In the clinic, we sometimes encounter young parents who bring their children who are a few months old to the clinic and the first thing they ask the doctor is, “Does my child have crossed eyes?” Like the child in this photo, does it look like a cross-eyed child? （In fact, this child’s eye position is normal, and the reason it looks like an internal strabismus is because she has redundant skin in the inner canthus and the pupil distance is too close, which we call “pseudo-internal strabismus. This condition will gradually improve as the child grows older and her face develops further, and does not require special treatment. Let’s take a look at the following picture: this is a clear case of internal strabismus, which requires detailed examination to confirm the type of strabismus and provide timely treatment. To the ophthalmologist, strabismus not only affects the aesthetics, but more importantly, it impairs the visual function of the child, including: simultaneous vision, fused vision and stereopsis. In layman’s terms, the child’s two eyes cannot see simultaneously to form a correct image in the brain, and their visual world is overlapping and confusing.