How to distinguish between true and false “crossed eyes”? Internal strabismus is commonly referred to as “crossed eyes”. Many children with similar strabismus are seen in clinical practice, but in fact have a normal eye position. What parents perceive as “crossed eyes” in children is known medically as common internal strabismus. It is important to distinguish between true and false “crossed eyes”. (1) False “opposite eye”, i.e., pseudo-intraocular strabismus, is more common in clinical practice and can be formed for several reasons: first, the inner canthus, or the low nasal bridge and wide skin at the back of the nose in young children, are common reasons for mistaking “opposite eye” for “opposite eye”. Because the redundant skin covers the inner canthus of both eyes, the sclera on the nasal side is less exposed than on the temporal side, thus giving the illusion of an internal obliquity. Identification method: After pinching up the skin at the root of the child’s nose, the sclera on the nasal side will be exposed more, and when the eye position is observed, the “internal obliquity” will disappear. The other type is children with small pupil distances, which can also give the illusion of “opposite eye”. If the pupil distance is less than 55 mm in adults, it can also be mistaken for “opposite eyes. This type of pseudo-exotropia can also be distinguished by observing the corneal reflection points. (2) Pseudo-exotropia. In normal people, the distance between the inner canthus of the eyes and the width of the lids of the two eyes is roughly divided into three equal parts, but if the nasal root is too narrow, people may mistakenly think that the pupil distance is large, causing the illusion of exotropia. Observation of the corneal reflection point can determine if there is a true exotropia.