Efficacy of anti-suppression therapy in improving binocular vision in children with small-angle Esotropia

To evaluate the efficacy of anti-suppression exercises in children with small-angle esotropia in achieving binocular vision.

A retrospective review of patients aged 3-8 years who underwent anti-suppression exercises for either monocular or alternate suppression between January 2016 and December 2021 was conducted. Patients with esotropia less than 15 prism diopters (PD) and visual acuity ≥ 6/12 were included. Patients with previous intra-ocular surgery or less than three-month follow-up were excluded. Success was defined as the development of binocular single vision (BSV) for distance, near, or both (measured clinically with either the 4 prism base out test or Worth four dot test) and maintained at two consecutive visits. Qualified success was defined as the presence of diplopia response for both distance and near. Additionally, improvement in near stereo acuity was measured using the Stereo Fly test.

Eighteen patients with a mean age of 5.4 ± 1.38 years (range 3-8 years) at the time of initiation of exercises were included in the study. The male female ratio was 10:8. The mean best corrected visual acuity was 0.18 LogMAR unit(s) and the mean spherical equivalent was +3.8 ± 0.14 diopters (D). The etiology of the esotropia was fully accommodative refractive esotropia (8), microtropia (1), post-operative infantile esotropia (4), partially accommodative esotropia (1), and post-operative partially accommodative esotropia (4). Patients received either office-based, home-based, or both modes of treatment for an average duration of 4.8 months (range 3-8). After therapy, BSV was achieved for either distance or near in 66.6 % of patients (95 % CI = 40.03-93.31 %). Binocular single vision for both distance and near was seen in 50 % of children. Qualified success was observed in 38.46% of patients. Persistence of suppression was observed in one patient (5.5 %). Near stereopsis improved to 200 s of arc or more in 60% of the patients. The mean esotropia reduced from 5.7 ± 4.0 PD for distance and 6.2 ± 4.66 PD for near to 2.7 ± 2.4 PD and 3.38 ± 4.7 PD respectively, at the last follow-up (p-value 0.004 and 0.006). Failure of therapy was noticed after six months of follow-up in the child with infantile esotropia.

Anti-suppression exercises may be beneficial to improve binocular vision functions in children with small-angle esotropias of variable etiologies. Recurrence of suppression after cessation of therapy is possible, warranting regular follow up.