Quantitative Analysis of Eyeball Rotation During Lateral Gaze in Intermittent Exotropia: A Magnetic Resonance Imaging...

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Intermittent exotropia (IXT) is a common form of strabismus characterized by outward deviation of the eyes.
• Understanding the precise mechanics of eye movement in IXT is crucial for effective management and surgical planning.

Purpose of the Study:

• To quantitatively evaluate eyeball rotation during lateral gaze in patients diagnosed with intermittent exotropia (IXT).
• To utilize three-dimensional magnetic resonance imaging (MRI) for precise measurement of ocular motility in IXT patients.

Main Methods:

• A prospective observational study involving 29 patients with IXT who underwent orbital MRI during central, right, and left gazes.
• Eye rotation angles were measured using ImageJ by comparing optical axes in central versus lateral gazes (40° fixation angle).
• A difference of 3° or more in rotational angle between the two eyes was considered significant.

Main Results:

• Significant differences in rotational angles between eyes during lateral gaze were observed in approximately half of the IXT patients.
• Specifically, 26.7% of patients exhibited a larger adduction angle in one eye compared to the fellow eye's abduction, and 20.0% showed a smaller adduction angle.
• No significant factors were identified that correlated with these observed patterns of eye rotation.

Conclusions:

• The findings suggest that intermittent exotropia (IXT) may not represent a perfectly comitant disturbance of gaze in all affected individuals.
• MRI-based measurement of eye rotation during lateral gaze highlights potential asymmetries in ocular motility within the IXT population.
• These quantitative insights into eye movements are valuable for understanding the physiological mechanisms and refining surgical strategies for IXT.