OCT Angiography of the Optic Nerve Head to differentiate normal from glaucoma eyes

Abstract

Purpose : To evaluate the ability of optic nerve head (ONH) perfusion parameters as assessed by AngioVue OCT in discriminating normal from manifest glaucoma eyes. To also explore the linear relationship between the AngioOCT derived perfusion parameters with structural and functional retinal conventional measurements

Methods : Eighty two eyes from 41 healthy subjects and 41 glaucomatous patients were enrolled. All patients underwent a full eye examination, standard achromatic perimetry (SAP) we Humprey field analyzer and were imaged with SD-OCT RTVue-XR Avanti. Two scanning protocols, Angio 3D OCT and ONH were acquired in sequence. Angio3D disc analysis measures flow density (%) at two level, nerve head (NH) and radial peripapillary capillary (RPC). Glaucoma was defined on the basis of SITA-24-2 visual field loss (PSD and MD p<5% and Glaucoma Hemifield Test outside normal limits) on two consecutive visual fields. T-test was used to explore differences in angioOCt parameters between normal and glaucoma. Areas under receiver operating characteristic curve (AUC) were calculated as measure of discriminating ability. Sensitivity at 90% fixed specificity were also evaluated for all the parameters. To evaluate the relationship betweeen perfusion parameters and structural-functional variables, we performed a linear regression analysis. A p value below 0.05 was considered statistical significantly.

Results : Several ONH OCT derived perfusion parameters have shown statistically significant differences between normal and glaucoma. At NH level the Insidedisc parameter offered the higher AUC: 0.957 (CI, 0.920-0.994) with a sensitivity of 80% at 90% fixed specificity. At RPC level the insidedisc parameter still showed the best AUC, 0.968 (CI 9.37-0.998) with a sensitivity of 87% at 90% fixed specificity. Among glaucoma patients the Insidedisc at NH level have shown the higher coefficient of determination with MD (r²:0.45), whereas the Wholedisc parameter at RPC level have shown the best correlation with RNFL average parameter (r²:0.67)

Conclusions : AngioVue OCT derived perfusion parameter have shown a good ability in discriminating healthy from glaucomatous eye and a good linear correlation with structural-functional conventional measurements.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.