Management of Patients with Thyroid-Associated Ophthalmopathy: Role of Spectral Domain Optical Coherence Tomography

Abstract

AIM: To demonstrate the changes in optic nerve head (ONH), retinal nerve fiber layer (RNFL) and macula in patients with thyroid-associated ophthalmopathy (TAO) by spectral domain optical coherence tomography (SD-OCT). 
 METHODS: We included forty-one eyes of 41 patients with a diagnosis of TAO and forty-eight eyes of 48 age- and sex-matched healthy subjects (control group) from June 2016 to July 2018. The ONH parameters, RNFL and macular thicknesses in the nine macular quadrants according to ETDRS were measured with SD-OCT. Proptosis level was determined by Hertel exophthalmometer. Clinical activity score (CAS) according to the European Group of Graves' Orbitopathy (EUGOGO) guidelines was determined in all patients. 
 RESULTS: Superior, inferior and average RNFL thicknesses were significantly lower in the TAO group compared to the control group (p < 0.05). Optic disc area was significantly larger in the TAO group. Outer quadrant macular thicknesses and average macular thickness were significantly lower in the TAO group (p < 0.05). CAS had a weak correlation with RNFL thickness and average macular thickness. 
 CONCLUSION: Alterations in RNFL thicknesses and macular thicknesses according to ETDRS template can be detected before the development of ocular symptoms in patients with TAO. OCT is a convenient, non-invasive tool for the evaluation and follow-up of macular structural changes. Patients can be diagnosed at an early stage prior to the development of functional damage. However, the low number of studies investigating this subject and the conflicting findings of existing studies necessitate further studies.