Contact lens solution and eye drops are distinct products formulated for entirely different purposes relating to eye health and lens maintenance. While both liquids interact safely with the eye, they contain different chemical agents. They should never be used interchangeably for the storage or cleaning of contact lenses, as relying on eye drops as a substitute can lead to significant health risks.
Understanding the Purpose of Contact Lens Solution
Contact lens solutions, particularly multi-purpose solutions, perform several functions for the proper care of reusable lenses. Their primary role is to clean the lens surface using compounds like surfactants and sequestering agents. These ingredients work to lift and remove deposits such as proteins and lipids that naturally build up from tears during the day.
A second function is disinfection, which involves killing harmful microorganisms like bacteria, fungi, and protozoa that can contaminate the lenses. Disinfecting agents, such as polyquaternium-1 or polyaminopropyl biguanide, are included to prevent serious eye infections. Without proper disinfection, these microbes can multiply and potentially cause conditions like microbial keratitis.
The solution also serves to store and condition the lenses, ensuring they remain hydrated and maintain their shape and flexibility. Wetting agents and buffers keep the lens material moist and pH-balanced, making the lenses comfortable when inserted. Contact solutions are complex formulations designed to support the integrity of the lens and the health of the cornea.
Why Eye Drops Are Not a Substitute
The difference between eye drops and contact solutions lies in their chemical composition and intended function. Eye drops, also known as artificial tears, are primarily sterile saline solutions containing lubricating agents designed to moisten the eye or the lens while it is being worn. They provide temporary relief from dryness or irritation, but they lack the necessary disinfecting agents and surfactants found in contact lens solutions.
Using eye drops to store lenses overnight increases the risk of serious eye infections. Since eye drops do not contain disinfectants, they fail to kill the bacteria and other pathogens that accumulate on the lens surface during wear. This allows microorganisms to thrive in the lens case, which can lead to severe conditions like bacterial keratitis.
Many eye drops contain thickeners or preservatives that are not intended for long-term contact with the lens material. These ingredients can adhere to the lens, causing a residue buildup that may reduce clarity or lead to irritation when the lens is reinserted. Certain eye drops can also cause the lens material to warp or dry out, potentially damaging the lens permanently and making it unsafe to wear.
Emergency Steps When Contact Solution Is Unavailable
If you find yourself without contact lens solution, the safest step is to avoid using any substitutes for storage. Never attempt to use tap water, bottled water, or saliva, as these contain various bacteria and parasites, including Acanthamoeba, which can cause a serious eye infection.
If the lenses are daily disposables, discard them immediately. For reusable lenses, if no proper solution is available, the lens should be removed and stored dry in a clean case until a proper solution can be purchased. If sterile saline solution is available, it can be used to keep the lenses moist for a short period, but saline only rinses and hydrates; it does not clean or disinfect.
The priority should be to locate a pharmacy, convenience store, or other retailer that sells proper contact lens solution. Once the correct solution is obtained, the lenses must be thoroughly cleaned, rubbed, and soaked in the disinfectant solution for the minimum recommended time before they are worn again. This ensures that any microbes introduced during the emergency are neutralized.