|Measuring the hemoglobin concentration in the optic nerve head may aid in glaucoma diagnosis. Photo: RetinAlyze. Click image to enlarge.|
Evidence suggests hemoglobin concentration in the optic nerve head is associated with the development and progression of glaucoma, which could offer optometrists another diagnostic method. Software called Laguna OnhE, used in a device called RetinaLyze (not available in the US), measures the hemoglobin concentration throughout the optic nerve head and has shown promise in the diagnosis of moderate and advanced glaucoma.
However, verification of the diagnostic accuracy of this device among patients with mild glaucomatous damage is necessary. Thus, researchers recently conducted a retrospective case-control study of eyes from 58 mild primary open-angle glaucoma patients and 64 healthy subjects.
The researchers used OCT to gather retinal nerve fiber layer thickness measurements of all eyes. They also obtained optic disc photographs, which were analyzed with Laguna ONhE software to measure the amount of hemoglobin in 24 sectors of the optic nerve head. Glaucoma discriminant function was also calculated with this software.
Data showed that the mean retinal nerve fiber layer thickness and vertical cup/disc ratio of the control and glaucoma groups was 90.0±10.6μm vs. 66.28±9.85μm and 0.50±0.09 vs. 0.65±0.09, respectively. The researchers reported that both total hemoglobin and glaucoma discriminant function were significantly higher in the control group compared with the glaucoma group. They also observed significantly higher hemoglobin concentration in 21 of the 24 sectors in the control vs. glaucoma cohorts.
“Our results suggest that the Laguna ONhE software, an accessible method to diagnose glaucoma based on fundus photographs, shows good diagnostic accuracy to differentiate normal eyes from eyes with mild glaucoma,” the study authors concluded. “Longitudinal studies with a larger number of patients are necessary to confirm our findings and to evaluate if this technology can be employed in the follow-up of glaucoma patients.”
Meneses LS, Ciarlini LR, Ayub G, et al. Discrimination between healthy eyes and those with mild glaucoma damage using hemoglobin measurements of the optic nerve head. J Glaucoma. March 29, 2022. [Epub ahead of print].