I have noticed this peculiar effect all my life, but people I tell usually think I am bonko. My eyes change colour when exposed to strong sunlight for a day or two. They are normally hazel with a faint green background. After a few days in bright sunlight in Thailand last week-end, they were definitely green, and brighter than a couple days previously. The change is visible indoors or outdoors in all manners of light, and persists for days after my exposure.
The colour of my eyes is essentially intensified. Details: I am olive-skinned, dark-haired, mediterranean, and 26 years old. Slightly myopic. Does anyone have a medical explanation for what takes place? Are my eyes suntanning? Am I suffering damage from UV rays?