Comparison of sensory outcomes in patients with monofixation versus bifoveal fusion after surgery for intermittent exotropia.
BACKGROUND
The predictive value of preoperative stereopsis on the surgical outcome of patients with intermittent exotropia is unknown. We hypothesize that it may predict motor and sensory outcome. We report our experience with fusional status at near measured using Titmus circles before and after eye muscle surgery for intermittent exotropia.


METHODS
In this retrospective case series, 95 children underwent bilateral lateral rectus muscle recession. Visual acuity, near stereoacuity, and ocular alignment were measured before surgery and 2 months postoperatively.


RESULTS
Testing variability by use of Titmus circles was examined. A change of greater than 3 stereo circles was found to be substantial (90% confidence interval). Of the 42 children with poor-to-nondetectable stereopsis preoperatively (400 arcsec or worse), 3 improved substantially (140, 140, 60 arcsec). The remaining 53 had moderate- (200 arcsec) to high-grade (60 arcsec or better) stereopsis preoperatively. The majority of children had no change in stereopsis after surgery. Only 4 children had improved stereopsis after surgery; 6 lost stereopsis, of whom 4 had persistent small-angle esodeviations, whereas 1 child had a large overcorrection requiring additional surgery. All children who maintained or improved their stereopsis postoperatively were orthotropic or had persistent exodeviation after surgery. No child with high-grade stereopsis at 2 consecutive preoperative visits lost stereoacuity after surgery.


CONCLUSIONS
A persistent small-angle esotropia at the 2-month postoperative visit is associated with a loss of near stereopsis (p=0.0001) and may occur more frequently in children with subnormal stereopsis preoperatively than in patients with bifoveal fixation. Prism or reoperation may be necessary to treat this complication.
Departments of Ophthalmology and Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. david.morrison.1@vanderbilt.edu
David
D
Morrison
William
W
McSwain
Sean
S
Donahue
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003867:Depth Perception / Q000502:physiology*; D005099:Exotropia / Q000503:physiopathology* / Q000601:surgery*; D005403:Fixation, Ocular / Q000502:physiology*; D005584:Fovea Centralis / Q000502:physiology; D006801:Humans; D013508:Ophthalmologic Surgical Procedures; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D011237:Predictive Value of Tests; D011300:Preoperative Care; D020127:Recovery of Function / Q000502:physiology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology