With each new discovery about the opaque pathogenesis of glaucoma, the mystery deepens. Back in the 80s and 90s, researchers made some progress by uncovering an association between primary open-angle glaucoma (POAG) and vascular pathologies.1,2 Investigators reviewed details of anatomical structures such as vessel caliber and peripapillary retinal vessel diameters, as well as how conditions such as arteriolar narrowing affect retrobulbar and retinal blood flow.1,2 And this research did illuminate some aspects of glaucoma’s development, for instance that arteriolar narrowing was more common in patients with glaucoma than in patients with ocular hypertension and that peripapillary retinal vessel diameters were significantly smaller in eyes with glaucoma than without.1,2 But that research raised further questions. If the arteriolar caliber is associated with POAG, is arterial wall thickness also a factor? The mystery deepens. With adaptive optic technologies, researchers may have some new answers and, perhaps, some new questions.3
Using adaptive optics imaging, a French research team observed a narrowing of the arteriolar lumen without modification of the vessel wall thickness in POAG patients.3 The team concludes that this finding suggests that vascular risk factors in POAG only reduce the vascular caliber without inducing any patent atherosclerosis of the retinal arterial wall.3 Using the advanced technology, the investigators took five measurements at different locations of each analyzed vessel of 31 glaucoma patients and 29 healthy controls.3 For each location, the investigators measured lumen diameter (LD) and wall thickness and calculated total diameter (TD), wall-to-lumen ratio (WLR) and whole-cross-sectional area (WCSA).3
The study shows LD and TD are significantly lower in glaucoma patients than healthy controls.3 Wall thicknesses, WLR and WCSA were not significantly different, although WLR was significantly higher in subjects with high cholesterol. The researchers noted no other correlation between patients’ clinical characteristics and any of the parameters.3
“This observation suggests that the vascular risk factors associated with POAG do not seem to induce any patent wall modification of the retinal arterial wall,” the researchers explain in their paper.3
|1. Jonas JB, Nguyen XN, Naumann GO. Parapapillary retinal vessel diameter in normal and glaucoma eyes. I. Morphometric data. Invest Ophthalmol Vis Sci. 1989;30:1599-1603.|
2. Rankin SJ, Drance SM. Peripapillary focal retinal arteriolar narrowing in open angle glaucoma. J Glaucoma. 1996;5:22-28.
3. Hugo J, Chavane F, Beylerian M, et al. Morphologic analysis of peripapillary retinal arteriole using adaptive optics in primary. J Glaucoma. January 21, 2020. [Epub ahead of print].