**4. Calcified soft Drusen**

This type of drusen originates from classical drusen that had their colloidal content mineralized along time. While classical drusen have a hyperreflective content due to the presence of colloid, calcified drusen have hyporreflective nodules that correspond to hydroxyapathite crystals [23].

Calcified drusen have a glistening appearance due to calcium-containing spherules and a depigmentation area around them. They present with reduced autofluorescence. On OCT, they appear as hyperreflective dots on a hyporreflective base, and they can cause shadowing of deeper structures (**Figure 3**). Refractile deposits within drusen may indicate a higher rate of GA development.

There are three calcified structures associated with advanced AMD: 1) small hyperreflective dots within drusen; [2] heterogeneous internal reflectivity within drusen (HIRD) and 3) hyperreflective lines near the Bruch's membrane. The composition of HIRD and the reason of its hyporreflectivity was not determined yet [24].
