Table 1. Relationship between rate of phagocytosis (PR), rate of ROS degradation (RRD) and formation of lipofuscin

The shedding, internalization and degradation of ROS is a continuous process, perturbations in which could result in increased formation (and consequent accumulation) of lipofuscin. The table describes most plausible conditions of PR and RRD (in the realm of normal physiological possibilities) that could affect lipofuscin formation. A constant PR in combination with constant/increased RRD will not, in theory, facilitate lipofuscin formation. In contrast, constant PR with decreased RRD or increased PR with constant RRD can facilitate lipofuscin formation, conditions which can account for the accumulation of lipofuscin in the etiology of ARMD.

  Rate of                   Rate of ROS
phagocytosis   Lipofuscin   degradation
    (PR)       formation       (RRD)
------------   ----------   -----------
  Increase        Yes        Constant
  Decrease         No        Constant
  Constant         No        Increase
  Constant        Yes        Decrease
  Constant         No        Constant