Xiao Xi just turned 1 year old and started to “tease her eyes” when she was 4 months old. Her mom and dad took her to the local hospital and recommended that she be treated when she was older. Today, her parents brought her to my clinic. First, I checked the eye position and found that although the child’s internal obliquity was very obvious, she could alternate her gaze with both eyes, which meant that she had balanced vision in both eyes. Bilateral eye movements: The eye movements were smooth. Next, our optometrist examined the child and both eyes were +1,00DS, with no significant hyperopia. Both eyes were physiologically hyperopic. It was recommended that an internal oblique surgery be performed as soon as possible to save the visual function of both eyes. The parents feel incomprehensible. Is it too early to operate when the child is too young? Will the examination be cooperative? What tests are needed? When is the best time to operate. I will now give you a systematic introduction. 1.What tests are needed for pediatric strabismus? Less than 3 years old: If there are obvious refractive abnormalities, pupil dilation with atropine eye ointment is required for optometry. Routine strabismus degree examination, eye movement examination, and trigeminal examination. Greater than or equal to 3 years of age: If the child can recognize letters or numbers, the child’s vision can be checked. All children will need a refractive error examination. If there is an internal strabismus, all children need to have an atropine dilated eye exam. In the case of exotropia or vertical strabismus, atropine dilation is required if there is hypotropia or refractive abnormalities. As the child’s comprehension increases, in addition to routine strabismus examination, eye movement, and trigeminal examination, we can also perform synoptic and stereopsis examinations to understand the child’s tertiary visual function (simultaneous vision, fusion, and stereopsis). 2.When can I bring my child in for strabismus examination? Normally, the macular function of both eyes is fully developed at 4 months after birth in a full-term child. This means that the child’s eyes are in the right position at 4 months of age. If strabismus is still present at this time, it needs to be considered a true strabismus. Therefore, it is recommended that parents who have doubts about their child’s eye position should bring their child to the clinic for examination after correcting the gestational age of 4 months (gestational week at birth plus days after birth). 3.When is the best time to operate for pediatric strabismus? For congenital internal strabismus, experts suggest that surgery is best before the age of 2 to allow for the formation of peripheral coarse stereopsis. For ophthalmic strabismus (superior oblique muscle paralysis), if the degree can be identified after diagnosis, surgery should be performed as soon as possible. We have operated on the youngest child with superior oblique palsy at the age of 7 months. On the second day after surgery, the head position was immediately corrected. Why did the physician insist on early surgery when it was extremely difficult to examine the child? Because long-term head tilting can cause small and large faces and scoliosis in the child. This cannot be restored even after strabismus correction, i.e., after the head position is corrected. However, early surgery can prevent these occurrences. In children with intermittent exotropia, surgery is usually performed after the age of 4 years. In particularly severe cases, earlier surgery may be appropriate. If refractive errors are present, they should be treated with glasses as early as possible to avoid aggravation and deepening of exotropia. If a child appears to have a sunlight happy closed eye, it means that the fusion function is destroyed and early surgery should be performed. If the frequency of exotropia is found to increase, the degree of aggravation needs to be operated as soon as possible to avoid the loss of stereoscopic function. 4.When can I bring my child for strabismus examination? Under normal circumstances, the macular function of both eyes of a full-term child is fully developed at 4 months after birth. This means that the child’s eyes are correctly positioned at 4 months of age. If strabismus is still present at this time, it needs to be considered a true strabismus. Therefore, parents who have questions about their child’s eye position are advised to bring their child to the clinic for an examination once the gestational age has reached 4 months (weeks of gestation at birth plus the number of days since birth).