# Human Eye Color: Variations And Genetics Behind **URL:** \ **Category:** General\ **Created:** [October 21, 2026, 5:56pm UTC](https://www.medboundhub.com/t/human-eye-color-variations-and-genetics-behind/24022 "2026-10-21T17:56:13Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![dr\_sneha\_p](https://yyz1.discourse-cdn.com/flex033/user_avatar/www.medboundhub.com/dr_sneha_p/32/6094_2.png) [@dr\_sneha\_p](https://www.medboundhub.com/u/dr_sneha_p)\ **Post date:** [October 21, 2026, 5:56pm UTC](https://www.medboundhub.com/t/human-eye-color-variations-and-genetics-behind/24022/1 "2026-10-21T17:56:13Z")
![Variations in eye color happen due to difference in genetics and amount of pigments produced](https://canada1.discourse-cdn.com/flex033/uploads/medbound/original/2X/0/07e7ed75d69ab9795a043d4a716cbdc6a4a96113.jpeg) _Have you ever wondered why there’s wide variation in eye color among people or how these different colors come to be? Here’s a complete breakdown of the science behind eye color variations._ ## How is eye color created? The colored part of our eye, the iris has 2 layers – the epithelium (front layer) and stroma (back layer). The variation occurs in the stroma. The stroma contains collagen fibers and melanocytes (pigment-producing cells). The number of melanocytes depends on genetics and varies among people. Furthermore, the pigments produced are of 2 types – eumelanin and pheomelanin whose concentrations varies among people according to genetics. The combination of these factors along with the way light interacts with the iris structure determines whether a person has blue, green, brown, hazel or grey eyes. ## The genetics behind While many genes contribute to eye color, two genes on chromosome 15 play a key role– OCA2 and HERC2. OCA2 gene produces a protein involved in building melanosomes (the tiny compartments where pigment is produced and stored). The more active the gene is, the more [melanin](https://www.medboundhub.com/t/understanding-albinism/8546) the iris produces. HERC2 gene controls the OCA2 gene – it’s variation influences OCA2 activity, reducing pigment production and resulting in lighter eyes. Apart from these two, additional genes fine-tune the shades. This explains the wide spectrum of intermediate eye colors: steel blue, gray, green, hazel, amber and every shade in between. ### Source: [Why Do People Have Different Eye Colors? - ScienceInsights](https://scienceinsights.org/why-do-people-have-different-eye-colors/) > #### Do you know about heterochromia? Why it happens? MBH/PS ---
**Author:** ![Aniket](https://yyz1.discourse-cdn.com/flex033/user_avatar/www.medboundhub.com/aniket/32/1834_2.png) [@Aniket](https://www.medboundhub.com/u/Aniket)\ **Post date:** [October 21, 2026, 7:16pm UTC](https://www.medboundhub.com/t/human-eye-color-variations-and-genetics-behind/24022/2 "2026-10-21T19:16:45Z")
It occurs when a person has two different eye colors either in each eye or within the same eye. It can be genetic, present from birth, or develop later due to injury, inflammation.