Abstract
Purpose:
To compare ganglion cell-inner plexiform layer (GCIP) and circumpapillary retinal nerve fiber layer (cpRNFL) measurements in thyroid associated orbitopathy (TAO) eyes with no, suspected and definite dysthyroid optic neuropathy (DON).
Methods:
Retrospective, cross-sectional study. Thirty-four TAO eyes, including 10 eyes with no DON, 7 with suspected DON and 17 with definite DON were analyzed. All subjects received complete ophthalmic evaluation, visual field (VF) examination with the Humphrey Visual Field Analyzer and optical coherence tomography (OCT) imaging in the macular and circumpapillary regions with Cirrus HD-OCT. Mann-Whitney U tests were used to compare GCIP and cpRNFL thicknesses among the three groups with bootstrap resampling with 10000 replications using one eye from each subject.
Results:
The median GCIP thickness was 83.46 µm for the group with no DON, 81.30 µm for the group with suspected DON, and 78.02 µm for the group with definite DON. Reduced GCIP thickness was observed in the definite DON group (p < 0.017, after Bonferroni adjustments) when compared with the groups with no or suspected DON. The comparison of cpRNFL thickness among different groups showed no significant differences.
Conclusions:
In patients with TAO, GCIP thickness with SD-OCT is a better objective test than cpRNFL for detection of optic neuropathy.