In addition, it has been reported in one clinical research that the serum level of total oxidant status (TOS, an oxidative stress parameter) was significantly increased by about 167% in 22 AMD patients when compared with that of a group of 25 healthy people, while the levels of two important antioxidant molecules (total thiol status (TTS) and the activity of paraoxonase 1(PON1)) were significantly decreased. Here, PON1 is linked to age-related macular degeneration.