1. A device for measuring the auto-fluorescence of a retina comprising: an excitation light source adapted to provide an excitation light at a wavelength corresponding to excitation of flavoprotein auto-fluorescence; and an image capture device adapted to record a single image representative of a retinal fluorescence signal generated in response to the excitation light, the image capture device including: a filter that reduces background wavelengths from the retina fluorescence signal; and an image intensifier adapted to increase the retinal fluorescence signal strength.