Age-Related Changes in Ocular Blood Velocity in Suspects with Glaucomatous Optic Disc Appearance. Comparison with Healthy Subjects and Glaucoma Patients

Abstract

PurposeTo evaluate retrobulbar blood flow characteristics of glaucoma suspects with glaucomatous optic disc appearance (GODA) in comparison to healthy control group (CG) and primary open angle glaucoma patients (POAG) and assess the effect of age.Methods145 patients from a single glaucoma clinic were enrolled and classified into two diagnostic groups (GODA and POAG). Third group of subjects consisted of 67 age matched individuals (CG). Retrobulbar blood velocity measurement in central retinal artery was performed using color Doppler imaging (CDI). CDI images were processed in custom software leading a range of parameter estimates from a continuous waveform signal. The effect of age on the estimated parameters was evaluated with the stepwise forward regression and ANCOVA in which age was used as a continuous factor. One-way ANOVA was used to test for the differences in the CDI parameters between the three considered groups. Correlation between restive index (RI) and pulsatility index (PI) was assessed with a bilinear fitting guaranteeing no discontinuities in RI intercept estimate. Fisher test was used to assess the applicability of a bilinear PI/RI relationship, while the statistics of the RI intercept estimate were evaluated using the bootstrap.ResultsANCOVA showed significant interaction between age and group (p<0.05) for five out of nine considered CDI parameters. The RI intercept for CG and GODA groups was 0.602±0.047, and 0.574±0.044 respectively, while the RI intercept of 0.934±0.066 was found for the POAG.ConclusionsThe observed similarity of CG and GODA group and dissimilarity between GODA and POAG groups in terms of PI/RI relationship is remarkable. Age may play some role in the different mechanisms occurring in blood velocity dynamics in GODA and POAG subjects but it is not a strongly determining factor.

Peripapillary Retinal Nerve Fiber Layer Vascular Microcirculation in Glaucoma Using Optical Coherence Tomography–Based Microangiography

“…The reason for that needs further investigation, but previous studies have also detected abnormalities in blood flow in glaucoma suspects. Asejczyk-Widlicka et al 32 used color Doppler imaging (CDI) to show a significant decrease in end diastolic velocity in the central retina artery in a glaucoma suspect group that had normal mean RNFL thickness compared with age-matched normal controls. Piltz-Seymour et al 33 found significantly diminished flow in POAG suspect eyes before the development of clinically detectable visual field loss using Laser Doppler flowmetry (LDF).…”

Randomized controlled trial of electro‐stimulation therapies to modulate retinal blood flow and visual function in retinitis pigmentosa

“…We used the reciprocal of the changes in MFV for the RBF measures and mfERG ratios, as indicated by Box-Cox analysis to obtain a normal distribution for those variables. Changes from mean baseline for CRA blood flow (i.e., PSV, EDV and MFV) or RBF (i.e., MFV) in the TES or electro-acupuncture groups compared to sham controls at each follow-up visit were adjusted for age (Asejczyk-Widlicka et al 2015) and gender, (Yanagida et al 2015) and analyzed using multilevel linear regression models (i.e., random-effects maximum likelihood estimation) to account for correlations between a subject’s eyes (with data from both eyes included), and p<0.05 was defined as statistically significant, using Stata/IC version 13.1 (Stata Corp., College Station, TX). This was an exploratory trial that was not specifically planned to be powered with an adequate sample size to demonstrate significant changes in blood flow or visual function; therefore, it was not appropriate to adjust for multiple comparisons (e.g., Bonferroni).…”

Reduced Central Retinal Artery Blood Flow Is Related to Impaired Central Visual Function in Retinitis Pigmentosa Patients

“…20 In young, healthy normals, a slight but significant increase in CRA blood flow occurred among those with greater MAP, 21 which was not found in our RP data (−0.02; 95% CI: −0.06, 0.01; p = 0.19); therefore, we did not adjust for MAP in our analyses. MFV and EDV were both normally-distributed variables as per Shapiro–Wilk analysis; however, PSV was not normally-distributed, and therefore, we performed a log-transformation of this variable to use for the analysis.…”