Ocular blood flow in glaucoma – the Leuven Eye Study

Abstract

ABSTRACT.Purpose: Elevated intra-ocular pressure (IOP) has been identified as a major risk factor for glaucoma. Additionally, extensive literature depicts a vascular dysfunction to exist in these patients. However, a large ocular blood floworiented trial to integrate these findings in the clinical setting is lacking. This study would likely help to identify which of these vascular data can be used as a clinical tool for screening and disease stratification. Method: Prospective, cross-sectional, case-control hospital-based study.Patients with primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), ocular hypertension (OHT), glaucoma suspects and healthy volunteers were recruited. In addition to a comprehensive ophthalmological examination, a vascular-oriented questionnaire was completed and ocular blood flow assessment (colour Doppler imaging of retrobulbar vessels, retinal oximetry, dynamic contour tonometry, optical coherent tomography enhanced-depth imaging of the choroid) were performed. Statistical analysis was based on multiple imputation to account for missingness. Results: A total of 614 subjects (291 males) were recruited between March and December 2013 (POAG: 214, NTG: 192; OHT: 27; glaucoma suspect: 41; healthy controls: 140). Glaucoma groups (NTG and POAG) were age and gender matched with the control group (p > 0.05). Glaucoma groups were paired in terms of functional and structural parameters (p > 0.08). Mean ocular perfusion pressure was higher in the glaucoma groups than in controls (p < 0.001). Glaucoma groups had lower retrobulbar velocities, higher retinal venous saturation and choroidal thickness asymmetries when compared to the healthy group, in line with the current literature. Conclusions: The Leuven Eye Study stands as one of the largest clinical trials on ocular blood flow in glaucoma. The creation of this vast database may help integrate the vascular aspects of glaucoma into the clinical practice of glaucoma.

Current Imaging Modalities for assessing Ocular Blood Flow in Glaucoma

“…The results of the study are beyond our scope of discussion. Briefly, they observed that glaucoma groups had lower retro-bulbar velocities and higher retinal venous saturation compared with the healthy group, which was in line with the current literature, 3 essentially implying that vascular parameters could play a moderate role in the pathogenesis of glaucoma.…”

“…Altered retinal and choroidal blood flow, decreased retrobulbar velocities, and higher retinal venous saturation are some factors that have been researched upon and hypothesized to have been involved in glaucoma progression. 3 However, no study integrates all of the above or conclusively provides evidence for vascular dysfunction.…”

Retinal vascular and structural changes are associated with amyloid burden in the elderly: ophthalmic biomarkers of preclinical Alzheimer’s disease

“…The origin of spontaneous RVP in the eye is debated, with some researchers suggesting abnormalities in the ocular perfusion pressure in combination with high central retinal vein pressures as the main factor [33–35], whereas others argue for an imbalance in translaminar pressure gradient across the lamina cribrosa (IOP-CSF pressure) [36, 37]. Lower venous pulsations are also observed in primary open angle glaucoma [38].…”

Comparison of peripapillary choroidal thickness between healthy subjects and patients with Parkinson’s disease

“…OCT is a useful tool for choroidal studies; nevertheless, the role of choroidal analysis for ocular pathologies is not yet established. Spectral domain-optical coherence tomography (SD-OCT), mostly with enhanced depth imaging (EDI), has been used to evaluate the macular and peripapillary choroid (mainly in healthy eyes and glaucoma patients) [12,13], but the relation of OCT measurements with changes in the peripapillary choroid remain unclear. Some studies report a reduction in the mean or regional peripapillary choroidal thickness (PPCT) in primary open-angle glaucoma [14–16], but in these studies, choroidal thickness was measured manually using SD-OCT at only a few points and beneath the circumpapillary ring, an area typically used for RNFL evaluation.…”