Author(s): Kandasamy Sivakumar1, Periasamy Geetha2
Essential Infantile Esotropia (EIE) is the most common type of strabismus. About 0.1% of the newborn are found to have esotropia.1 Though present since birth, it becomes manifest and remains constant around six months of age. The features are large angle constant strabismus, defective Binocular Single Vision (BSV), cross fixation, DVD and latent nystagmus. Most of the patients have mild-to-moderate hyperopia; the amount of deviation is unrelated to the amount and type of refractive error.
MATERIALS AND METHODS
Fifty cases with EIE were included in this prospective study. A thorough ophthalmic and orthoptic evaluation was done in all the patients. For patients more than three years of age, the angle of deviation was measured with prism bar cover test, and for patients less than three years of age, angle of deviation was measured with Hirschberg’s test. Associated features like cross fixation, abduction limitation, Dissociated Vertical Deviation (DVD), nystagmus, amblyopia and Inferior Oblique Overaction (IOOA) were documented. Occlusion therapy was given to amblyopic patients prior to surgery. All these patients underwent surgery and were followed up for a period of six months.
The prevalence of EIE in our centre was 0.33%. Of the fifty patients, 28 were males and 22 were female patients. 39 patients (78%) had deviation of 30-50 Prism Dioptres (PD). Incidence of DVD, inferior oblique overaction and nystagmus was found to be lower when compared to western population. Amblyopia should be diagnosed early and treated adequately before surgery. Standard surgical option is bimedial recession. Monocular recession-resection surgery in one eye can be opted for in cases of irreversible amblyopia. Three or four muscle surgery can be done if deviation is very large. If marked inferior oblique overaction is present, the same should be weakened in addition to the horizontal muscle surgery.
EIE is the most common type of strabismus. These patients have large and constant angle of deviation. Most of them have mild-to-moderate hyperopia. Amblyopia should be diagnosed early and treated promptly before surgery. Patients show limitation of abduction, cross fixation, dissociated vertical deviation, inferior oblique overaction and nystagmus. Early surgery within two years gives best visual outcome in the form of binocular vision and stereopsis.