Subclinical Ocular Motility Dysfunction and Extraocular Muscle Changes in Inactive Graves' Orbitopathy.

Area of Science:

• Ophthalmology
• Endocrinology
• Medical Imaging

Background:

• Graves' orbitopathy (GO) can cause structural and functional changes in extraocular muscles (EMs).
• Assessing these changes in inactive GO is crucial for understanding disease progression and management.
• Subclinical EOM dysfunction may persist even when GO is clinically inactive.

Purpose of the Study:

• To investigate structural and functional changes in EMs in patients with inactive Graves' disease (GD) and GO.
• To evaluate the efficacy of the Red Filter Test (RFT) in detecting latent diplopia and subclinical EOM dysfunction.
• To correlate EOM changes with clinical parameters in inactive GO.

Main Methods:

• Sixty-seven patients with inactive GO underwent clinical assessments, thyroid function tests, and autoantibody level measurements.
• Orbital ultrasound (US) was used to evaluate EOM morphology.
• Ocular motility was assessed, and patients were stratified based on RFT results (positive for latent diplopia or negative).

Main Results:

• Nearly half of patients (49.25%) with inactive GO showed latent diplopia on the RFT, undetected by standard tests.
• Significant differences were found between RFT-positive and RFT-negative groups in age, disease duration, IOP elevation in up-gaze, and medial rectus muscle thickness.
• No significant differences were observed in thyroid status, autoantibody levels, CAS, exophthalmos, or lateral rectus thickness.

Conclusions:

• Subclinical extraocular muscle dysfunction and morphological changes are present in inactive Graves' orbitopathy.
• The Red Filter Test is a valuable tool for detecting latent diplopia and identifying subtle ocular motility issues.
• Integrated assessments combining functional tests (RFT) and imaging are vital for early GO abnormality detection and management.