Binocular status after surgery for constant and intermittent exotropia

Area of Science:

• Ophthalmology
• Strabismus Surgery
• Binocular Vision

Background:

• Intermittent exotropia (X(T)) is a common form of strabismus.
• Constant exotropia can develop from decompensated intermittent exotropia.
• Understanding sensory outcomes in different exotropia types is crucial for surgical planning.

Purpose of the Study:

• To compare postoperative bifixation and sensory outcomes in patients with constant exotropia (with and without prior X(T)) versus those with X(T).
• To determine if prior X(T) influences sensory recovery in constant exotropia patients.

Main Methods:

• Prospective comparative clinical study involving 63 patients with intermittent or constant exotropia.
• Patients were divided into three groups: X(T), constant exotropia with prior X(T), and constant exotropia without prior X(T).
• Surgical outcomes assessed motor alignment (within 8 PD) and sensory outcomes (bifixation and gross stereopsis).

Main Results:

• Motor alignment rates were similar across groups (79% X(T), 71% constant with prior X(T), 67% constant without prior X(T)).
• Bifixation was achieved by 74% of X(T) patients, but none in the other two groups.
• Gross stereopsis was achieved by 100% of X(T) patients, 79% with prior X(T), and 33% without prior X(T).

Conclusions:

• Constant exotropia patients with prior X(T) show better gross stereopsis than those without, but worse bifixation and gross stereopsis than X(T) patients.
• Decompensated constant exotropia from X(T) may indicate a missed opportunity for optimal treatment timing.
• Surgical intervention for exotropia should consider the patient's history for predicting sensory outcomes.