Contact lenses: Introducing aloe vera

Multipurpose solutions are designed to clean, disinfect and maintain contact lenses. For this purpose, they variously include a combination of surfactants, anti-microbial agents (preservatives), a buffer system and agents which control tonicity to the solution. However, a problem may arise due to the inclusion of these very agents, particularly the antibacterial preservatives.

Toxicity of preservative agents

The mechanism of action of preservatives is based on the disruption of the life cycles of individual microorganisms so preventing their proliferation. Therefore, the use of preservatives or disinfectants in solutions that come into contact with the eye (for example in multipurpose solutions and lubricating drops) is not without risk, especially regarding the corneal-conjunctival surface where they may induce a toxic response.