1. A method for diagnosing a condition of an eye, the method comprising: projecting light at the eye; recording lipofuscin fluorescence from a retina of the eye to form a first image of the retina; processing the first image to make an image clarity determination regarding a level of conformance of the first image to at least one image clarity criterion, comprising: creating a pixel intensity histogram for the first image of recorded lipofuscin fluorescence; and assessing a base width of the pixel intensity histogram; determining whether the first image can reliably indicate a macular pigment content of the retina based on the image clarity determination; and calculating the macular pigment content of the retina, comprising: measuring the macular pigment content based on the image; determining a correction factor that is derived from the base width of the pixel intensity histogram, wherein the correction factor adjusts the macular pigment content to account for at least one cataract in the eye, wherein the correction factor decreases with increasing base widths; and multiplying the measured macular pigment content by the correction factor to determine an estimated macular pigment content of the retina that would be measured if the at least one cataract was removed from the eye.