Background
Esotropia is a type of strabismus [1] or eye misalignment. [2] The term is derived from 2 Greek words: ésò, meaning inward, and trépò, meaning turn. In esotropia, the eyes are crossed; that is, while one eye looks straight ahead, the other eye is turned in toward the nose. The angle is extremely variable and can exceed 50° with a reduction of exodeviation, even under monocular stimulation. This inward deviation of the eyes can begin as early as infancy, later in childhood, or even into adulthood.
Acquired esotropia can occur after infancy and is not always responsive to farsighted glasses; because of this, it does not fall into the categories of congenital esotropia or accommodative esotropia, which are described in other articles. However, an accommodative component may be associated. [2, 3]
Although acquired esotropia can occur in patients aged 1-8 years, it typically develops in patients aged 2-5 years and appears to be infrequently associated with an underlying disease. [3] With acquired esotropia, the angle of deviation is relatively small, and early surgical correction (when indicated) is more likely to achieve bifoveal fixation for these patients than for those with congenital esotropia.
Pathophysiology
Additional laboratory and clinical research often is required to determine the etiology of the acquired strabismus. [1] Scientists agree that some strabismus cases arise from a primary motor anomaly, while others arise from a primary sensory anomaly. Although different treatment approaches clearly are needed for different conditions, no agreement exists on the details for many conditions.
Epidemiology
Frequency
International
Of those children with esotropia, 10.4% of them are diagnosed with acquired esotropia. [4]
Mortality/Morbidity
Organic pathologies have been diagnosed in patients initially presenting with strabismus. [1] In a recent study, 11.52% of patients with strabismus had posterior segment abnormalities. The most common diagnoses included Toxoplasma chorioretinitis, morning glory anomaly, Toxocara retinopathy, retinopathy of prematurity, and Coats disease. The mean age of onset of the deviation was found to be significantly lower in patients with esotropia. No correlation existed between the degree of visual impairment and the direction of deviation. This fact emphasizes the importance of performing a fundus examination in each patient presenting with strabismus.
Race
No racial predilection exists.
Sex
No sexual predilection exists.
Age
The median age of onset for children with acquired esotropia is 31.4 months (range, 8-63 mo), with a mean initial angle of deviation of 24 prism diopters (PD).
Prognosis
Binocular sensory function is usually severely compromised by even brief periods of abnormal binocular experience during the first year of life.
Patient Education
The prognosis, as well as advantages and disadvantages of the various modes of treatment, should be discussed with the patient's parents and/or the patient, and a plan should be developed based on this dialogue.
