The Effect of Eggs and Egg Products on Macular Pigment

Overview

Age-related macula degeneration (AMD, encompassing both dry and wet form), the late stage of Age-related maculopathy (ARM), is the leading cause of blindness in many developed countries in older persons (usually over 60 years of age). Visual compromise rises exponentially after the age of 70 with a 5-year incidence of around 1%. Studies have shown a possible protective effect of lutein on progression of AMD, where visual acuity improves after increased lutein intake. The incidence of bilateral AMD in persons with unilateral late ARM observed over a period of 10 years is over 50% with a 2.1-2.8% overall incidence in the study population. Blue light hazard (excitation peak 440 nm) was shown to have a major impact on photoreceptor and RPE function inducing photochemical damage and cellular apoptosis, leading to retinal degeneration in an animal study. The current belief is that lutein accumulated in the macular region helps in the prevention of blindness by absorbing blue light and protecting the retina from oxidative stress. With the lipid matrix of the egg yolk being a proven vehicle for the efficient absorption of dietary lutein, it might be possible to increase plasma levels of lutein to therapeutic levels and control or prevent AMD. This, the investigators hope, will be accomplished by means of filtering out harmful blue light and the scavenging of free radicals by lutein and zeaxanthin.

This will be a randomized placebo-controlled trial. The total study time will be two years of which 3 months are actual trial and follow-up time. Every individual will have 3 measuring points at set intervals. At every measuring point (days 1, 45 and 90), these subjects will undergo 6 different non-invasive measuring techniques. These are the mean visual acuity test using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart, contrast sensitivity using the Pelli-Robson chart, Scanning Laser Ophthalmoscope (SLO), Optical Coherence Tomography (OCT) and Heterochromatic Flicker Photometry (HFP) and the Reflectometer. A questionnaire will be taken at the beginning of the trail. The invasive part of the study involves blood sampling at all three times, measuring the serum concentration of lutein, zeaxanthin, omega-3 and lipoprotein using the HPLC analysis.