Rewetting drops and contact solutions are fundamentally different products, serving distinct purposes for contact lens wearers. They differ significantly in their chemical makeup and intended application. Contact solutions are designed for hygiene and storage outside the eye, while rewetting drops are formulated for lubrication while the lens is being worn.
The Primary Function of Contact Lens Care Solutions
Contact lens care solutions are designed for use when the lenses are not in the eye, focusing on cleaning, disinfecting, and storage. These solutions eliminate microorganisms and remove accumulated debris, such as proteins and lipids, that build up during wear. Multi-purpose solutions combine cleaning, rinsing, and disinfecting functions using surfactants and chemical disinfectants to kill pathogens. Hydrogen peroxide systems require a neutralization step before the lenses can be safely placed back in the eye. Inadequate cleaning and disinfection significantly increase the risk of eye infections.
How Rewetting Drops Provide On-Eye Comfort
Rewetting drops are specifically formulated for use while the contact lenses are in the eye. Their primary function is to provide lubrication and moisture to alleviate dryness, minor irritation, or foreign body sensation that occurs during the day. The lens can sometimes disrupt the eye’s natural tear film, making these drops necessary for comfort. They work by temporarily augmenting or stabilizing the tear film on the ocular surface, effectively hydrating the contact lens. These products often utilize simple saline solutions with added viscosity enhancers, such as sodium hyaluronate, and are formulated to be gentle enough for direct application without causing irritation.
Chemical Differences and Consequences of Misuse
The fundamental difference between these two products lies in their active ingredients, which dictates their function and safety profile. Contact solutions contain disinfectants and surfactants designed to kill microbes and strip away protein deposits on the lens. Rewetting drops, conversely, contain mild buffers, electrolytes, and lubricants designed to soothe and moisturize the eye’s living tissue.
Misusing Contact Solution
Confusing a contact solution for a rewetting drop can have adverse consequences. The disinfecting agents in contact solution, such as chemical preservatives or un-neutralized hydrogen peroxide, are too harsh for direct application to the eye. Using a solution as an eye drop can cause irritation, stinging, redness, or inflammation. Over time, this misuse can damage the eye’s natural tear film, potentially leading to chronic dryness.
Misusing Rewetting Drops
Using rewetting drops to clean and store lenses carries a greater risk of infection. Rewetting drops lack the necessary disinfecting and cleaning agents to eliminate pathogens and remove protein buildup. Storing lenses in these drops allows microorganisms to flourish, leading to severe bacterial or fungal growth. This inadequate hygiene significantly raises the risk of serious eye infections, such as microbial keratitis.