Undercorrection of symptomatic esophoria after unilateral medial recession

Symptomatic esophoria (SE) is a latent esodeviation that progresses into a manifest esotropia. Symptoms may include diplopia, headaches, and asthenopia. One muscle surgery is controversial due to concerns about undercorrections and/or the development of horizontal gaze incomitance. The aim of this retrospective observational study was to compare undercorrection rates in SE patients receiving standard orthoptic evaluation versus those supplemented with a prism adaptation test (PAT).

We reviewed records of patients with SE who underwent unilateral medial recession (UMRc) surgery at the Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark, from 1 January 2017, to 31 August 2023. We collected information on whether PAT was conducted, demographics, and medical and ophthalmological history. Primary outcome was undercorrection after unilateral medial recession. Secondary outcomes included amount of lateral incomitance and changes in the angle of deviation following PAT.

Forty-one SE patients were included, with 29 in the non-PAT group and 12 in the PAT group. After adjusting for baseline deviation, the mean difference in deviation at near (AODn) and distance (AODd) was lower in the PAT group compared to the non-PAT group, respectively (p = .4 and p = .02). Mean adjusted AODd difference in ipsilateral and contralateral gaze to the side of UMRc was also lower in the PAT group compared to the non-PAT group, respectively (p < .001 and p = .009).

SE patients who underwent PAT had lower residual deviation and were less prone to ipsilateral gaze incomitance on the side of the UMRc, compared with those who did not undergo PAT.