Ultrasonographic motion analysis of lower eyelid compartments in patients with chronic thyroid associated ophthalmopathy

Purpose To present the qualitative and quantitative ultrasonographic findings of lower eyelid compartments in patients with chronic thyroid associated ophthalmopathy (TAO) compared to normal subjects. Methods In a prospective study, dynamic and static ultrasonographic investigation, applying high resolution (15 MHz) ultrasound was performed to assess the lower eyelid, in 15 TAO patients that were in chronic phase and 10 normal subjects. The thickness and echogenisity of dermis, orbicular oculi muscle, lower eyelid retractor muscle, lower eyelid fat pads, and their qualitative relationships during vertical excursion of the globe were evaluated in static and dynamic investigation. Correlation of ultrasonic and clinical findings was evaluated. Results The mean age of the patients was 41.82 ± 7.4 years, and the controls were age-matched (mean age, 42.8 ± 5.6 years). Mean proptosis of the involved eyes was 3.3 mm, and mean lower lid retraction was 2.4 mm in chronic TAO group. Pattern of fat motion was blocky in chronic TAO patients compared to normal jelly motion of the fat in normal cases. In analyzing the range of motion, the difference was significant in the motion of both superficial and deep fat pockets between the two groups (P < 0.001). Limitation of fat motion correlated both with proptosis and lower eyelid retraction (Pearson correlation coefficient = -0.77 vs -0.43, P < 0.001). Fibrotic changes of lower lid fat pads appear in the tissue around the septum on observation. Considering the ultrasound findings, a new staging method is proposed in this study that starts with the appearance of echodense points, getting worse in fine bands, progresses to thick bands and ends in cord formation in the lower lid fat pocket that determines total fibrosis. Conclusion Development of a series of static and dynamic changes in ultrasound is related to the clinical findings in chronic phase of TAO. The limitation of motion and fibrotic changes of lower eyelid fat pads were more detectable in cases with a more severe proptosis and lower lid retraction. It is considered that ultrasound findings can be a representative of the severity of involvement in the chronic phase of the TAO.