Abstract
Purpose :
To assess differences in ocular hemodynamic and optic coherence tomography angiography (OCT-A) parameters in patients with normal-tension glaucoma (NTG) and healthy controls.
Methods :
11 patients (21 eyes) with NTG (age 71.7(5.2) years) and 21 healthy subjects (42 eyes) (age 70.4(4.5) years) were included in the prospective study. During the study intraocular pressure (IOP), ocular perfusion pressure (OPP), diastolic ocular perfusion pressure (DOPP), and systolic ocular perfusion pressure (SOPP) were assessed. Central foveal thickness (CFT), retinal ganglion cell (RGC) layer thickness and choroidal thickness (ChT) in the foveal region were measured using Swept-source optic coherence tomography (OCT). Superficial foveal avascular zone (FAZ) was evaluated using non-invasive OCT-A. ImageJ program was utilized for FAZ area measurements. Visaul field tests were conducted using the Humphrey 24-2 Swedish interactive thresholding algorithm (SITA) perimeter, mean deviations (MD) were analyzed. The level of significance p<0.05 was considered significant.
Results :
NTG patients had larger superficial FAZ area (3.78(1.2) µm2) and lower RGC layer thickness (11.1(6.3) µm2) than healthy patients (accordingly, 3.33(1.5) µm2 and 13.9(5.9) µm2), however the differences were not significant (p=0.9 and p=0.2). ChT was statistically significantly lower in NTG (169.9(53.7) mm) as compared with healthy patients (211.1(51.7) mm (p<0.01)). DOPP was significantly lower in NTG patients (62.8(7.6) mmHg) as compared to healthy subjects (68.2(8.5) mmHg), p=0.02.
OPP, SOPP and DOPP were related to superficial FAZ area (accordingly, r=-0.59, p=0.004, r=-0.62, p=0.003 and r=-0.43, p=0.049) and RGC layer thickness (accordingly, r=0.57, p=0.008, r=0.64, p=0.002 and r=0.44, p=0.048) in NTG group. Correlations between DOPP and superficial FAZ area (r=-0.36, p=0.03), and between superficial FAZ area and MD (r=-0.41, p=0.01) were found in control group.
Conclusions :
Structural changes of the fovea were related to ocular hemodynamic parameters in NTG patients and further studies are needed to analyze changes in the macular region analyzed by OCT-A in both NTG and high pressure glaucoma patients.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.