Changes in retinal nerve fibre layer, ganglion cell layer and visual function in eyes with thyroid eye disease of different severities with and without orbital decompression

Purpose To evaluate progressive changes in retinal nerve fibre layer (RNFL), ganglion cell layer/inner plexiform layer (GCL/IPL) and visual function in thyroid eye disease (TED) patients with and without orbital decompression. Methods Sixty TED patients (105 eyes) were included. All patients were divided into mild, moderate-to-severe and dysthyroid optic neuropathy (DON) groups. Orbital decompression was performed in the moderate-to-severe and DON groups. Optic coherence tomography (OCT), visual field (VF) and best-corrected visual acuity (BCVA) were performed pre- and postoperatively. Preoperative follow-up was performed in the mild group and in part of the moderate-to-severe and DON groups. Results After decompression, the thickness of GCL/IPL and RNFL significantly decreased in DON group ( p < 0.05), with varying degrees of decrease in eyes with optic disc swelling, atrophy and normal appearance. The mean GCL/IPL thickness significantly decreased in moderate-to-severe group ( p < 0.05), the mean RNFL thickness slightly decreased with no statistical significance ( p = 0.07). During the preoperative follow-ups, the mean GCL/IPL thickness significantly decreased ( p = 0.04), whereas the mean RNFL thickness tended to increase ( p = 0.13) in DON group. The thickness of GCL/IPL and RNFL did not change significantly in the mild and moderate-to-severe groups ( p > 0.05). BCVA and VF did not change significantly in any group ( p > 0.05) preoperatively. Conclusion Swelling and degeneration of retinal ganglion cells (RGCs) may coexist in DON eyes, leading to continuous changes in the RNFL and GCL/IPL thickness either before or after decompression. Slight swelling and degeneration of RGCs may exist in moderate-to-severe TED eyes, although OCT measurements and visual functions remain stable before surgery.