Degeneration is deterioration in the medical sense. Generally, it is the change from a higher to a lower form. More specifically, it is the change of tissue to a lower or less functionally active form. True degeneration: when there is actual chemical change of the tissue itself. Infiltration: when the change consists of the deposit of abnormal matter in the tissues Degenerative disease See also Macular degeneration Neurodegenerative disease References Dorland's Illustrated Medical Dictionary (Twenty-sixth Edition) () Medical terminology