Normal-tension glaucoma (NTG) patients with single-hemifield damage may have significantly reduced retinal blood flow in the damaged hemisphere, a study in the British Journal of Ophthalmology suggests. The research team also found retinal blood flow decreased in the normal and damaged hemispheres of NTG eyes compared with the healthy hemisphere independent from retinal nerve fiber layer (RNFL) thickness.

The researchers used doppler OCT to measure temporal artery and temporal vein retinal blood flow. Additionally, they measured RNFL thickness with spectral-domain OCT.

The study enrolled 43 consecutive eyes of 43 patients with NTG with visual field defects confined to a single hemifield, and 24 eyes of 24 age-matched, healthy subjects.

The researchers noted temporal artery and temporal vein retinal blood flow and RNFL thickness were reduced in the damaged hemisphere compared with the normal hemisphere (3.61µL/min vs. 5.86µL/min, 5.61µL/min vs. 6.94 µL/min, 69.0µm vs. 99.7µm). The values in the normal hemisphere of NTG eyes also decreased compared with the healthy hemisphere of the healthy eyes.

Additionally, normal and damaged hemispheres and RNFL thickness were associated with retinal blood flow reduction. In the normal hemisphere, retinal blood flow was lower than measurements in the healthy hemisphere even after adjusting for RNFL thickness.

Yoshiok T, Song Y, Kawai M, et al. Retinal blood flow reduction in normal-tension glaucoma with single-hemifield damage by Doppler optical coherence tomography. Br J Ophthalmol. March 26, 2020. [Epub ahead of print].