Peripapillary and Macular Vessel Density in Patients with Glaucoma and Single-Hemifield Visual Field Defect
Adeleh Yarmohammadi1, Linda M Zangwill1, Alberto Diniz-Filho1
1Hamilton Glaucoma Center, Shiley Eye Institute, Department of Ophthalmology, University of California San Diego, La Jolla, California.
Purpose:
To compare hemifield differences in the vessel density of the peripapillary and macula in open-angle glaucoma eyes with visual field (VF) defect confined to one hemifield using optical coherence tomography angiography (OCT-A).
Design:
Cross-sectional study.
Participants:
A total of 58 eyes of 58 patients with glaucoma with VF loss confined to a single hemifield and 28 healthy eyes.
Methods:
Retinal vasculature information was summarized as circumpapillary vessel density (cpVD) and perifoveal vessel density (pfVD). Circumpapillary retinal nerve fiber layer (cpRNFL) and macular ganglion cell complex (mGCC) thickness were calculated using spectral domain optical coherence tomography (SD OCT). Paired and unpaired t tests were used to evaluate differences between the perimetrically affected and intact hemiretinae and healthy hemiretinae. Linear regression analyses were performed to evaluate the associations between VF measures with vascular and structural measurements.
Main Outcome Measures:
Total and hemispheric cpVD, pfVD, cpRNFL, mGCC, and mean sensitivity (MS).
Results:
Mean cpVD and pfVD in the intact hemiretinae of glaucoma eyes (59.0% and 51.1%, respectively) were higher than in the affected hemiretinae (54.7% and 48.3%, respectively; P < 0.001) but lower than in healthy eyes (62.4% and 53.8%, respectively; P < 0.001). Similar results were noted with cpRNFL and mGCC thickness measurements (P < 0.05 for both). The strongest associations between MS in the affected hemifields were found for cpVD (r = 0.707), followed by pfVD (r = 0.615), cpRNFL (r = 0.496), and mGCC (r = 0.482) in the corresponding hemiretinae (P < 0.001 for all). Moreover, the correlations in the intact hemifields between MS with cpVD and pfVD were higher (r = 0.450 and 0.403) than the correlations between MS and cpRNFL and mGCC thickness measurements (r = 0.340 and 0.290; P values <0.05 for all).
Conclusions:
Reduced peripapillary and macular vessel density was detectable in the perimetrically intact hemiretinae of glaucoma eyes with a single-hemifield defect. Vessel density attenuation in both affected and intact hemiretinae was associated with the extent of VF damage in the corresponding hemifields. Optical coherence tomography angiography potentially shows promise for identifying glaucomatous damage before focal VF defects are detectable.
