Macular pigment is a yellowish pigment found at the central part of the retina of the human eye. It is believed to have two distinct roles: it protects the photoreceptors from photochemical damage by blocking high energy blue light, and it acts as an anti-oxidant, dealing with the harmful free radicals in the retina. It consists of three carotenoids that are of purely dietary origin and its density in the eye can be affected by a number of factors such as obesity and smoking.
Recent studies have found a correlation between the macular pigment and an Age-Related Macular Degeneration (AMD), one the leading causes of blindness in the Western world, making its assessment critical for retinal health. Currently, however, there is only a small number of commercial devices to assess the optical density of macular pigment, that are suitable for clinical use. The most common one is based on a psychophysical technique called Heterochromatic Flicker Photometry but it requires time and typically only healthy subjects can carry out the required task successfully.
The lack of an accurate, rapid and low-cost instrument is the main reason that this, otherwise important, pigment is not part of standard eye care. The objective of this project is to build an objective, non-midriatic instrument which will assess the macular pigment in a precise, rapid and accurate way. The instrument will be built around a patented technology invented by the participants in the project, based on fundus reflectometry.
The method illuminates the ocular fundus with pulses of structured light of different wavelengths using LED, and the intensity of the reflected light is measured using a high-speed photodetector. Subsequently, with the appropriate processing of the signal, the macular pigment optical density can be calculated fast and accurately.
This innovative method minimises light exposure of the fundus and it simplifies largely the measurement compared to the other techniques. No input from the patient is needed from the measurement and we introduced a stereo-camera system for fast pupil alignment. Such an instrument can be proven valuable both in research but also in clinical practice: We foresee that it will help establish the correlation between AMD and the optical density of macular pigment and potentially other retinal disease or health factors, but, most importantly, it has the potential to became part of the standard eye test to help prevent from AMD.