change could be due to problems on the cornea such as arcus or scarring. The iris can change color due to injury, inflammation, or other diseases within the eye.
See an ophthalmologist to find out why. Take in an old color good picture of your face that shows your iris color "a long time ago"
JCH MD
Some people's eye color seems to modify with age. My brother's, which was dark brown, has faded to light brown. My sister's and my daughter's eyes were light brown and are now hazel. Their eyes are healthy.