Abstract
Purpose :
The neurosensory retina and the brain have the same origin and share morphologic and physiologic similarities. Changes in several retinal layers assessed by spectral domain – optical coherence tomography (SD-OCT) have been described in neurodegenerative diseases. To date, however, only little is known about the relationship of the retina and the brain in a general population using high-resolution imaging techniques such as SD-OCT and magnet resonance imaging (MRI). In order to better understand the significance of retinal alterations observed in neurodegenerative diseases the relationship of the retina and the brain in the general population needs to be characterized.
Methods :
In the Rhineland Study (www.rheinland-studie.de) we performed SD-OCT scans (Spectralis, Heidelberg Engineering) and generated data on retinal layers using the in-built segmentation algorithms of the Heidelberg Eye Explorer (HEYEX). HEYEX enables the automatic delineation of all macular layers including the outer retina as well as Bruch’s membrane opening – minimal rim width (BMO-MRW) around the optic disc. Grey (GM) and white matter (WM) volumes were automatically determined on T1 MPRAGE images (3 Tesla Prisma MRI Siemens) using FreeSurfer 6.0 (based on the APARC atlas for GM and WM). We assessed associations between retinal layers and brain volumetric measures using multivariable regression adjusted for potential confounders and multiple testing.
Results :
Complete data on SD-OCT and MRI were available from 1.064 individuals whose age ranged from 30 to 95 years (mean (SD) 53.0 ± 13.5). We found the ganglion cell layer (GCL) and inner plexiform layer (IPL) to be associated with both, global and occipital GM and WM volumes (p<0.001). Moreover, the outer retina was associated with global GM (p=0.001), while the peripapillary retinal nerve fiber layer (pRNFL) was associated with global and occipital WM (p<0.001). In contrast, BMO-MRW was associated with neither MRI marker.
Conclusions :
Our results confirm the association of the inner retina with GM and WM, both globally and in the occipital lobe. Furthermore, our data indicate that the outer macular retina, mainly composed of photoreceptors and the RPE, is associated with global GM volume. Further studies are needed to validate these findings and to address their implication for assessing retinal changes in neurodegenerative diseases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.