I've got an eight year old daughter who we noticed at the age of 3 doing the same (but one eye turning in)she would also close that eye and just look with the other, if we had shown her something close up. Then she started bringing her chair right in front of the tv to watch, and after repeadtedly asking her to move back she said I can't see it from there mom. To the eye doctor that week we went, and she has been wearing glasses since. Her eyes have definately improved over these 5 years, if for some reason she has her glasses off, it is rare to see the eye turn now. As children grow their eyes change, so glasses may not be forever. Watch for more signs of strain and ask him about how he is seeing not if he feels the eye turn, the eye sends a signal to the brain and essentially tells the brain to turn the eye off, and they (without even knowing) use the "good eye" to see. You could see your pediatrician and he can refer you to an opthamologist. We had Dr. Gilligian @ Manchester Eye Assoc. on Second St in Manchester, and she was so good with my daughter, she has an 8 year old boy and a 5 year old girl so she's a mom too, she had my daughter at such ease, right from the start and at 3 that was sooo important to me we were both a little scared. We had to change doctors because our insurance changed and I was sad to go, she let's you sit right in there even with the lights off during all the tests so I I saw for myself the weakness in her sight etc. You'll feel better when you get to the bottom of it, your little guy may not see as well as he could.