Abstract
Purpose: :
To examine changes in retinal capillary blood flow in relation to changes in retinal nerve fiber layer (RNFL) thickness and optic disc measures in patients with primary open-angle glaucoma (OAG).
Methods: :
Analysis was performed on 72 patients (age 67.9, 41 females) with OAG participating in the Indianapolis Glaucoma Progression Study (IGPS) for changes in retinal capillary blood flow and RNFL and optic disc measures after one year. Confocal scanning laser Doppler flowmetry [Heidelberg Retinal Flowmeter (HRF), Heidelberg Engineering, Heidelberg, Germany] was used to measure perfusion within peripapillary retinal capillary beds. HRF was taken in superior and inferior temporal retinal fields. Heidelberg Retinal Tomograph (HRT) and Optical coherence tomography (Optical Coherence Tomograph (OCT), Zeiss Meditec, Dublin, CA) were used to measure RNFL thickness and measures of optic disc morphology.The change from baseline to one year was calculated for each parameter and Pearson correlation analysis examined the relationship between changes in retinal capillary blood flow in relation to changes in RNFL thickness and optic disc measures. P <0.05 were considered statistically significant.
Results: :
Decreasing retinal capillary blood flow in the superior retina significantly correlated with thinning of the RNFL thickness (superior, r=0.29, p=0.014; inferior r=0.37, p=0.001; and average r=0.44, p=0.000) as measured by OCT. Decreasing retinal capillary blood flow in the superior retina significantly correlated thinning of mean RFNL (r=0.24, p=0.047), decreasing rim area (r=0.23, p=0.05), increasing C/D area ratio (r=-0.26, p=0.03), linear C/D ratio (r=-0.27, p=0.023) and increased cup area (r=-0.24, p=0.05) measured by HRT.
Conclusions: :
In patients with OAG, decreasing retinal capillary blood flow correlates with thinning RNFL, decreasing rim area, increasing C/D ratio and cup area after one year. Patients with lower retinal capillary blood flow may be at higher risk for glaucoma progression.
Keywords: blood supply • retina • clinical (human) or epidemiologic studies: risk factor assessment