Abstract
Purpose :
Optical Coherence Tomography Angiography (OCTA) is a non-invasive technology that allows the study of the vascularization of the optic disc. We intended to assess the vessel density (VD) of the peripapillary region, whole-image and capillary VD of glaucoma patients, in comparison with controls, using an automated software.
Methods :
We performed an observational, cross-sectional study, with 72 open-angle glaucoma patients and 30 age-matched healthy controls, after written consent and Ethics Committee approval. All participants underwent Goldmann applanation tonometry, gonioscopy, optic disc photography, pachymetry, Optical Coherence Tomography (OCT) and OCTA imaging with Triton (OCT Triton Swept source, Topcon, Japan), and visual field (VF) testing. For OCTA, scans of 4.5x4.5 mm were centered on the optic nerve head and images of poor quality (signal strength index < 50, motion artifacts) were excluded. Since this device does not quantify vessel density, we built a software (with Visual Studio and In-Sight Explorer) that allowed us to quantify VD, to remove major blood vessels and to quantify the capillary density in the peripapillary region (CVD), as well as total VD in the peripapillary region (PVD), whole-image optic nerve head VD (WVD) and color image VD (CoVD). We used areas under the receiver operating characteristic curves (AUROCs) to evaluate diagnostic accuracy. We also verified whether CP was correlated with visual field mean deviation.
Results :
VD was lower in glaucoma than in controls (mean VD in percentage ± standard deviation, P; Mann-Whitney independent sample test): WVD of 72,45± 7,45 in glaucoma and 77,87±3,77 in controls; P<0,001; CVD of 74,57 ± 5,31 in glaucoma and 77,09± 2,98 in controls, P=0,375; CoVD of 56,97± 11,69 in glaucoma and 57,14±13,23 in controls, P=0,031. VD values were correlated with the visual fields (Spearman correlation of 0,33; P 0,0017). AUROC were moderate (CoVD 0,629 ± 0,143), but better than AUROC of visual field (0,229±0,077) or AUROC of the retinal nerve fiber layer thickness assessed by OCT (0,326±0,064).
Conclusions :
This custom automated program is useful for quantifying total and capillary peripapillary VD, as well as whole-image VD, and for documenting the changes of vascularization in glaucomatous eyes. OCTA might be a useful tool for the diagnostic and prognosis of glaucoma in the near-future.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.