What color change does Thimerosal cause in contact lenses?

Thimerosal, a mercury-containing compound often used as a preservative in some contact lens solutions, can cause a color change in certain types of contact lenses. Specifically, it can lead to a brownish or reddish discoloration. This reaction is particularly noted in soft contact lenses that may absorb the chemical, resulting in a staining effect. The mechanism behind this involves the interaction of Thimerosal with certain lens materials, which may alter the optical properties and appearance of the lenses.

When considering other choices, they do not accurately reflect the specific interactions that occur between Thimerosal and contact lens materials. The assertion that Thimerosal turns lenses black or yellowish does not align with observed effects, nor is it correct to state that it does not change color at all. Understanding how certain preservatives can affect lens coloration is essential for ensuring the safety and comfort of contact lens wearers.