hmm i have heard of this topic a little before
maybe google has the answer
....
*dramatic arnold schwartz accent*
I'll be back
(from mikefrom from yahoo answers)
What determines eye color is the pigment melanin.
Eyes that have a lot of it in the connective tissue at the front of the iris, called the stroma, are darker, while those that have less tend to be lighter.
The levels of melanin generally remain the same throughout life, but a few things can change them permanently.
one cause appears to be genetics. A study in 1997, for example, looked at thousands of twins and found that 10 percent to 15 percent of the subjects had gradual changes in eye color throughout adolescence and adulthood, which occurred at nearly identical rates in identical twins.
You might try this; make a log of what you eat, how often you're in the sun, if you have physical activity, or anything else you can think of, to keep track of what things affect your eye color. I'm guessing you're growing fast if they're changing so often, that's very weird. Watch out for foods containing monosodium glutamate otherwise known as spice, spices, natural flavorings, flavorings, msg. This most potent preservative may effect eye color and even blur vision since it will preserve cell tissue and cause them to die off in a sort of domino effect. Chocolate blurs the vision, and does the same as above on a small scale, so do hydrogenated oils. There should be no substitute for a healthy balanced diet of fresh unprocessed food. When it comes to melanin production you will find that both metabolism and what you eat and how much you eat greatly affects what you eye color may be. Your eyes completely heal every 24 hours, so sun damage and low melanin is most likely the main cause if you get a new color for cloudy days.
here's the link if you guys want to read more
http://answers.yahoo.com/question/index?qid=20080912123919AAYxPaS