What Causes Eye Color Change?
Eye color can change over time because of age or, unfortunately, disease. Aging, however, is the usual cause of color change over time. It does so for 10 to 15% of the normal Caucasian population. These people’s eyes change slowly over many years after they reach adolescence. Some eyes become darker, but most become lighter with increasing age. How and why eye color changes. Pigment in the front layer of the iris (called the stroma) colors the iris. Eye color lightens when pigment granules drop in number, or when the granules make a lighter color. See figure. The iris can also lose color if the pigment degrades.
