Abstract
Purpose :
The pattern of peripapillary retinal nerve fiber layer (pRNFL) loss in eyes with temporal hemianopia and band atrophy (BA) of the optic nerve from chiasmal compression is an important model to evaluate new methods of quantifying axonal loss in anterior visual pathway diseases. This cross-sectional study compares circumpapillary vessel density (cpVD) using optical coherence tomography angiography (OCTA) in patients with BA and controls and look into the relationship between cpVD, pRNFL and visual field (VF) loss.
Methods :
Thirty eyes with BA and temporal hemianopia from chiasmal compression and 30 healthy control eyes underwent OCTA (DRI OCT Triton Plus, Topcon, Japan) and VF testing. OCTA scans provided microvasculature information in slabs estimated from the inner limiting membrane to the interface of ganglion cell layer/inner plexiform layer. cpVD was calculated as the percentage area occupied by blood vessels in 4 sectors (Figure) and pRNFL was determined in quadrants. VF loss was evaluated by the mean deviation (MD) and the average VF defect in the temporal hemifield (TMD).
Results :
Reduced cpVD was found in eyes with BA compared to controls (P < 0.01 for all comparisons). In BA eyes, cpVD (SD) in the temporal, nasal, superior and inferior sectors around the disc were 21.3% (5.3), 19.7% (4.3), 44.6% (7.1), and 45.0% (8.2), respectively. In controls, the corresponding values were 37.7% (7.5), 27.5% (5.5), 50.1% (6.3), 53.4% (5.9), respectively. Average (SD) measurement was 32.7% (4.8) in study eyes and 44.2% (4.0) in controls. Compared to controls, all pRNFL thickness measurements in BA eyes were also significantly reduced (P< 0.01).
Significant Spearman correlations were found between the MD and the TMD and the cpVD measurements (range 0.58 to 0.69) and between the cpVD and the pRNFL thickness values (range 0.57 to 0.81), most importantly in the temporal, nasal and average values.
Conclusions :
Compared to controls, BA eyes demonstrated a reduced peripapillary microvascular network that was significantly correlated to the severity of VF damage and with structural RNFL loss. OCTA is a promising technology that can help assessing retinal peripapillary axonal loss in patients with chiasmal compression.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.