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Low-level night-time light therapy for age-related macular degeneration

Robinson, David Grant 2017. Low-level night-time light therapy for age-related macular degeneration. PhD Thesis, Cardiff University.
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Abstract

Age-related macular degeneration (AMD) is the leading cause of visual impairment in the developed world (Wong et al., 2014). The exact causes of AMD are unclear but hypoxia has been implicated (Stefánsson et al., 2011). If hypoxia has a role in the pathogenesis of AMD treatments that mitigate the effect of retinal hypoxia may slow disease progression. This thesis aimed to establish the impact of light therapy, as delivered using a light emitting mask, on the progression of AMD. A phase I/IIa randomised controlled trial was implemented in which 60 participants with early and intermediate AMD were allocated to the intervention or the untreated control group in a 1:1 ratio and monitored over 12 months. The ability of secondary outcome measures (including: rate of cone dark adaptation, 14Hz flicker threshold and chromatic thresholds) to identify the likely risk of progression from early and intermediate AMD to advanced AMD was also assessed in a cross-sectional study evaluating the relationship between each baseline outcome measure and the severity of fundus changes. Sixty participants were recruited of which 47 (20 intervention, 27 control) completed the 12 month follow-up period. No significant difference was found in the change of any parameter between groups apart from the time constant of cone-photoreceptor recovery (cone τ), which was increased to a greater extent in the treated group. An additional 40 participants were recruited to the cross-sectional study (n=100). Measurement of cone τ was identified as the best independent predictor of increased AMD severity based on the AREDS Simplified Severity Scale (Ferris et al., 2005). Although a greater proportion of controls (48%) than mask wearers (38%) showed disease progression over the duration of the trial this difference did not reach statistical significance.

Item Type: Thesis (PhD)
Status: Unpublished
Schools: Optometry and Vision Sciences
Subjects: R Medicine > RE Ophthalmology
Uncontrolled Keywords: Age-related macular degeneration, Retinal hypoxia Light therapy, Phase I/II clinical trial
Last Modified: 21 Feb 2018 09:27
URI: http://orca.cf.ac.uk/id/eprint/108368

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