Abstract
Purpose :
The aim of this study was to correlate the optical coherence tomography angiography (OCTA) parameters with thickness of individual retinal layers using spectral domain-optical coherence tomography (SD-OCT) in type 1 diabetes mellitus (DM1).
Methods :
Fifty-six eyes of 56 patients diagnosed with DM1 with no or mild signs of non-proliferative diabetic retinopathy (DR) at IRCCS - Bietti Foundation were included in this cross-sectional clinical study. OCTA imaging was performed using RTVue-XR Avanti (Optovue Inc, Fremont, California, USA) and foveal as well as parafoveal vessel density in superficial capillary plexus (SCP) and the deep capillary plexus (DCP) was calculated with automated quantification software. Measurements of central retinal thickness (CRT) and individual retinal layer thickness were obtained using SD-OCT automated segmentation algorithm by means Spectralis HRA-OCT (Heidelberg Engineering, Heidelberg, Germany).
Relationships between foveal, parafoveal vessel density (VD) as well as whole (foveal and parafoveal) values and single retinal layer thickness were explored. The Spearman’s correlation coefficient was calculated to evaluate the correlation among OCTA values and retinal thickness parameters.
Results :
CRT thickness was highly correlated with both VD values of foveal SCP and DCP. A moderate to good correlation was found between retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer thickness (INL) and all VD parameters of SCP. In addition, all previous retinal thickness layers mentioned showed a significant correlation with foveal DCP. The VD of whole DCP showed a good correlation with RNFL, GCL, IPL and INL thickness, whereas a statistically significant correlation was found only between the GCL thickness and the parafoveal DCP vessel density. No significant association between outer retinal layers and OCTA parameters was found. (See table 1 for details)
Conclusions :
OCTA parameters showed a significant correlation with inner retinal layers thickness in DM1patients with no or early signs of DR. Foveal VD at the level of the SCP and DCP showed a good correlation with GCL and INL thickness. Structural and vascular abnormalities are strictly correlated in DR and might represent early biomarkers of damage.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.