Abstract
Purpose: :
To evaluate: (1) the difference in total retinal blood flow between glaucomatous eyes and normal eyes using Doppler spectral-domain optical coherence tomography (Doppler OCT) and (2) the correlation between retinal blood flow and other measures of glaucoma severity.
Methods: :
Eight eyes of seven glaucoma subjects and nine eyes of nine control subjects were evaluated by multiple modalities including Doppler OCT (Optovue RTVue SD-OCT), OCT for retinal nerve fiber layer thickness (Zeiss Stratus OCT), confocal laser ophthalmoscopy (Heidelberg Retinal Tomography), scanning laser polarimetry (Zeiss GDx), and conventional static perimetry (Zeiss Humphrey 750i Visual Field Analyzer). Doppler OCT was performed using previously described dual circular scanning protocols. The semi-automated Doppler OCT Reading Center (DOCTORC) software was used by certified reading center graders to verify and refine vessel positions and calculate blood flow velocities from all arteries and veins near the optic nerve head. Retinal blood flow measurements were correlated with measurements from other diagnostic modalities used to diagnose and monitor patients with glaucoma.
Results: :
Total retinal blood flow was significantly decreased in glaucoma eyes (36.9 microliters/min) compared to control eyes (49.5 microliters/min) (p=0.001). Arterial cross-sectional area was significantly reduced and venous velocity demonstrated a trend toward reduction (p=0.06). Arterial velocity and venous cross-sectional area remained stable. The decrease in retinal blood flow was significantly correlated with the severity of glaucoma as measured by static perimetry (mean deviation and pattern standard deviation), OCT retinal nerve fiber layer analysis, confocal laser ophthalmoscopy, and scanning laser polarimetry (p=0.01).
Conclusions: :
Retinal blood flow as measured by Doppler OCT is significantly reduced in eyes with glaucoma and the degree of reduction is correlated with disease severity. Retinal blood flow may be a useful metric in the diagnosis and management of glaucoma and further studies are warranted.
Keywords: blood supply • imaging/image analysis: clinical • optic nerve