Drusen are pale yellow spots that occur individually or in clusters throughout the macula. Nearly all individuals over the age of 50 years of age have at least one small drusen (?< 63 lam) in one or both eyes .
They con-sist of amorphous material accumulated between Bruch's membrane and the pig-ment epithelium. Although the exact origin is not known, it is believed that driJsen occur due to the accumulation of lipofuscin and other cellular debris derived from cells of the retinal pigment epithelium that are compromised by age and other fac-tots.
Only eyes with large dr0sen (>63 lam) are at increased risk for senile macular degeneration.