Common Forms of Adult Esotropia Require Augmented Surgical Dosing.

Introduction: Age-related distance esotropia (ARDE) in older adults is commonly caused by sagging eye syndrome. Decompensated esophoria (DE) is a progressive esotropia in younger adults. We evaluated claims that dosing of medial rectus (MR) recession must appreciably exceed customary recommendations to avert surgical undercorrections in treatment of DE and ARDE.

Study Design: Comparative interventional case series.

Methods: We compared with Parks' tables the actual dosing of strabismus surgery that included bilateral MR recession in consecutive patients with DE and ARDE from 2015 to 2024.

Results: Strabismus surgery was performed in 54 DE patients of mean age 31 ± 12 years (standard deviation) and 61 ARDE patients of age 70 ± 8 years. Preoperative esotropia was significantly greater in DE at 21 ± 10Δ than 14 ± 9Δ in ARDE (P = .0003). Although surgery initially produced orthotropia in most patients in both groups, esotropia gradually recurred in 10 DE patients (22%) after a mean of 3 ± 1.3 years, due to greater decline in surgical effect than in ARDE (P = .0022). There was no correlation between the use of adjustable sutures and reoperation (P = .73). Regression analysis indicated that the initial 4.6 mm MR recession in DE and 3.5 mm in ARDE had no effect on final alignment, but each additional mm total MR recession corrected 3Δ in DE and 2.4Δ in ARDE. These surgical effects are less than predicted by Parks tables.

Conclusions: Current recommendations for augmented MR recession in ARDE are appropriate, but dosing must be further augmented to achieve satisfactory alignment in DE to avoid undercorrections caused by early recurrences of esotropia.