The changes of retinal nerve fibre layer and ganglion cell layer with different severity of thyroid eye disease

To evaluate the changes of retinal nerve fibre layer (RNFL) and ganglion cell layer/inner plexiform layer (GCL/IPL) with the severity of thyroid eye disease (TED).

One hundred and forty-five eyes of 75 patients with TED and 70 eyes of 35 healthy controls were included. The eyes with TED were divided into mild group (35 eyes), moderate-to-severe group (42 eyes) and DON group (68 eyes). The thickness of RNFL and GCL/IPL were measured by optic coherence tomography (OCT). Clinical activity score (CAS), best corrected visual acuity (BCVA), intraocular pressure (IOP), proptosis and mean deviation (MD) by Humphrey perimetry were assessed.

The CAS had significant difference between the three groups (p < 0.001). The proptosis and IOP were significantly higher in DON group and moderate-to-severe group than mild group (p < 0.05). The MD and BCVA were significantly worse in DON group compared with mild group and moderate-to-severe group (p < 0.001). The mean GCL/IPL thickness was thinnest in DON group (p < 0.001). The mean RNFL thickness had significant difference between moderate-to-severe group and DON group (p = 0.036). The mean GCL/IPL thickness had a significant correlation with MD (r = 0.449, p < 0.001) and VA (r = -0.388, p < 0.001), whereas the mean RNFL thickness had no significant correlation with MD (p = 0.082) or VA (p = 0.226).

Subclinical optic neuropathy might progress in the patients with moderate-to-severe TED. OCT measurements of GCL/IPL and RNFL are useful to detect the early changes of optic nerve. The thinning of GCL/IPL might be a strong suggestion for closer vision follow-up and earlier decompression surgery.