Abstract
Purpose :
To quantify the short-term effects of IOP elevation on macular and peripapillary OCTA vessel density in normal human eyes.
Methods :
6mm macula and 4.5mm ONH OCTA (AngioScan®, NIDEK RS-3000 Advance 2) and tonopen IOPs were performed on one eye in 8 healthy adults. A scleral suction cup (taberna pro medicum GmbH) was then used to increase IOP to targets of 15, 22.5, and 30mmHg above baseline (BL), with 5min rest between rounds. For each round of IOP increase, OCTA scans were taken at 3min of suction. Final OCTA and IOPs were performed 5min after last suction removal. Change from BL was analyzed using paired 2-tailed ttests for the following: AngioScan® macular superficial and deep vessel densities (sVD, dVD) in ETDRS sectors and a 9 square grid; and radial peripapillary capillary vessel densities (rVD) in 8 sectors.
Results :
Mean age (mean±SD) was 26.3±3yr. 4 subjects were female. 5 eyes were OD. BL IOP was 15.8±2.8mmHg. Real IOP increase from BL (mean Δ±SD) for each round of elevation was 15.8±3.9, 22.7±2.8, and 28.6±4.5mmHg. Final IOP was 6.5±2.8mmHg.
All ETDRS sVD sectors increased at final compared to BL and was significant centrally (mean Δ 1.125±1.053mm-1, p=.03). sVD nonsignificantly decreased in 7 of 9 ETDRS sectors at 30mmHg. sVD nonsignificantly decreased at 30mmHg and increased at final for ETDRS whole, inner, and outer rings (30mmHg -0.500±2.450, -0.125±2.260, -0.750±2.385mm-1; final 0.625±1.495, 1.000±1.414, 0.375±1.111mm-1). Grid sVD showed no significant changes, but decreased in all 9 squares at 30mmHg and increased in 8 of 9 at final.
dVD nonsignificantly decreased in all 9 grid squares and all 9 ETDRS sectors for all IOP elevations.
rVD significantly decreased at 15mmHg in the superior hemifield (-2.000±1.414mm-1, p=.007), and 30mmHg both superior and inferior (-2.500±2.398, p=.03; -2.125±2.713mm-1, p=.03). rVD significantly decreased at 15mmHg in the superior nasal (-2.250±2.437mm-1, p=0.04), nasal superior (-3.000±2.739mm-1, p=0.02), and temporal superior (-1.500±1.225mm-1, p=0.03) sectors; and at 30mmHg in the superior nasal (-3.125±2.934mm-1, p=0.03) and nasal superior (-3.125±2.634mm-1, p=0.03) sectors.
Conclusions :
Transient IOP elevation generally decreased OCTA macular sVD at 30mmHg elevation and significantly increased sVD at final compared to BL. dVD generally decreased at all rounds of IOP elevation. rVD decreased with 15 and 30mmHg IOP elevation especially superiorly.
This is a 2020 ARVO Annual Meeting abstract.