Abstract
Purpose :
As a protrusion from the brain, the retina might reflect (pathological) changes in the brain. There is increasing evidence of retinal microvasculopathy correlating to cerebral small vessel disease (SVD) on MRI. This study compares ocular vascular parameters and SVD in a population of twins.
Methods :
210 (105 monozygotic twin pairs) cognitively healthy individuals (ages 60-100) underwent MRI, fundus photography and optical coherence tomography (OCT). Microbleeds and white matter hyperintensities (WMH, Fazekas score) were visually scored on MRI. Additionally, WMH volume was obtained using FreeSurfer. Fundus images were acquired from both eyes and analyzed using Singapore I Vessel Assessment (SIVA) to obtain 7 retinal vascular parameters (RVPs). Enhanced depth imaging OCT scans from both eyes were used to measure choroid thickness (CT) manually. Ophthalmological data were averaged over both eyes. The intrapair correlations for RVPs, CT and SVD parameters were obtained and relations between RVPs/CT and microbleeds/WMH (Fazekas score and volume) were investigated.
Results :
Intra-twinpair correlations were high for all parameters: 0.553-0.782 (p<0.001 in all cases) for RVPs, 0.834 (p<0.001) for CT and 0.335-0.851 (p≤0.001 in all cases) for SVD parameters.
No correlations were found between RVPs and microbleeds or Fazekas score. Only increased venular tortuosity was related to increased total WMH (r=0.197, p=0.019). This remained significant even after correction for age, gender, total intracranial volume and hypertension. CT was not related to microbleeds, Fazekas score or WMH volume.
Conclusions :
High intra-twinpair correlations for RVPs, CT and SVD markers were found in monozygotic twins, suggesting a high genetic contribution in these vascular parameters. However, only increased retinal venular tortuosity was found to be related to WMH volume on MRI, suggesting retinal vasculature shows little correlation to cerebral small vessel disease despite the high genetic influence on both. The lack of such correlations may be due to the relatively healthy nature of our study population (few people had significant SVD on MRI).
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.