Peripapillary choroidal volume in eyes with and without primary open-angle glaucoma

Abstract

 

Purpose

 

To compare peripapillary choroidal volume (PCV) in normal eyes versus eyes diagnosed primary open-angle glaucoma and ocular hypertension.

 

Methods

 

We imaged consecutive subjects who were participating in a longitudinal, observational clinical research study and who were diagnosed primary open-angle glaucoma (POAG), ocular hypertension (OH), or normal (NML). Using spectral domain optical coherence tomography with enhanced depth imaging, we acquired twelve 20-degree (approximate 6mm length) radial scans centered on the optic nerve head; each radial scan was separated by 15 degrees. Using a customized Matlab software program, choroidal thickness was quantified for each scan and adjusted for ocular magnification. PCV measures were then calculated using standard linear interpolation techniques. We compared PCV between diagnostic groups using one-way analysis of variance (ANOVA), and we used regression analyses to evaluate relationships between PCV and age, intraocular pressure, ocular pulse amplitude (OPA), central corneal thickness, mean retinal nerve fiber layer thickness (RNFL), visual field indices (mean defect [MD], pattern standard deviation [PSD]), diabetes diagnosis, and glycosylated hemoglobin levels.

 

Results

 

We imaged 103 consecutive subjects, obtaining PCV measures in 191 eyes (86 POAG, 55 OH, 50 NML eyes). Image quality prevented PCV measurement in 15 eyes (7.2%). Overall, PCV demonstrated large inter-individual variability with a 4-fold difference between thinnest and thickest PCV measures. Among all eyes, PCV was significantly thinner (p<0.001) in POAG (1070 μm³) compared to OH (1276 μm³⁾ and NML eyes (1334 μm³⁾ with similar results when right and left eyes were evaluated separately. In multivariate regression analyses, glaucoma diagnosis, age, and ocular pulse amplitude (OPA) were independently associated with PCV (age was inversely related while OPA was directly related). Notably, parameters associated with glaucoma severity (RNFL, MD, PSD) were not independently associated with PCV.

 

Conclusions

 

Peripapillary choroidal volume appears to be reduced in eyes with POAG compared to NML and OH eyes. Whether thinner PCV reflects inherent risk for POAG or represents acquired change that occurs as part of the glaucoma pathophysiologic process requires further study.

 

 

Keywords: 452 choroid • 550 imaging/image analysis: clinical