Factors Influencing Binocular Vision in Children with Successful Surgical Alignment of Esotropia
|Keywords||Esotropia Children Fusion Stereoacuity|
BACKGROUND AND OBJECTIVE:Binocular vision is the cortical phenomenon that gained by unifying the separate retinal images and integrated by the isual cortex. Binocular vision is a high level, perfect performance of people understand the environment. The formation of binocular vision must meet the conditions of the first two requisites of straight eyes and similar retinal images before3years old. With age increasing, the time prolonged, the strabismus increasing, the binocular vision was damaged seriously. This fact has led to early treatment of constant strabismus, especially monocular amblyopia, anisometropia and so on. Esotropia is the most common strabismus type in children. To investigate the binocular vision achieved in children after successful surgical alignment of esotropia and to identify clinical factors that may associated with the outcome.METHODS:Consecutive111children cases with esotropia who underwent unilateral medial rectus recession or bilateral medial rectus recession(the cases with oblique muscle hyperthyroidism underwent oblique muscle recession) from Nov,2008to Sep,2011in the department of Ophthalmology in Shandong Provincial Hospital were retrospectively reviewed. The cases surgically aligned within8PD of orthotropia during the follow-up period. Each patient underwent detailed ophthalmologic and orthoptic examinations before the operation, including naked vision and best corrected vision, cycloplegic refraction, motility evaluation, anterior segment assessment and fundus examination. The children with hypermetropic refractive error greater than2D must wear glasses at least3months and the children with strabismic amblyopia must undergo cover treatment. Surgical treatment take place when the children’s vision of two eyes less than2lines. The strabismus degrees were measured by the alternate prisms cover test at both distance (6m) and near (33cm) and told the children fixation on the accommodative targets.Worth4dots Flashlight test was used to evaluate the central(2meters) and peripheral(33centimeters) fusion of the children after successful surgical alignment of esotropia, and Titmus stereogram was used to evaluate the stereoacuity. All surgeries were performed by the same surgeon. The follow-up time is1week,6to8weeks,6months and once every6months later. We record the establishment of binocular vision function according to the final follow-up results.RESULTS:(1) Of the111children with successful surgical alignment of esotropia, sixty-eight (61.3%) acquired peripheral fusion, six (5.4%) acquired central fusion, fifty-six (50.5%) achieved different degree of stereoacuity.(2) The age at the operation (P<0.001), the treatment duration of the amblyopia (P<0.05), and the alignment at the last follow-up (P<0.05) showed negative correlations with the postoperative peripheral fusion. There was no significant correlation between anisometropic equivalent of the two eyes and postoperative peripheral fusion (P>0.05).(3) There is statistically significant (χ2=15.977, P=0.001) since it will be made differences of the postoperative peripheral fusion when achieved in the different types of esotropia. The congenital esotropia was least likely to achieve the peripheral fusion (OR=1.0), followed by non-accommodative esotropia (OR=3.008), partially accommodative esotropia (OR=4.475), and the high AC/A ratio esotropia (OR=82.217).CONCLUSIONS:(1) The earlier age to obtain successful surgical alignment, the shorter duration for treatment of amblyopia, and the smaller angle of orthotropia after surgery led to the more probability to achieve the peripheral fusion.(2) The congenital esotropia was least likely to achieve the peripheral fusion, The diffculty degree of achieving the peripheral fusion ranks by congenital esotropia, non-accommodative esotropia, partially accommodative esotropia and the high AC/A ratio esotropia.