Storing contact lenses in eye drops is a dangerous practice that can compromise eye health. When contact lens solution runs out, it can be tempting to use the nearest clear liquid, but eye drops are not a safe substitute for a dedicated lens care product. These two liquids are formulated for entirely different purposes, and substituting one for the other can lead to serious microbial infections and physical damage to the eye.
How Contact Lens Solutions Differ from Eye Drops
Contact lens solutions are engineered specifically to clean, disinfect, and properly store the lens material outside of the eye. These solutions contain active ingredients, such as chemical disinfectants or hydrogen peroxide systems, which are designed to kill harmful microorganisms and prevent bacterial proliferation during overnight storage. Multipurpose solutions also include surfactants that actively remove protein deposits, lipids, and debris that accumulate on the lens surface throughout the day. The primary function is to sterilize the lens, preparing it for safe reinsertion.
Eye drops are formulated only to provide temporary lubrication and moisture directly to the ocular surface. They contain moisturizing agents like carboxymethylcellulose or hyaluronic acid to mimic the eye’s natural tears and relieve dryness or irritation. Eye drops lack the necessary disinfecting and cleaning agents required to sanitize a contact lens.
Proper storage requires a solution with a carefully balanced pH and tonicity to maintain the lens’s shape and hydration. Contact lens solutions are isotonic, which prevents the lens from swelling or shrinking. Eye drops do not provide the necessary chemical environment for long-term lens stability, meaning the lens is neither cleaned nor stored correctly.
Health Risks of Storing Lenses Incorrectly
The primary risk of storing lenses in eye drops or any non-disinfecting liquid is rapid bacterial growth. Eye drops and water do not contain the antimicrobial agents needed to eliminate pathogens, allowing bacteria and fungi to multiply quickly on the lens surface. This microbial proliferation increases the risk of eye infections, particularly microbial keratitis.
Microbial keratitis is a painful and potentially blinding infection of the cornea, often caused by organisms like Pseudomonas aeruginosa or Acanthamoeba that are present in non-sterile water or solutions. Storing lenses in tap water is particularly dangerous because water sources often harbor these organisms. The infected lens then transfers these pathogens directly onto the delicate corneal tissue upon reinsertion.
Improper storage also affects the physical integrity of the contact lens itself. Lenses stored in liquids with incorrect tonicity, such as plain water or some eye drops, can absorb or lose water, causing them to swell, warp, or adhere to the eye. Reinserting a damaged or improperly hydrated lens can cause micro-abrasions on the corneal surface, creating entry points for the bacteria that have multiplied on the uncleaned lens.
Guidelines for Safe Contact Lens Care
If there is an emergency shortage of solution, remove the lenses and store them in a clean, dry case until a proper contact lens solution can be acquired. Never attempt to use water, saliva, or any type of eye drop product as a substitute for disinfection and storage. Only use fresh, FDA-approved contact lens solution, such as a multipurpose solution or a hydrogen peroxide-based system.
Proper contact lens care requires a commitment to strict hygiene, starting with the storage case. Always empty the case completely after removing the lenses, rinse it with fresh solution, and allow it to air dry upside down with the caps off. The contact lens case itself must be replaced at least every three months to minimize the buildup of infectious biofilms.
When cleaning, avoid the mistake of “topping off” old solution with new solution. This practice dilutes the disinfectant’s effectiveness and reintroduces contaminants.