Optic disc blood perfusion and oxygenation in glaucoma

Abstract

Purpose To investigate the haemoglobin concentration and oxygenation in the optic disc in glaucoma patients vs. controls. Methods Thirty-one eyes of primary open angle glaucoma patients (mean age: 64.9 ± 2.1 years) and 31 eyes of 31 healthy controls (65.5 ± 2.0 years) were included. Perimetry, optical coherence tomography (OCT), and OCT angiography were performed. Multispectral imaging was used to record the optic disc reflectance at wavelengths 522 nm, 548 nm, 555 nm, 586 nm, and 610 nm, and haemoglobin concentration and oxygenation (SO2) were calculated from these measures. This was done in the rest and under stimulation of neuronal activity by flicker light. Results The haemoglobin concentration was significantly lower (p < 0.001) in the rim (40.0 ± 6.3) and the excavation (35.7 ± 8.0) of the glaucoma patients’ discs than in controls (45.7 ± 7.5). SO2 was not different in general, but lower in a subgroup of 18 glaucoma patients with ischaemic disc rims than in non-ischaemic ones (median 26.8%, interquartile range (IQR): 29.5% vs. 51.9%, IQR 32.0%, p = 0.02) as well as in controls (41.0%, IQR 30.6%, p = 0.01). Flicker light stimulation significantly increased the haemoglobin concentration in the controls (+ 1.3 ± 3.6, p = 0.048) as well as in the rim of glaucoma discs (+ 2.6 ± 5.0, p = 0.006) and SO2 in the controls only (+ 15.4 ± 23.6%, p = 0.001). The haemoglobin concentration was significantly correlated with the perimetric mean defect, retinal nerve fibre layer (RNFL) thickness and para-papillary perfusion density. Conclusions The optic disc haemoglobin concentration and oxygenation are quantifiable from multispectral imaging and reduced in glaucoma. The correlation of haemoglobin concentration with perfusion density, RNFL thickness and visual field loss indicates its implication in glaucoma pathology.

A multi-color video-ophthalmoscopes allows to measure the spectral distribution of light absorption of blood in the human retina

“…For clinical applications, fast automatic switching between preselected wavelengths could be useful. This could be realized with individual light sources for each wavelength (LED and filter), so that each wavelength can be electronically switched quickly (5). Other light sources are also possible, e.g., the use of a fiber coupled light source.…”

“…Some modifications of commercial fundus cameras to get narrow band multi-color fundus images are described in the literature. Mordant et al ( 4 ) describes the use of a modified fundus camera to obtain sequential hyperspectral images for oximetry within retinal vessels. Al Zoubi et al ( 5 ) uses multispectral imaging to record the optic disk reflectance at wavelengths 522 nm, 548 nm, 555 nm, 586 nm, and 610 nm to calculate hemoglobin concentration and oxygenation (SO 2 ).…”

“…Mordant et al (4) describes the use of a modified fundus camera to obtain sequential hyperspectral images for oximetry within retinal vessels. Al Zoubi et al (5) uses multispectral imaging to record the optic disk reflectance at wavelengths 522 nm, 548 nm, 555 nm, 586 nm, and 610 nm to calculate hemoglobin concentration and oxygenation (SO 2 ). Toslak et al (6) uses four narrowband (17 nm-60 nm) LEDs, (530 nm, 625 nm, 780 nm, and 970 nm) for multispectral imaging with a contact-mode ultra-widefield system with trans-pars-planar illumination.…”

The Relationship between Transcranial Doppler Ultrasonography and Visual Field Test Results in Glaucoma and Glaucoma Suspect Patients

“…Some meta-analyses have demonstrated cardiovascular disease as a risk factor for open-angle glaucoma [ 5 , 6 ]. Other studies have focused on the decrease in blood perfusion of glaucoma patients compared with normal participants [ 7 , 8 ] and vascular dysregulation leads to low blood perfusion pressure and provokes ischemia and optic nerve damage [ 9 ].…”