What common preservative found in gas permeable solutions may cause eye irritation?

Benzalkonium Chloride is a common preservative used in gas permeable contact lens solutions. It is known for its antimicrobial properties, making it effective in preventing the growth of bacteria and other microorganisms in the solution. However, one of the notable side effects of this preservative is that it can cause eye irritation in some individuals. This irritation can manifest as redness, burning, or a gritty sensation in the eye upon application of the solution.

Other preservatives, such as ethanol or chlorhexidine, do have their own interactions with the eye, but benzalkonium chloride is specifically recognized in the context of contact lens solutions for its potential to produce discomfort. Sodium hydroxide, while it can be caustic, is primarily used to adjust the pH of solutions and is not typically associated directly with irritation from solutions designed for contact lenses in the same way that benzalkonium chloride is. Thus, while all options may have specific applications or effects, benzalkonium chloride stands out as the most relevant preservative associated with eye irritation in gas permeable solutions.