AP Mom to 5
hey kittywitty! My oldest has the same. She is seven years now. I noticed it when she was an infant, and it really freaked me out as I thought maybe she had had head trauma somehow without me noticing (right!), but the docs said that some people just have a pupil that is larger than the other. Her eyes still dilate unevenly in the dark (not so much in bright light), but her vision seems fine. Just a little quirk. Probably it's nothing to worry about, but good that you will get it checked soon.
Hi there, thought I would chime in because my son is the same! I also noticed it around the same time as you noticed the difference in your LO. Because he seemed fine, I waited to discuss it with the doctor at our 2-month well baby visit. They didn't necessarily feel there was anything wrong, however they did refer me to a pediatric opthamologist. The opthamologist examined his pupils and gave him drops to dilate them, but in the end felt that it was likely that he simply has different sized pupils rather than an underlying condition causing the difference. But we do have a follow-up appt at 6 months just to make sure nothing has changed. The opthamologist told me that I should call for a sooner follow-up if I notice his smaller-pupil eye changing in color, particularly if it gets lighter than the other eye. However, my DS is 18 weeks now and there has been no change and he is hitting all of his developmental milestones.
So, I wouldn't worry if I were you, but if you are offered a referral, I would do it. Just for piece of mind. However, if you are referred to an opthamologist, make sure they specialize in peds NOT adults.
AP Mom to 5
My 4 yo daughter has the same thing, and we noticed it when she was five months (ped never noticed it either). Looking back, it was so obvious in her pics I am surprised we didn't notice it sooner. She had the full eye exam shortly after that, and she just has one pupil bigger than the other (it's called physiological anisicoria). We were terrified it was some terrible tumor of course, but it's just one of the quirks in our sweet little girl.