When Will My Baby’s Eyes Change Colour?
It shouldn’t be surprising that a baby’s eye colour is a very popular conversation topic with parents. “Most precious sense”, “windows to the soul”, and “the eyes have one language everywhere” are age-old quotes that indicate our long fascination with eyes.
So what causes eye colour? Generally light coloured irises are from an absence of pigment, where as a brown iris has pigment deposited on the surface. Many babies are already born with this pigment in place so the colour will not change. Any changes that do occur involve a darkening of eye colour over the first 12 months due to more pigment being deposited on the iris surface, with little change after this.
Classification by colour can be as simple as blue, green, hazel or brown. Or more complex like light blue, darker blue; blue with brown peripupillary ring, green, green with brown iris ring, peripheral green central brown, brown with some peripheral green, brown, and dark brown – phew! Classifying colour is one thing, predicting eye colour is another.
Eye colour is determined by our genes, with most models centring around blue vs brown. The simple blue-brown model has brown determined as the dominant colour and blue as a recessive colour. This means if you have brown eyes you can either have two dominant brown genes or one brown and one blue. Blue eyes can only happen when two blue genes occur together. So a baby is unlikely to be brown-eyed if both parents are blue. However it is possible for a child to be blue-eyed if both brown-eyed parents each carry the recessive blue gene. If you want to predict eye colour other than brown or blue, the genetic models are not so simple!
Should parents be concerned about eye colour? From an eye health perspective, significant changes in eye colour are rare after the first 12 months. Any changes to only one part of the iris or to one eye only can be signs of eye disease irrespective of age, so if you notice a change then it is worth having an assessment done. We recommend routine vision tests at 6 months, 3 years and annually for early primary school children.