Esotropia of a particular kind called AACE frequently comes with diplopia, which interferes with visual performance and quality of life. AACE is more common in older children than adults in recent years22. The etiologic tracing of 101 patients in this study did not identify any of the cranial lesions or monocular occlusions that were frequently reported in earlier reports. Therefore, to identify the differences between adolescent and adult AACE in terms of clinical characteristics, we carried out a comprehensive investigation for individual subjective symptoms and binocular visual function.
Previous studies reported that AACE patients showed underlying or concurrent neurological pathology23–25. These findings support the conclusion that neurological disorders can cause acquired coexisting AACE, but that in the majority of cases, the cause is benign. No subject in our study had a known neurological disorder. By the way, there aren't any Swan type AACE patients in our study, which is AACE brought on by a sudden fusion dysfunction due to monocular vision loss or occlusion. Contrary to some earlier investigations26,27, early studies showed that prolonged occlusion leads to the development of AACE in patients with anisometropic amblyopia28,29. Due to fusion function, this kind of AACE typically affects patients who have esophoria but do not exhibit esotropia. Once the fusion function is destroyed, the esophoria cannot be regulated and transforms into esotropia. It is particularly common in youngsters with monocular amblyopia who have to occlude healthy eyes. It is simple to cause AACE when one eye is covered. We may not have found Swan AACE because none of the participants in this study had a history of amblyopia or monocular covering.
The findings revealed a negative correlation between age and SE of both eyes, and angles of deviation at near and at distance, whereas a positive correlation was found between age and disease duration, fusion, and distance stereopsis. This indicated that a prolonged course of ocular maturity is accompanied by the disease-lasting, smaller angles of deviation and showed relatively reduced opportunities for binocular vision to loosen. The condition typically manifested itself in older children and adults with varying degrees of binocular diplopia or abrupt esotropia. The majority of adult patients experienced diplopia solely when looking at the distance. Adult AACE patients are mostly myopic, whereas all hyperopia patients are adolescents. The angle of esotropia in the adolescent group was substantially greater than that in the adult group.
According to Mohney30, pediatric AACE patients must be separated from acquired nonaccommodative esotropia (ANAET). The age of onset and angle of deviation are the major characteristics that set pediatric AACE apart from ANAET. ANAET generally affects children between the ages of 1–5 years, and it seems to be infrequently linked to neurological disorders. Li et al. investigated ANAET patients above the age of 8 years, and all patients reported symptoms of diplopia and large-angle esotropia, which were remarkably similar to adolescent AACE patients.31
Similar to previous studies, the younger children in this study had mild to moderate hyperopia and complained of diplopia2,32−34. Few adult patients recalled that the experienced intermittent diplopia, but the condition was concealed until the onset of acute diplopia symptoms. This suggests that the disease course in adults can be described as progressive progression after the disease's onset9,35. However, considering the rapid onset of suppression, some young children can't express symptoms clearly, and it is more difficult for them to obtain subjective reports31.
In this study, 96.6% of adults with AACE were myopic and the rest were emmetropia, similar to Spierer et al22, which was significantly different from the adolescents group. Patients' ages were found to be negatively correlated with SE-Right or SE-Left, implying that the older they get, the more myopic they become.
As previous studies9,22,36, the esotropia angles of AACE patients can be the same when looking at near and far distances, the difference is less than 5 prisms. This characteristic also helps to distinguish AACE from the disorder of divergent malfunction37. Divergent dysfunction can also cause rapid esotropia, however, this illness is characterized by ocular ductions and concurrent esotropia exclusively at distance, while the patient is orthophoric at near fixation. Furthermore, we discovered that the adolescent group's esotropia angles were much higher than those of the adult group. While the angle of esotropia and age had a strong negative connection.
Most strabismus patients are unable to establish normal stereoscopic function because of abnormal retinal correspondence caused by axial deviation. No statistically significant difference was found between the two groups in our investigation regarding binocular visual function. Most AACE patients are older children and adults, and most of them have complete binocular visual functions before the onset of AACE. Although the incorrect ocular position will affect stereo vision, timely intervention is helpful to reconstruct binocular vision4,34. Several researchers believe that the time between the onset of esotropia and the start of treatment is not the key factor to restore normal stereoscopic vision. However, all patients eventually regained high stereovision despite a complicated process and chronic lack of stereopsis.
There may be some possible limitations in this study. This study compared the differences in the disease's natural course in AACE patients of various ages. To comprehend the characteristics of the AACE and the effects of its treatment, more research is required. The patients will then be followed up over time for a more in-depth study.