Dark area in our baby's light blue eyes?

My husband has light blue eyes, I have "orange"-green-blue. Our first two children have bright/light blue eyes, our newest baby (almost four months old) also has bright blue eyes, but has suddenly developed a large spot of brown in her right eye, just above the pupil. It developed within two days, and goes from about "11:00 to 2:00." This has me newly interested in iridology. Any comments would be very welcome! Thanks. Tweet