Changes in retinal correspondence following surgery for intermittent exotropia

Area of Science:

• Ophthalmology and Vision Science
• Strabismus Research
• Binocular Vision Studies

Background:

• An intermittent exotrope presented with complex binocular vision characteristics.
• The patient exhibited harmonious anomalous correspondence (HAC) during squinting and normal correspondence (NC) during bifoveal fixation.

Observation:

• Measurements of the angle of deviation (H) and angle of anomaly (A) were taken postoperatively.
• Data were collected over 2.5 months, including a second surgical intervention.

Findings:

• Post-surgery, the patient achieved 3-delta exophoria with NC during fusion.
• Disrupted fusion revealed anomalous correspondence (A = 3-delta exo).
• Changes in the angle of anomaly were not attributable to fusional vergence shifts.

Implications:

• Halldén's sensory-fusion mechanism provides a better explanation for the observed results than fusional vergence changes.
• This suggests a complex interplay between sensory input and motor fusion in maintaining binocular alignment.
• Understanding these mechanisms is crucial for managing strabismus and anomalous correspondence.