Analysis of colour defects and microvascular abnormalities in dysthyroid optic neuropathy using optical coherence tomography angiography.

PURPOSE: To evaluate the correlation between colour vision deficiency and microvascular abnormalities in patients with dysthyroid optic neuropathy (DON).

METHODS

Patients with DON and healthy controls were enrolled. HRR colour examination and OCTA device were used for all the subjects. The vessel density (VD), optic disc-associated capillary density (CD), foveal avascular zone (FAZ) area, ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) were compared between the DON and normal groups. In addition, the correlation between the OCTA parameters and the Hardy-Rand-Rittler (HRR) score was also assessed.

RESULTS

One hundred and fourteen eyes of 60 patients (30 patients with DON and 30 normal controls) were included in our study. The HRR score, RNFL, FAZ and parafoveal vessel density were lower in DON patients than in healthy controls (p < 0.05). We detected significant correlations between the HRR score and the radial capillary density (RPC), superficial capillary plexus (SCP), deep capillary plexus (DCP) and RNFL. The HRR test plays an important role in the diagnosis of DON. Protan deficiency was the major type of colour deficiency in DON according to the HRR test.

CONCLUSION

In terms of pathogenesis, colour vision defects may be correlated with changes in retinal blood flow in patients with DON, which could be early signs for the diagnosis of DON.