Strabismus is one of the most frequent ocular problems among developmentally normal children. The prevalence of strabismus varies among different regions, ranging from 0.06% in Japan to 5.65% in China. Exotropia is reported to be the most prevalent type of deviation in many of these studies. About 48-92% of the exotropic patients have intermittent exotropia (IXT). Jenkins reported that the prevalence of exodeviation was higher in countries near the Equator. Its prevalence is also higher in subequatorial Africa, the Middle East, and East Asia (where there is plenty of sunshine) in comparison to the USA and Central Europe. Intermittent exotropia is a disorder of binocular eye movement control, where one eye intermittently turns outward. The outward deviation is greatest and likely occurs at far distances viewing, when the oculomotor convergence effort is weakest, and occurs frequently when the patient is under stress, tired, ill, or in particular test situations. X(T) can also occur at near as convergence insufficiency.

Inclusion Criteria:

• patients diagnosed with 8 prism diopters or more exodeviation at distant or near fixation, regardless of age or fusion control (including exophora, intermittent exotropia, and constant exotropia).

Exclusion Criteria:

• patients with congenital ocular anomalies or ocular mayopathies. Patients with limitation of ocular motility resulting in strabismus, including neurologic or paralytic disorders, previous ocular surgical history, including strabismus and visually affecting surgeries, or any conditions affecting the central visual acuity, including anterior segment abnormality, cataracts, retinal diseases, or blepharoptosis (ocular sensory disorders), were excluded. When a patient was suspected to visit multiple institutions

Egyptian population