Bell's phenomenon in thyroid-associated inferior rectus myopathy

Area of Science:

• Ophthalmology
• Endocrinology
• Surgical Research

Background:

• Thyroid-associated ophthalmopathy (TAO) can affect extraocular muscles, particularly the inferior rectus.
• Inferior rectus myopathy in TAO can lead to impaired Bell's phenomenon, impacting corneal protection.
• Surgical intervention is often necessary to address muscle dysfunction in TAO.

Purpose of the Study:

• To evaluate Bell's phenomenon in patients with unilateral thyroid-associated inferior rectus myopathy.
• To assess the impact of inferior rectus muscle recession surgery on Bell's phenomenon.

Main Methods:

• Prospective interventional study involving 12 patients undergoing inferior rectus muscle recession.
• Bell's phenomenon measured before and 3 months post-surgery by assessing upward corneal limbus excursion during forced eyelid closure.
• Statistical analysis included Mann-Whitney U test and paired t-test for comparisons.

Main Results:

• Preoperative Bell's phenomenon was significantly reduced on the affected side (1.6 mm) compared to the unaffected side (4.3 mm).
• Postoperative measurements showed a significant improvement in Bell's phenomenon on the affected side (4.1 mm).
• No significant correlation was found between surgical changes and patient age, recession amount, or deviation angles.

Conclusions:

• Inferior rectus muscle recession surgery effectively improves the diminished Bell's phenomenon in patients with thyroid-associated inferior rectus myopathy.
• The surgical correction helps restore protective eyelid function, reducing the risk of corneal exposure.