Response to tocilizumab treatment in Graves' ophthalmopathy by measuring rectus muscle thickness and chemosis using optical coherence tomography.

Purpose: To assess the extraocular muscle thickness and chemosis after treatment with tocilizumab in patients with active Graves' ophthalmopathy by optical coherence tomography.

Methods: Case series of five patients with active Graves' ophthalmopathy (clinical activity score ≥4/10) treated with 4 doses of tocilizumab. These patients had been previously treated with corticosteroids with no response. Spectral-domain optical coherence tomography was employed to determine lateral and medial rectus muscle thickness and chemosis before and after 4 doses of tocilizumab given monthly. Scanning was performed at 3 and 9 o'clock (nasal and temporal).

Results: The study included four women and one man with a median age of 52 years (range: 38-73). Median Graves' ophthalmopathy activity duration was 17 months (12-18). Median medial rectus and determine lateral thicknesses pre-treatment were 249μm (174-366) and 337μm (142-443), respectively. Median chemosis was 409μm (290-610). After tocilizumab treatment, median muscle thicknesses reduced to 157μm (88-187) and 197μm (99-290), respectively (P=.043; Wilcoxon) and chemosis to 59μm (0-78). Median clinical activity score decreased from 5 (4-8) to 1 (0-3).

Conclusions: A reduction in extraocular muscle thickness and chemosis was observed after treatment with tocilizumab in Graves' ophthalmopathy patients using an optical coherence tomography, so this technique could be a useful complementary technique to assess the therapeutic responses.