Heterochromia Iridis is the Greek term for "differently colored irises." More commonly called heterochromia, because the term describes two different colored eyes that are on the same being. Heterochromia is more common in cats. Instead of calling this condition heterochromia, the term often used to refer to cats is "strange eyes." Alongside heterochromia, however, it is known to be linked to other disorders, such as deafness, to which cats with strange eyes may be more vulnerable. While heterochromia is usually present when the disorder; deafness is detected, heterochromia in cats does not stimulate hearing loss as normally would, because the way the mutation develops does not contribute to the related disease, some breeds are more susceptible to heterochromia with other associated disorder, and a known condition (hearing loss) linked to cats with heterochromia. The mutation develops based on the amount of melanin, the pigment that makes our skin darker in the sun, which also determines eye color in humans and cats. While all kittens are born with blue eyes, as the kitten grows, the melanin is transferred to the iris of the eye. If the melanin is not transferred, the eyes will remain blue. However, if melanin only spreads in one eye, the result will be heterochromia; one blue eye and another ranging from yellow to brown (Cats with two eyes of different colors). A lack of melanin does not contribute to major disorders as is believed; deafness occasionally appears in cats with heterochromia. It is estimated that 60-70% of odd-eyed cats do not suffer from hearing loss (cats with two different colored eyes). Breeds more susceptible to heterochromia are generally white or predominantly white cats. . Bre...... middle of article....... Heterochromia cannot be the cause of another disorder, because it is already the product of an incident itself, which does not This probably only caused the other disorder to appear. Prue. “Disorder – Waardenburg Syndrome.” sydney.edu.au. LIDA. Internet. February 21, 2014Dennis-Bryan, Kim. The Complete Book of Cat Breeds: Dorling Kindersley, 2013. Print.Hickman, Gayle. “Cats with two different colored eyes.” petsadviser.com. October 21, 2012.Web. February 9, 2014. Quay, Claudia. “Disorder – Iris Defects.” sydney.edu.au. LIDA. Internet. February 9, 2014. RW, Guillery. “Do blue-eyed cats have normal or abnormal retinofugal pathways?” iovs.org (Investigative ophthalmology and visual sciences). Internet. February 21, 2014. Strain, George M. “Congenital deafness in dogs and cats.” » Compend Contin Educ Pract Vet 13(1991): 245-250. Google Scholar. Internet. February 9 2014.