Figure 7.

A, B, Time-of-flight secondary ion mass spectroscopy of deposits in the space between the basal lamina of the retinal pigment epithelium (RPE) and the inner collagenous layer of Bruch’s membrane (sub-RPE–BL) containing numerous spherical particles. A, A1, A2, Single representative mass spectrum obtained from a sub-RPE–BL deposit containing numerous spherical particles. Secondary molecular ions corresponding to calcium, phosphate, and multiple calcium phosphate fragments ions were readily detectable within the region of interest. B, A secondary ion map showing that calcium phosphate fragment ions (red) localize to spherical particles, whereas the secondary molecular ions associated with proteins (green) are localized to organic matter and soft tissues. Scale bar: 100 μm. Asterisk indicates drusen, arrowhead indicates BrM. Ca = calcium; Chr = choroid; H = hydrogen; O = oxygen; P = phosphorus; POS = photoreceptor outer segment.