Contact lenses are medical devices sealed in plastic blister packs, submerged in a sterile, buffered saline solution. Proper storage of these unopened packages is necessary to maintain guaranteed sterility and the integrity of the lens material. Neglecting storage guidelines can compromise the lens, potentially leading to discomfort or serious eye health issues upon insertion.
Understanding the Expiration Date
The expiration date marked on the contact lens box or individual foil blister pack is a precise guarantee from the manufacturer. This date signifies the final day the product is certified to be sterile and effective. It is a common misconception that this date relates solely to the lens material. The expiration is more directly tied to the stability of the sterile saline solution and the long-term integrity of the package’s hermetic seal. Over many years, the balanced saline solution can degrade, potentially losing its ability to keep the lens hydrated and pristine. Using lenses past this date risks introducing contaminants because the manufacturer can no longer ensure the environment is fully sterile, which significantly raises the risk of infections like bacterial keratitis.
Maintaining the Proper Environment
The storage environment must be carefully controlled to prevent damage to both the packaging and the contents. Temperature extremes are a primary concern, as they directly impact the saline solution and the polymer material of the lens. The safest practice is to store boxes in a cool, dry place, generally aligning with typical room temperature conditions. Avoid locations exposed to high heat, such as near radiators, in sunny windows, or inside a car glove compartment. Conversely, freezing the solution may stress the packaging seal. Keeping lenses out of high-humidity areas, like steamy bathroom cabinets, is also wise, as persistent moisture can slowly degrade the adhesive seals on the cardboard box or the foil top of the blister pack.
Ensuring Package Integrity
Any physical damage to the packaging voids the guarantee of sterility, regardless of the expiration date or temperature. Blister packs are designed to be hermetically sealed, meaning they are completely airtight to maintain the sterile environment inside. You must prevent the box from being crushed and the individual foil tops from being punctured or torn. A small tear or crease in the foil seal allows air and potential microorganisms to enter the saline solution, compromising the lens. If a blister pack is punctured, crushed, or the seal appears broken, the lens must be discarded immediately.