A new cross-sectional study published in Translational Vision Science & Technology reports that thyroid eye disease (TED) is associated with diffuse, sector-wide corneal stromal thinning — without accompanying epithelial changes or overt topographic abnormalities.
In the retrospective analysis, Chang and colleagues from the National Defense Medical University in Taipei, Taiwan, evaluated 57 eyes from 29 patients with inactive TED and compared them with 18 eyes from nine age- and sex-matched controls. Using spectral-domain OCT (RTVue) for epithelial and pachymetric mapping and dual Scheimpflug imaging (Galilei) for topography, the team assessed total corneal thickness (TCT), corneal epithelial thickness (CET), and corneal stromal thickness (CST) across 25 corneal sectors within a 9-mm diameter map.
While conventional corneal topographic indices – including keratoconus screening parameters – were numerically higher in TED eyes, none reached statistical significance and all remained within normal limits. This suggests that anterior corneal shape remains largely preserved in inactive disease.
In contrast, pachymetric analysis revealed consistent thinning. Mean central TCT was significantly lower in the TED group compared with controls, with similar reductions across most superior, nasal, inferior, and inferotemporal sectors. The temporal sector showed a thinning trend but did not reach statistical significance.
Crucially, the thinning was attributable to the stroma. Central CST measured 480.3 ± 28.8 μm in TED eyes versus 498.9 ± 16.0 μm in controls, with significant reductions observed in nearly all evaluated sectors. By contrast, epithelial thickness did not differ significantly between groups in any region.
Representative pachymetry maps presented in the study illustrated the pattern: TED eyes demonstrate diffuse stromal thinning with preserved sectoral contour, whereas controls exhibit thicker stromal profiles with normal distribution. Importantly, the overall sectoral thickness pattern – thinner centrally and temporally, thicker superiorly – was maintained in both groups, suggesting remodeling rather than focal ectasia.
The findings may help reconcile conflicting reports in the literature regarding central corneal thickness in TED. Previous studies have variably described thickening, thinning, or no change, but this is the first study to isolate stromal thinning as the primary structural alteration.
Although the underlying mechanism remains unclear, the study authors propose autoimmune-mediated extracellular matrix remodeling within the stroma as a possible contributor, warranting further investigation. Because only inactive TED cases were included, whether similar or more pronounced changes occur in active disease remains unknown.
In the retrospective analysis, Chang and colleagues from the National Defense Medical University in Taipei, Taiwan, evaluated 57 eyes from 29 patients with inactive TED and compared them with 18 eyes from nine age- and sex-matched controls. Using spectral-domain OCT (RTVue) for epithelial and pachymetric mapping and dual Scheimpflug imaging (Galilei) for topography, the team assessed total corneal thickness (TCT), corneal epithelial thickness (CET), and corneal stromal thickness (CST) across 25 corneal sectors within a 9-mm diameter map.
While conventional corneal topographic indices – including keratoconus screening parameters – were numerically higher in TED eyes, none reached statistical significance and all remained within normal limits. This suggests that anterior corneal shape remains largely preserved in inactive disease.
In contrast, pachymetric analysis revealed consistent thinning. Mean central TCT was significantly lower in the TED group compared with controls, with similar reductions across most superior, nasal, inferior, and inferotemporal sectors. The temporal sector showed a thinning trend but did not reach statistical significance.
Crucially, the thinning was attributable to the stroma. Central CST measured 480.3 ± 28.8 μm in TED eyes versus 498.9 ± 16.0 μm in controls, with significant reductions observed in nearly all evaluated sectors. By contrast, epithelial thickness did not differ significantly between groups in any region.
Representative pachymetry maps presented in the study illustrated the pattern: TED eyes demonstrate diffuse stromal thinning with preserved sectoral contour, whereas controls exhibit thicker stromal profiles with normal distribution. Importantly, the overall sectoral thickness pattern – thinner centrally and temporally, thicker superiorly – was maintained in both groups, suggesting remodeling rather than focal ectasia.
The findings may help reconcile conflicting reports in the literature regarding central corneal thickness in TED. Previous studies have variably described thickening, thinning, or no change, but this is the first study to isolate stromal thinning as the primary structural alteration.
Although the underlying mechanism remains unclear, the study authors propose autoimmune-mediated extracellular matrix remodeling within the stroma as a possible contributor, warranting further investigation. Because only inactive TED cases were included, whether similar or more pronounced changes occur in active disease remains unknown.
Clinically, the data underscore the importance of layer-specific corneal assessment in TED. Stromal thinning – even in the absence of topographic irregularity – may have implications for refractive surgery planning, IOP interpretation, and the assessment of biomechanical stability in this population.
As imaging technology continues to refine our understanding of corneal microstructure, these findings suggest that TED-related ocular surface changes extend beyond proptosis and exposure, reaching deeper into stromal architecture.
As imaging technology continues to refine our understanding of corneal microstructure, these findings suggest that TED-related ocular surface changes extend beyond proptosis and exposure, reaching deeper into stromal architecture.
