Purpose: The goal of this study is to determine the functional and dynamic effects of hyaluronic acid (HA) gel injection into the levator plane for improving upper eyelid retraction in patients with thyroid eye disease (TED).
Methods: This is a prospective, non-randomized study of consecutive patients with symptomatic unilateral upper eyelid retraction in the setting of active and inactive TED. Study participants underwent HA gel injection subconjunctivally into the levator plane and were examined before injection, 1 to 3 months after injection, and at the clinician's discretion thereafter. At each of the time points, high-resolution ultrasound imaging and clinical photographs were taken, and the marginal reflex distance 1 (MRD1) was measured.
Results: Eight patients (4 in the active stage of TED, 4 in the inactive stage of TED) were injected on average with 0.45 ml of HA gel. The average baseline MRD1 was 5.6 mm prior to HA injection, 4.6 mm at the first follow up after injection, and 5 mm at the final follow up after injection. HA was localized ultrasonographically to multiple anatomical locations and changed in morphology over time but not in anatomical location. All patients demonstrated increased fluidity of eyelid excursion on dynamic ultrasound after HA injection. There were no vision-threatening complications in this study.
Conclusions: Despite variability in the HA gel distribution and long-term conformational changes on ultrasound examination, HA injection may be an effective and minimally invasive method to improve upper eyelid position for patients with mild eyelid retraction in both the active and inactive stages of TED.