Argyria or argyrosis is a disease caused by being exposed to too much silver. People with this condition may have a change in skin color to blue or "greyish". A study has said that having argyria makes it harder to see without light.[1]
Argyria Media
Colloidal silver is illegally marketed as a medicine, but has not proven to treat any condition, and has the potential to pathologically interfere with the functioning of many critical medications, such as antibiotics and thyroxine.
References
↑Rosenman, K. D.; Moss, A.; Kon, S. (June 1979). "Argyria: clinical implications of exposure to silver nitrate and silver oxide". Journal of Occupational Medicine.: Official Publication of the Industrial Medical Association. 21 (6): 430–435. ISSN0096-1736. PMID469606.