Laser Doppler Flowmetry in Asymmetric Glaucoma

Abstract

Purpose. To evaluate the relationship between extent of glaucoma damage and optic nerve blood flow, we investigated optic nerve head blood flow in patients with asymmetric glaucoma damage between their two eyes and also in glaucomatous eyes with asymmetric damage inferiorly versus superiorly. Methods. From our institutional practice, 16 subjects with asymmetric glaucoma damage between their two eyes and 25 eyes of 20 patients with asymmetric damage superiorly versus inferiorly were included in the study. Determinations of relative optic nerve head blood flow, velocity, and volume were obtained with laser Doppler flowmetry in the superotemporal and inferotemporal neuroretinal rim and in the cup. Means of flow (Flow₃), velocity (Vel₃), and volume (Vol₃) were calculated from these three measurement sites, and eyes or hemidisks with greater glaucomatous damage were compared to eyes or hemidisks with less damage. Results. For subjects with asymmetric glaucoma damage between eyes, Flow₃ and Vel₃ were significantly lower in the eyes with worse glaucoma damage (mean difference=2.09, p=0.005, and mean difference=0.05, p=0.002, respectively). When comparing optic disks displaying within-eye asymmetry, the hemidisk with greater damage showed significantly lower blood velocity than the hemidisk with less damage (mean difference=0.05, p=0.013); however, no difference in blood flow or volume was detected. Conclusions. This study provides additional evidence that impaired optic nerve circulation is associated with the extent of glaucomatous pathology.

KEYWORDS:

• asymmetric glaucoma
• glaucoma
• laser Doppler flowmetry
• optic nerve blood flow