Abstract
Purpose:
To identify factors associated with late decompensation of horizontal strabismus after prolonged (>12 months) postoperative stability.
Methods:
A retrospective chart review of all pediatric (<18 years) surgical strabismus cases performed from 1999 to 2009 by one surgeon in a tertiary referral center was performed. Group 1 included patients with good postoperative horizontal alignment (<10 PD) who remained stable during the follow up period (minimum 24 months). Group 2 included patients with initially good postoperative alignment who experienced decompensation (≥ 10 PD on 2 visits) more than 12 months after surgery. Analyzed variables included: initial deviation size; presence of oblique dysfunction, amblyopia, and DVD; age at time of surgery; postoperative stereoacuity; refractive error; Medicaid status; deviation size at the first >12 months visit; and change in deviation direction between visits.
Results:
Of 529 cases reviewed, 185 met inclusion criteria. Age range was 0.5 to 15.5 years. Group 1 contained 128 cases with a mean follow-up of 58 months. Group 2 contained 57 cases with a mean follow-up of 72 months. Overall, the late decompensation rate was 31%. Of these, 31 patients underwent reoperation (54%). Oblique dysfunction on the first preoperative visit was significantly higher in group 2 (24 vs. 12%, P=0.04, OR=2.33, CI=1.02-5.31). Any measurable postoperative stereoacuity on visit 3 (mean = 3.5y post-op) was significantly higher in group 1 (67 vs. 37%, P=0.01, OR=3.40, CI=1.32-8.77). Distance deviation size ≥ 4-8 PD on the first >12 months postoperative visit was significantly associated with late decompensation compared to deviation of <4 PD (OR= 2.2, CI=1.07-4.52).
Conclusions:
Oblique dysfunction is negatively associated with long-term stability, possibly because it is a surrogate for sensory torsion and poor fusion. Persistent lack of measurable postoperative stereoacuity should prompt close monitoring of patients for decompensation. Deviation size at one year following surgery is an indicator for the duration of stable alignment and for the probability of later decompensation. Patients with <4 PD horizontal tropia at that time are less likely to decompensate and more likely to remain stable for a longer period of time. Our data suggest that within the monofixation range, postoperative alignment of 0 - 4 PD is significantly more likely to be associated with stability than alignment of 4 - 8 PD.
Keywords: 725 strabismus: treatment