Quantitative autofluorescence and its correlates in health and disease

Abstract

Retinal lipofuscin is an autofluorescent waste product that accumulates in the retinal pigment epithelium. The majority of retinal lipofuscin is believed to be generated as a by-product of the visual cycle from phagocytosed photoreceptor outer segments. It has been well established that lipofuscin accumulates in the retina with age and it is thought to generate reactive oxygen species. It was previously hypothesised that lipofuscin plays a role in the pathogenesis of AMD. Lipofuscin can be visualised and quantified using a technique called Quantitative Autofluorescence imaging (qAF) as described by Delon and colleagues in 2011. The technique incorporates a reference material of known fluorescence into the imaging device to allow the fluorescence of the fundus to be estimated. This facilitates the comparison of autofluorescence images captured at different sites and at different time points. These analyses have used qAF data from Wave 1 of the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA). The relationship between Macular Pigment Optical Density (MPOD) and qAF was investigated and found that there was only a statistically significant relationship between qAF and MP closest to the fovea where MP is at its highest concentration. The relationship between AMD and qAF was also explored and found that qAF is not predictive of the presence of AMD or the stage of AMD. qAF was studied in participants with diabetes and results showed that qAF in those with diabetes and with ocular disease did not differ from control participants but those with diabetic retinopathy had a lower qAF when compared to controls. The NICOLA study represents the largest qAF study to date and this thesis details preliminary analysis using the data available with the potential for further analysis in conjunction with other measurements taken as part of the study.

Date of Award	Jul 2019
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Tunde Peto (Supervisor), Ruth Hogg (Supervisor) & Imre Lengyel (Supervisor)