This is one of the questions that comes up very often in the Little Four Eyes facebook group. The question usually reads something like this:
My child just started wearing glasses a few weeks ago for farsightedness. Before getting glasses, we noticed that her eyes would cross, but only occasionally. When her glasses are on, her eyes are staying straight now, but now when we take her glasses off, her eyes always cross, and it seems like they’re crossing even more than they used to. Are her glasses making her eyes worse?
It has always frustrated me that this isn’t covered by more eye doctors with parents of farsighted children. Short answer is that it is nothing to worry about if a child’s eyes are straight with glasses on, but crossing without glasses, in fact it’s quite common. However, it’s very startling and upsetting for parents to see what looks like their child’s eyes getting worse after they get glasses.
This happens with kids with accommodative esotropia. That is, their child uses their accommodative reflex to focus through the farsightedness, but that causes eye strain and crossed eyes. Monica Wright from Kids’ Eyes Online has a good overview.
Once a child has adjusted to their glasses, they become used to seeing clearly. When their glasses are taken off, they want to continue seeing clearly, and so they try to accommodate, which causes their eyes to cross, often more strongly than before they had glasses.
We saw this with Zoe (as you can see in the pictures), and it was really upsetting to see, especially since I so strongly associated crossed eyes with vision problems. As Zoe has gotten older, she’s been better able to keep her eyes straight even without her glasses.
It is also important to note that if you see your child’s eyes not lining up correctly while their glasses are on, you should contact their eye doctor. For many children, it’s a sign that their prescription needs adjusting.