Abstract
Purpose :
Visual impairment occurs in some eyes with branch retinal vein occlusion (BRVO). It might be the sequelae of retinal ganglion cells (RGC) death due to regional ischemia in BRVO. We performed a retrospective, observational clinical study to analyze thickness changes in ganglion cell complex (GCC) and optic nerve after BRVO using spectral domain optical coherence tomography.
Methods :
13 eyes of 12 non-glaucomatous BRVO patients were included. Thickness of peripapillary retinal nerve fiber layer (pRNFL), total retina, GCC, inner nuclear layer (INL) and outer retinal layer were measured at baseline and during the clinical course after BRVO (mean follow-up: 13.9±5.8 months). Internal reference ratios (IRR) between BRVO-affected and reference regions were calculated to reflect relative regional thickness changes. Longitudinal and cross-sectional analyses between the affected and reference regions were carried out.
Results :
pRNFL thickness was comparable in the affected and reference sectors at baseline, but then significantly decreased in the affected sector compared to the reference sector (IRR: 1.05±0.23 vs 0.82±0.28, P=0.008). (Fig. 1) Macular was edematous in the affected quadrants at baseline, but total retina thickness returned to the normal range during follow-up with resolution of macular edema. GCC thickness significantly decreased from 142.1±21.2 to 113.8±27.6μm (P=0.002) in the affected quadrants, with a significant decrease in IRR from 1.31±0.13 to 1.06±0.18 (P=0.001). Meanwhile, no significant decrease was observed in INL thickness (54.9±21.0 vs 43.2±16.4μm, P=0.181), which suggests that INL is more resilient than GCC. (Fig. 2) No correlation was found between pRNFL and GCC thickness changes.
Conclusions :
pRNFL and GCC thickness evolved in distinctly different trends after BRVO: pRNFL significantly degenerated in the affected sector; the edematous RGC layer returned to the normal range. These findings suggest anterograde degeneration of RGCs which results in optic neuropathy after BRVO. Thus, pRNFL scans may need to be routinely included in BRVO follow-up, and patients evaluated for clinical signs of optic neuropathy.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.