Optic Nerve Head Blood Flow, Damage Location May Affect Vision in Glaucoma

Optic nerve head blood flow and the location of visual field damage may determine visual outcomes in patients with glaucoma and myopia, according to research published in the American Journal of Ophthalmology.

Researchers included 60 patients with myopia and glaucoma (eyes, 65) in a retrospective, cross-sectional study to investigate factors associated with visual functioning. Study participants underwent 24-2 and 10-2 visual field testing along with optical coherence tomography-angiography (OCT-A) to determine superficial and deep vessel density in the peripapillary and macular and retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses. The team also obtained optic nerve head structural parameters, including β-zone peripapillary atrophy area, disc torsion, disc-fovea distance, and peripapillary choroidal thickness measurements.

The presence of central visual field damage was associated with the worse mean 24-2 visual field deviation (β, 0.447; 95% CI, 0.1748-0.715; P =.002), thinner GCIPL thickness (β, 0.195; 95% CI, 0.004-0.386; P =.046), and lower deep peripapillary vessel density (β, 0.530; 95% CI, 0.225-0.835; P =.001), according to the report.

Logistic regression analysis revealed that thinner GCIPL thickness (β, -0.182; 95% CI, 0.728-0.954; P =.008), lower deep peripapillary vessel density (β, -0.241; 95% CI, 0.652-0.947; P =.011), and longer disc-fovea distance (β, 0.062; 95% CI, 1.010-1.121; P =.021) were associated with decreased visual acuity (worse than 20/25). The report shows a positive correlation between deep peripapillary vessel density and GCIPL thickness and revealed no association between deep peripapillary vessel density and RNFL thickness.

“Structural changes owing to myopia may affect the vascular component, which may lead to glaucomatous damage in myopic eyes,” according to the study authors. “We proposed that lower deep peripapillary [vessel density] and papillomacular bundle damage may result from deformation and vessel compression of the peripapillary sclera, and both structural changes and vascular insufficiency may lead to decreased [visual acuity] in addition to central [visual field] damage.”

Study limitations include a failure to correlate myopic structural change and axial length.