Retinal and Choroidal Alterations in Thyroid-Associated Ophthalmopathy: A Systematic Review

Thyroid-associated ophthalmopathy (TAO), or Graves' orbitopathy (GO), is a complex autoimmune disorder affecting orbital tissues, often leading to vision-threatening complications such as dysthyroid optic neuropathy (DON). In this systematic review, conducted following PRISMA guidelines, 22 studies were evaluated to investigate the role of optical coherence tomography (OCT) in assessing retinal and choroidal changes in TAO. Parameters such as the retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), ganglion cell layer (GCL), and choroidal thickness were analyzed. RNFL changes varied by disease severity, with significant thinning in DON due to nerve fiber loss and thickening in early DON due to optic disk edema. Subfoveal choroidal thickness (SFCT) was consistently higher in active TAO, correlating positively with the clinical activity score (CAS) and proptosis, suggesting its role as a marker of disease activity. Subgroup analysis revealed that spectral-domain OCT (SD-OCT) was the most sensitive for detecting retinal changes. The findings highlight the effectiveness of OCT in detecting minor retinal and choroidal alterations in TAO. However, the variability of study designs, as well as the lack of longitudinal data, limits the ability to draw broad conclusions. Further standardized, long-term investigations are required to properly understand OCT's diagnostic and prognostic value in TAO.