Korean researchers discovered that interocular thickness differences in the central foveal, retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layers (GC-IPL) significantly increased as diabetic retinopathy (DR) severity increased. They note that these findings may be indicative of DR progression.

The team evaluated the foveal, RNFL and GC-IPL thicknesses of 508 eyes from 254 patients with different severities of DR and 184 eyes from 92 healthy control subjects using spectral-domain optical coherence tomography.

They found that the interocular differences in the average GC-IPL thicknesses of the severe nonproliferative DR (NPDR) and proliferative DR groups were significantly larger than those of the control group. They note, however, that there was no significant difference in thickness between the control and mild to moderate NPDR groups. The team adds that in the group with proliferative DR, the interocular difference in the average GC-IPL thickness was greater than that of the foveal and RNFL thicknesses.

The study concludes, “the DR severity and the interocular difference in central foveal thickness were significantly correlated with the interocular difference in the average GC-IPL thickness.”

Lim HB, Lee WH, Jo YJ, et al. Interocular asymmetry of the ganglion cell-inner plexiform layer in diabetic retinopathy. Optom Vis Sci. 2018;95(7):594-601.