Susan J. Gross, co-director of the Division of Reproductive Genetics at the Montefiore Medical Center and an associate professor at Albert Einstein College of Medicine, provides this explanation.
Eye color is a manifestation of the pigment that is present in the iris. Brown eyes are rich in melanin deposits, and blue eyes indicate a lack of melanin. The melanocytes of the iris rest in a richly innervated psuedosyncytium, which is necessary to maintain eye color. Two genes control eye color: EYCL3, found on chromosome 15, which codes for brown/blue eye color (BEY), and EYCL1, found on chromosome 19, which codes for green/blue eye color (GEY). Although previously believed to be inherited in simple Mendelian fashion, eye color has proved to be a polygenic trait. Precisely how these genes interact to provide the full constellation of colors, such as hazel and gray, is as yet unknown. Furthermore, other genes may determine the pattern and placement of pigment in the iris, thereby accounting for solid brown as opposed to rays of color.
 HETEROCHROMIA IRIDIUM is depicted in this photo illustration. |
Heterochromia iridium (two different-colored eyes within a single individual) and heterochromia iridis (a variety of color within a single iris) are relatively rare in humans and result from increased or decreased pigmentation of the iris. Most cases are isolated and sporadic, conceivably resulting from an alteration in the expression of the above-mentioned genes (and those we have yet to find) within the cells of the entire iris or even a particular section. Other potential causes include trauma around the time of birth or later in life, congenital pigmented nevi or even medications such as those used in the treatment of glaucoma. There are a few well-known syndromes of which heterochromia iridis is a striking feature. Waardenburg syndrome type 1, an autosomal dominant disorder caused by mutations in the PAX3 gene, is characterized by pigmentary disturbances of the iris, hair and skin, as well as congenital sensorineural hearing loss. But two different eye colors tends to be an isolated finding, which adds to the seemingly endless and fascinating variation in humans' physical characteristics.
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24 Comments
Add CommentI have a brown eye and a blue eye I was born with blue eyes and before I was one week old my left eye turned brown. They are completely different my brown is very brown and my blue eye is a shade of bright blue. I can see I can hear, Im just very curious about the subject, and wonder why this happened. I get lots of complements about this and people ask why so I am looking for a simple explanation other than I am special.
Reply | Report Abuse | Link to thisHi my name is Rafael Arce, and I too have the same condition. I was born with blue eyes. Then they turned hzl, but now my right eye is green and my left is blue. I really didn't pay much attention to my until people and family began the to notice a change in my eye color. No complaints of course, but I would like to know if there's something going wrong with me or do I need to seek medical attention. Thank you.
Reply | Report Abuse | Link to thisI also have the same condition. When I was born I had a green and a blue eye. It was not until I got up in age that my left eye turned hazel. In my hazel eye there is a pie peice that is blue and my parents told me that it has always been like that. I am very curious as to why I was born like this. My father's father also had the same condition.
Reply | Report Abuse | Link to thisMy eldest grandchild was born with different color eyes but his pupils are two different sizes also. Is this a familiar difference with this condition. we had him too a eye specialist when younger and he told me he would send us a diagnosis but he never did . He did however say it had nothing to do with his vision . ( which he is severely far sighted now) both parents do wear glasses . Ansd that the only thing we could do was get contacts for the cosmetic purpose which we won't because we love his blue and green eye. It is a chick magnet he says he is 9 lol.
Reply | Report Abuse | Link to thisi believe people who have heterochromia or two differnt colored eyes (like myself; blue and most brown with blue) are special! i believe our uniqueness and rarity not only get us attention, they encourage us to see things from different perspectives! i believe its a blessing really :)
Reply | Report Abuse | Link to thisMy son is 8 weeks old and was born with one blue eye and one brown eye. The doctors have told me its nothing of concern however it makes me nervous. Since his birth he has been vomitting without cause. He has been hospitalized twice. They ruled him out for Hirshburg's disease. He has gone thru spinal taps, head CT, bloodwork including metobolic profiling, Ultrasound of Abdomen and everything has been negative. When i searched for Heterochromia on the internet it told me of rare disorders associated with it. Now I am wondering if there is a possibilty of something else. My son has seen numerous doctors (none specializing in eyes) and they told me its nothing to worry about when it comes to eye color. If anyone has any suggestions/or has a similar story please let me know. Thanks
Reply | Report Abuse | Link to thischanging of the eye color usually happens within the first week . Its caused by lost of eye pigment(pigment=color). It is usually genetic and runs in the family like far sightedness or wearing glasses(like my family).
Reply | Report Abuse | Link to thisMy names is Samantha I am 20 Years old. I have One bright blue eye and one dark green. I have always wondering why My Eye color was so werid. On my ID the state of Idaho put "DIC" (Different in Color). That was the first time I realized that it was uncommon. So I was wondering If, there is a simple answer minus, lack on pigment. I love that its different but I have very Few real reasons for the difference from one eye to another.
Reply | Report Abuse | Link to thisHey! I was curious about this subject too as i was born with a green eye and a brown eye. When i researched this, it seems that the common reason for eyes being two different colours is that one eye does not contain any melanocytes. This means one eye is blue and the other a different colour. Im still researching what the reason for my eye colour is but some of the information is quite scary i.e chimera and mosaic dna.
Reply | Report Abuse | Link to thisHi! My name is Kayla. Im only 12 Years old and i have one blue eye and my other eye is blue and brown. Lots of people ask me if i have contacts but i dont i was born this way. isnt blue eyes and red hair mutations? well i have both...
Reply | Report Abuse | Link to thisim 23 and i have one dark green eye and one dark brown eye with black rings why are my eyes like this
Reply | Report Abuse | Link to thisim 23 and i have a dark brown eye on the right and my left eye is dark green they have a black circle around them both i didnt notice till i was in school when a few people kept saying it to me why are my eyes like this
Reply | Report Abuse | Link to thisI was curious about this,
Reply | Report Abuse | Link to thisI'm 14, my eyes were bright blue until my left eye started to change to a green, then went hazel and now it is a brownish colour with a bit of grey on the top, i wasa told i have a spider nevus on the back of my eye.
Hi my name is jessica. I was born with two brown eyes, but just recently my right eye started turning green and now on most days its a bright green while the other is a brown is this the same thing as heterochromia iridium or does it only apply to one brown eye one blue eye?
Reply | Report Abuse | Link to thisMy son who is now three was born with one blue eye and one that is brown and blue. He also began vomiting forcefully at around three weeks. He ended up having pyloricstenosis. It was fixed with a surgery, he hasn't had any issues since.It is most common in first born males with O- blood.
Reply | Report Abuse | Link to thisMy above comment was in reply to SusieRN76.
Reply | Report Abuse | Link to thisi have one brown eye and one golden hazel eye usually people dont notice unless they look right into my eyes
Reply | Report Abuse | Link to thisI'm Matt, I'm only 11, and I was born with fully blue eyes. Now, my right eye is blue still, a similar shade as I was born with, but my left is mostly blue of the same shade. The other part is a significantly lighter grey. I heard it can be genetic, caused by tumors, eyedrops, but my doctor hasn't told me I've got it yet. I strongly believe I do.
Reply | Report Abuse | Link to thisThis is wrong heterochromia iridium is wrong the correct term is heterochromia iridum or iridis and they are both the exact same thing. Complete heterochromia is where both eyes are completely different colours. eg one brown one blue and partial or sectoral heterochromia is when one eye is different colours. even check http://heterochromiacentral.com or wikipedia
Reply | Report Abuse | Link to thisI have both, upon closer inspection. One of my eye is a green-blue, my other is half blue half green. How strange.
Reply | Report Abuse | Link to thiswell i have hazel eyes and i am 15 and my left eye is brown on the inside and green on the outside, and my right eye is brown on the inside and blue on the inside. I find this really strange. My friends think i wear contacts but i don't and if my eyes are in the sunlight they go fully green.
Reply | Report Abuse | Link to thismy name is Dustin Smith, i was born with hazel blue eyes. But,resently my left eye turned hazel green. so, now my left eye is hazel green and my right eye is hazel blue.
Reply | Report Abuse | Link to thisHi, my name is Caitlin and I was wondering. I don't have two different colored eyes, but I do have, I guess you can say, different colors in each eye. My general eye color is a hazelish-blueish color, but right at the center, around my pupil, there is an area of bright orange. Are different colored eyes and different shades of color in each eye connected in anyway, or am I just speculating?
Reply | Report Abuse | Link to thisHi my names Rachael im 25 when i was born i had blue eyes as i got older and got my first boyfriend. he noticed my eyes was two different colours one blue one green i was shock and as well worried weather it could be anything medical. but like tonipmct says we are special! i believe our uniqueness and rarity not only gets us attention, they encourage us to see things from different perspectives! i believe its a blessing really :)
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