The reasons behind nonsurgical conversion from esotropia to exotropia are unclear

While conversion from esotropia to nonsurgical exotropia in children is rare, hyperopia is not necessarily the cause of this phenomenon.

Study design

This was a retrospective, multicenter, observational case series involving 49 children aged ≥6 months who were diagnosed with esotropia that subsequently converted to exotropia. There was no history of surgical treatment, including botulinum toxin injections. Patients with vision <20/200 or who had other eye diseases were excluded.

Outcomes

The average time from esotropia to exotropia presentation was approximately 5 years. Exotropia presented at distance in nearly all patients, and 74% of patients also became exotropic at near. There was no significant difference in mean refractive error between the esotropia and exotropia presentations. Only about one-third of patients had high hyperopia; moderate hyperopia was more common.

Limitations

While the authors propose theories as to why esotropia turns into exotropia, the exact mechanism is unknown. In addition, there were 14 patients who had deviations >15 PD, and it is unclear why they did not undergo surgery for their esotropia before it converted. Also, only 49 children were included in this study spanning 40 years and 5 practice sites. This suggests that the number of children who initially present with esotropia and become exotropic without surgery is likely low.

Clinical significance

It is important to follow children with esotropia (both accommodative and non-accommodative) who are not necessarily candidates for surgery, as some of these children may become exotropic over time and ultimately need surgery for the exotropia.

Financial Disclosures: Dr. Brenda Bohnsack discloses no financial relationships.