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06 Apr 18. Featured paper

Peripheral retinal imaging biomarkers for alzheimer's disease: a pilot study.

Link to paper on Karger Publishers. 

 

Authors

Csincsik L, MacGillivray TJ, Flynn E, Pellegrini E, Papanastasiou G, Barzegar-Befroei N, Csutak A, Bird A, Ritchie CW, Peto T, Lengyel I

Abstract
Purpose

To examine whether ultra-widefield (UWF) retinal imaging can identify biomarkers for Alzheimer's disease (AD) and its progression.

Methods

Images were taken using a UWF scanning laser ophthalmoscope (Optos P200C AF) to determine phenotypic variations in 59 patients with AD and 48 healthy controls at baseline (BL). All living participants were invited for a follow-up (FU) after 2 years and imaged again (if still able to participate). All participants had blood taken for genotyping at BL. Images were graded for the prevalence of age-related macular degeneration-like pathologies and retinal vascular parameters. Comparison between AD patients and controls was made using the Student t test and the χ2 test.

Results

Analysis at BL revealed a significantly higher prevalence of a hard drusen phenotype in the periphery of AD patients (14/55; 25.4%) compared to controls (2/48; 4.2%) [χ2 = 9.9, df = 4, p = 0.04]. A markedly increased drusen number was observed at the 2-year FU in patients with AD compared to controls. There was a significant increase in venular width gradient at BL (zone C: 8.425 × 10-3 ± 2.865 × 10-3 vs. 6.375 × 10-3 ± 1.532 × 10-3, p = 0.008; entire image: 8.235 × 10-3 ± 2.839 × 10-3 vs. 6.050 × 10-3 ± 1.414 × 10-3, p = 0.004) and a significant decrease in arterial fractal dimension in AD at BL (entire image: 1.250 ± 0.086 vs. 1.304 ± 0.089, p = 0.049) with a trend for both at FU.

Conclusions

UWF retinal imaging revealed a significant association between AD and peripheral hard drusen formation and changes to the vasculature beyond the posterior pole, at BL and after clinical progression over 2 years, suggesting that monitoring pathological changes in the peripheral retina might become a valuable tool in AD monitoring.

 
Keywords
  • Age-related macular degeneration
  • Alzheimer’s disease
  • Drusen
  • Fractal dimension
  • Image grading
  • Imaging
  • Peripheral retina
  • Tortuosity
  • Vascular biomarker