000 people; it is not inherited, and it can cause glaucoma and abnormal blood vessels in the eye on the same side as the birthmark.
- Other syndromes. AAO also lists Bloch-Sulzberger syndrome and von Recklinghausen disease (neurofibromatosis type 1) among the conditions that can be associated with heterochromia in infants.
Acquired causes (heterochromia that appears later)
AAO lists these causes of heterochromia that develops later in life:
| Cause | How it changes the iris colour |
|---|---|
| Eye injury, bleeding or surgery | Damage to the iris and blood or pigment released inside the eye can alter its colour; after some injuries with a metal foreign body, iron deposits (siderosis) can discolour the iris |
| Inflammation (iritis, uveitis) | Long-standing inflammation of the iris and the structures behind it can change its pigment |
| Fuchs heterochromic iridocyclitis | A chronic, low-grade, usually one-sided inflammation (see the section below) |
| Glaucoma medicines and Latisse | AAO lists glaucoma medications and Latisse (the bimatoprost product for eyelash growth). Prostaglandin-type glaucoma drops are known to be able to darken the iris in the treated eye, which becomes noticeable if only one eye is treated |
| Pigment dispersion syndrome | Pigment shed inside the eye changes the appearance of the iris |
| Iris tumours | A diffuse iris melanoma can cause progressive iris discolouration (see below) |
Fuchs heterochromic iridocyclitis (FHI)
Fuchs heterochromic iridocyclitis is the best-known inflammatory cause of acquired heterochromia. The AAO's EyeWiki describes it as low-grade, usually one-sided inflammation at the front of the eye with fine star-shaped deposits on the back of the cornea (keratic precipitates), iris heterochromia and prominent blood vessels in the iris and drainage angle. People often have no symptoms for years and typically present in early to middle adulthood. EyeWiki gives the following figures:
- Iris heterochromia is present in about 75% to 90% of cases, and the lighter iris usually marks the affected eye.
- FHI makes up about 2% to 11% of all uveitis.
- Cataract is particularly common, mostly of the posterior subcapsular type (three-quarters of the lens clouding in FHI).
- Glaucoma is the most sight-threatening complication, with reported rates of 9% to 59%.
Diagnosis rests on the clinical examination rather than a single test. EyeWiki notes that corticosteroids are generally ineffective for the low-grade inflammation in FHI. Cataract surgery with a lens implant is effective, and glaucoma may need surgery when drops are not enough (in the group EyeWiki cites, 73% did not respond to maximal medical therapy). Because FHI is so often found by chance, a new colour difference between your eyes is a good reason for an examination even if the eyes feel fine.
Iris melanoma and other tumours
Most iris spots are harmless freckles (naevi), but a rare diffuse iris melanoma can spread across the iris. EyeWiki reports that it can show up as progressive discolouration of the iris with loss of the normal crypts (the small pits in the iris surface) and pigment accumulating in the front chamber of the eye. Warning features include documented growth, a lumpy surface, a height above 2 mm and prominent blood vessels. Iris melanoma tends to be slow-growing: EyeWiki quotes metastasis rates of roughly 3% at 5 years, 5% at 10 years and 10% at 20 years. Small, non-growing lesions are watched with photographs and ultrasound; growing ones may be treated with radiation (brachytherapy) or surgery. Any iris that is darkening or changing in a localised area should be examined by an ocular oncology specialist.
What are the symptoms of heterochromia?
Heterochromia itself usually has no symptoms other than the colour difference. AAO says most infants with heterochromia have no other symptoms. The signs below point to an underlying cause and are the reason to be examined:
| What you notice | What it may point to |
|---|---|
| A colour difference that has been there since birth, with nothing else | Often a harmless variation, but ask for it to be checked once |
| A colour difference that is new or changing in a child or adult | Needs examination: injury, inflammation, medication effect, FHI or a tumour |
| Different pupil sizes, drooping eyelid | Horner syndrome or another nerve problem |
| Eye pain, redness, light sensitivity | Uveitis or glaucoma |
| Blurred vision, glare | Cataract (common in FHI) or inflammation |
| A pigmented spot that is growing or changing | Needs examination for an iris naevus or melanoma |
| White forelock, hearing loss, pale blue eyes in the family | Waardenburg syndrome |
| A port-wine birthmark on the face | Sturge-Weber syndrome |
If your eyes look different in other ways, such as one eye appearing to bulge or one eyelid sitting lower, that is a separate question from iris colour: see our guides to exophthalmos and ptosis.
Is heterochromia dangerous?
Heterochromia is not dangerous in itself, and the colour difference does not damage vision. Whether it matters depends on its cause and on when it appeared.
- Present from birth, no other signs: usually benign. AAO still recommends that an ophthalmologist perform a detailed eye examination for an infant with heterochromia to rule out an underlying cause.
- Appeared in childhood or adulthood: needs a full examination. AAO advises seeing an ophthalmologist if heterochromia develops or changes in adulthood, because the causes include inflammation, glaucoma, injury and tumours.
- With other signs (pain, redness, drooping eyelid, vision change, birthmark, hearing loss): arrange an assessment promptly. A sudden new pattern of a smaller pupil with a drooping lid, particularly with neck or head pain, needs same-day medical care.
How is heterochromia diagnosed?
Diagnosis is a clinical examination by an ophthalmologist, and AAO advises "a detailed eye exam" whatever your age. A typical assessment includes:
History
When the colour difference was first noticed (old photographs help, including childhood or passport photos), eye injuries or surgery, eye drops, family history, and any hearing, skin, hair or general health problems.
Slit-lamp examination
A microscope with a bright narrow beam to examine the iris, the cornea, the lens and signs of inflammation such as keratic precipitates.
Pupil and eyelid check
Pupil size and reaction and eyelid position, which can reveal Horner syndrome.
Eye pressure measurement and drainage-angle examination (gonioscopy)
To look for glaucoma, which can accompany FHI and several congenital conditions.
Dilated examination of the back of the eye
To check the lens, retina and optic nerve.
Photographs, ultrasound or scans, when needed
If a pigmented lesion is suspected, doctors record it with photographs and ultrasound and re-check it for changes in size and shape, as EyeWiki describes for iris melanoma. If Horner syndrome or a systemic condition is suspected, imaging may be arranged.
You can send us your recent eye reports, scans and a clear photograph of your eyes for an online opinion before you decide on anything.
How is heterochromia treated?
Heterochromia itself does not need treatment. Management is about finding and treating the cause. AAO states that when heterochromia exists in isolation, "no treatment may be needed."
| Situation | Typical approach |
|---|---|
| Benign heterochromia present from birth | Examination to confirm; no treatment; routine eye care |
| Fuchs heterochromic iridocyclitis | Monitoring; cataract surgery with a lens implant when the cataract affects vision; pressure-lowering drops and, if needed, glaucoma surgery. Steroids are generally not effective for the low-grade inflammation |
| Other uveitis (iritis) | Anti-inflammatory drops and, where needed, other medicines, guided by the cause |
| Glaucoma | Pressure-lowering drops, laser or surgery. If one-sided darkening follows glaucoma drops, discuss it with your eye doctor rather than stopping the medicine yourself |
| Eye injury or retained metal | Treatment of the injury and removal of the foreign body where appropriate |
| Iris naevus or melanoma | Photographic and ultrasound monitoring for small, stable lesions; radiation or surgery for growing tumours |
| Horner syndrome | Investigation and treatment of the underlying nerve-pathway problem |
| Waardenburg or Sturge-Weber syndrome | Care shared with other specialists (for example hearing and glaucoma follow-up) |
Can you change eye colour or "fix" heterochromia?
Not as a medical treatment, and it is not needed for a healthy eye. If you want to even out the look, coloured contact lenses are the usual option, but the US Food and Drug Administration (FDA) states that all contact lenses, including decorative ones, must be prescribed by a doctor, and that wearing lenses without a proper fitting can cause corneal scratches, infections and vision loss. Have the cause of your heterochromia checked before you consider any cosmetic change.
Treatment with us: Doç. Dr. Muhammet Derda Özer (uveitis, ocular oncology and cataract) and Prof. Dr. Ahmet Satıcı (glaucoma and cataract) can assess a colour difference together with the conditions that most often sit behind it, including cataract and glaucoma. If a cataract has developed, lens surgery is performed in a fully equipped, Ministry of Health–licensed operating theatre in Istanbul.
When to see a doctor about heterochromia
Seek same-day care from an eye doctor or an emergency service if:
- your eye colour changes suddenly and you also have eye pain, redness, light sensitivity or a drop in vision
- one pupil is suddenly smaller than the other with a drooping eyelid, especially with neck, head or face pain
- there has been an injury to the eye, particularly from metal or a fast-moving object
Book an eye examination soon if:
- your baby or child has two different eye colours, or one eye colour changes (AAO recommends an eye examination for an infant with heterochromia)
- you are an adult and your eye colour has started to differ, change or darken in one eye (AAO recommends seeing an ophthalmologist)
- you notice a dark spot on the iris that is growing, changing shape or becoming more raised
- you use glaucoma or eyelash-growth drops and notice one iris darkening
- you have heterochromia plus hearing loss, a white forelock or a facial birthmark
You are probably fine to follow up routinely if the colour difference has always been there, is the same in old photographs, and an eye examination found no cause.
Frequently asked questions
Heterochromia is a difference in iris colour, either between the two eyes or within one iris. It may be present from birth or develop later. It is often harmless when present from birth, but an eye examination is recommended to check for an underlying cause.
Not by itself, and it does not damage vision. The risk lies in its cause. A colour difference that has always been there is usually benign, while a new or changing one can be a sign of inflammation, glaucoma, injury, medication effect or, rarely, a tumour, so it should be examined.
Causes include genetic variation, mosaicism and chimerism, and conditions such as Waardenburg syndrome, Horner syndrome and Sturge-Weber syndrome. Acquired causes include eye injury or surgery, uveitis, Fuchs heterochromic iridocyclitis, glaucoma medicines, pigment dispersion syndrome and iris tumours (AAO).
Central heterochromia means the ring of iris around the pupil is a different colour from the outer iris, for example a golden-brown ring in a green or blue eye. It is one of the three patterns AAO describes, along with complete and sectoral heterochromia.
Yes, and a change in one eye deserves attention. AAO lists eye injury, surgery, inflammation, glaucoma medicines, Latisse, bleeding, Fuchs heterochromic iridocyclitis and pigment dispersion syndrome among the causes of heterochromia that develops later in life. See an ophthalmologist if your eye colour changes.
The colour difference itself usually does not need treatment. If there is an underlying cause such as uveitis, glaucoma or cataract, that is treated. Coloured contact lenses are a cosmetic option, but the FDA requires a prescription for them, including decorative lenses.
It can be. Some families pass sectoral heterochromia down generations in an autosomal dominant pattern, and genetic syndromes such as Waardenburg syndrome can cause it. Sturge-Weber syndrome, by contrast, is not inherited. If you are curious about how eye colour is passed on, try our eye colour chart and inheritance calculator.
Fuchs heterochromic iridocyclitis is a chronic, usually one-sided, low-grade inflammation at the front of the eye, with a lighter iris on the affected side in most people (75% to 90% according to EyeWiki). It often goes unnoticed until cataract or glaucoma develops, so regular checks matter.
Sources for the facts on this page
- All pages opened and checked on 7 Oct 2026.
- American Academy of Ophthalmology. What Is Heterochromia? https://www.aao.org/eye-health/diseases/what-is-heterochromia
- EyeWiki (AAO). Fuchs Heterochromic Iridocyclitis. https://eyewiki.org/Fuchs_Heterochromic_Iridocyclitis
- EyeWiki (AAO). Iris Melanoma. https://eyewiki.org/Iris_Melanoma
- MedlinePlus Genetics (US National Library of Medicine). Waardenburg syndrome. https://medlineplus.gov/genetics/condition/waardenburg-syndrome/
- MedlinePlus Genetics. Sturge-Weber syndrome. https://medlineplus.gov/genetics/condition/sturge-weber-syndrome/
- Tomar M, Dhiman R, Sharma G, Yadav N. Artistic Iris: A Case of Congenital Sectoral Heterochromia Iridis. J Ophthalmic Vis Res 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6058536/ (PMID 30090196)
- Deprez FC, Coulier J, Rommel D, Boschi A. Congenital Horner syndrome with heterochromia iridis associated with ipsilateral internal carotid artery hypoplasia. J Clin Neurol 2015. https://pmc.ncbi.nlm.nih.gov/articles/PMC4387487/ (PMID 25749818)
- US Food and Drug Administration. Decorative Contact Lenses. https://www.fda.gov/medical-devices/contact-lenses/decorative-contact-lenses-halloween-and-more
Noticed a colour difference between your eyes, or a change in one eye?
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