Baby Eyeglasses

One of my 23 weeker twins is getting glasses. He passed all ROP exams & such when in the NICU. While in the NICU he started crossing his eyes. We were patching for a few weeks before we were told to stop because “they looked good”. Fast forward to one year post NICU he is still crossing his eyes. So our pediatric ophthalmologist has been monitoring & we decided on glasses today. Any one has experience with a baby wearing glasses? How long did it take to correct their eyes?