AbstractAge-related macular degeneration (AMD) is the most common cause of severe visual impairment affecting older adults in the developed world. The pathogenesis of AMD is not fully understood.
This study sought to investigate the association between macular pigment optical density (MPOD) and glare recovery time (GRT) with a selection of other confirmed and putative AMD risk factors (RF): age, gender, body mass index (BMI), calculated percentage body fat (%BF), iris colour, family history (FH) of AMD, and ocular vascular perfusion (OVP) RF: migraine, Raynaud's phenomenon (Rph) and vascular dysregulation (VDys). Interocular comparison was assessed for MPOD and GRT. The effect of ocular dominance on MPOD and GRT, and GRT repeatability was also examined. The use of GRT as a surrogate measure for MPOD was assessed.
In this healthy, mixed-gender, White population no significant association was found between MPOD measured by heterochromatic flicker photometry (HFP) at 0.5° eccentricity and any AMD or OVP RF assessed by this study. No significant interocular difference in MPOD was found. No significant association was found between MPOD and ocular dominance.
GRT after 30-second duration bleach using the direct ophthalmoscope was significantly and positively associated with age. No significant association was found for any other AMD or OVP RF examined, after correction for age. No significant interocular difference was found. No significant association was found with ocular dominance. GRT intra-session repeatability was good and inter-session repeatability was moderate. This method of GRT was not found to be a good surrogate measure for MPOD.
This study generated three new theories: the possible association between the OVP RF migraine, Rph and VDys and AMD risk, the Müller cell (Mc) / neuroglial cell hypothesis for macular pigment, and the retinal theory for Meares-Irlen syndrome (MIS) also known as Visual Stress.
|Date of Award||11 Sept 2015|
|Supervisor||Hannah Bartlett (Supervisor) & Frank Eperjesi (Supervisor)|
- cone-specific visual cycle
- direct ophthalmoscope
- ntrinsically photosensitive retinal ganglion cells
- MPS screener
- Müller cells