[Study on the difference of binocular accommodative response between atients with intermittent exotropia under...

Area of Science:

• Ophthalmology
• Vision Science
• Neuroscience

Background:

• Intermittent exotropia (IXT) is a common strabismus characterized by outward deviation of the eyes.
• Understanding the accommodative response in IXT is crucial for managing binocular vision and visual development.
• Objective evaluation of accommodation can reveal subtle deficits or alterations in IXT patients.

Purpose of the Study:

• To objectively assess the accommodative response in patients with intermittent exotropia (IXT).
• To investigate alterations in accommodative response when IXT patients maintain binocular fusion.
• To compare accommodative responses between IXT patients and healthy controls.

Main Methods:

• A prospective cohort study included 24 patients with basic IXT and 24 healthy controls (ages 10-27).
• Accommodative response was measured using an open-field autorefractor (WAM-5500) under binocular and monocular viewing at 5m and 40cm.
• Participants wore full correction spectacles to ensure best-corrected visual acuity.

Main Results:

• Under near fixation (40cm) binocular viewing, accommodative response was asymmetric between fixating and deviating eyes in the IXT group (P<0.001).
• The asymmetric accommodative response during binocular viewing was significantly greater in the IXT group compared to controls (P<0.001).
• Near fixation monocular viewing showed significant differences in accommodative response between fixating and deviating eyes in the IXT group (P=0.003).

Conclusions:

• Patients with IXT exhibit asymmetric accommodative responses, with a tendency for decreased response in the deviating eye under near binocular viewing.
• The change in accommodative response during binocular fusion is more significant in IXT patients than in normal controls.
• These findings highlight potential underlying mechanisms affecting binocular vision and accommodation in IXT.