Contact lenses are a widely used vision correction method, but the variety of available replacement schedules often creates confusion for new wearers. Reusable options do exist, and understanding the precise difference between reusable and disposable lenses is paramount for maintaining eye health. The intended replacement schedule of a lens dictates the required care routine, which ultimately determines how often a lens must be discarded.
Defining Reusable and Disposable Contact Lenses
The primary distinction between different types of soft contact lenses centers on their intended lifespan and replacement cycle. Daily disposable lenses, also called single-use lenses, are designed to be worn for a single day and then immediately thrown away before sleep. This design offers maximum convenience and eliminates the need for cleaning or storage products. In contrast, reusable lenses, sometimes called planned replacement lenses, are meant to be cleaned and stored each night and worn multiple times before they are discarded. These lenses typically follow a bi-weekly (14-day) or monthly (30-day) replacement schedule, depending on the specific brand and material. Although they offer a more cost-effective option than daily disposables, this benefit is directly tied to a mandatory daily maintenance routine.
The Necessity of Daily Cleaning and Storage
The ability to reuse a contact lens is conditional upon a rigorous and consistent cleaning process performed every time the lenses are removed. This routine begins with thoroughly washing and drying hands with a lint-free towel before touching the lenses or case. Lenses must be cleaned using the “rub and rinse” method, which involves placing the lens in the palm, applying multipurpose solution, and gently rubbing the lens surface with a clean finger. Even if a multipurpose solution is labeled as “no-rub,” this manual action is recommended to dislodge protein deposits and debris that naturally accumulate on the lens surface. After rubbing, the lens should be rinsed with fresh solution before being placed into a clean case filled with new disinfecting solution for overnight storage. This nightly soaking period is necessary for the solution to effectively disinfect the lens and prepare it for safe wear the next day.
Understanding Extended Wear Lenses
A specific category of reusable lenses is known as extended wear (EW) lenses, which are designed to be worn continuously, including while sleeping, for a defined period. Modern EW lenses are often made from silicone hydrogel, a material engineered to allow significantly more oxygen to pass through to the cornea than previous soft lenses. This increased oxygen permeability is necessary because the closed eyelid environment during sleep naturally limits the cornea’s oxygen supply. Depending on the lens brand and the eye doctor’s recommendation, these lenses may be approved for continuous wear for up to seven days and six nights, or even up to 30 days. However, wearing any contact lens overnight carries an increased risk of eye infection, so an eye care professional must determine if a patient’s eyes are suitable for this type of continuous wear.
Preventing Contamination and Eye Health Risks
Mishandling reusable contact lenses can introduce harmful microorganisms to the eye, leading to serious infections like microbial keratitis. One of the most significant contamination risks comes from exposing lenses to water, including tap water, which can harbor pathogens such as Acanthamoeba. Contact lenses should never be rinsed or stored in water or saliva, as these are not sterile and can cause severe eye problems. Another common mistake is “topping off” the solution, which means adding fresh solution to the old, used solution already in the case. This practice dilutes the disinfectant, reducing its effectiveness and allowing bacteria to thrive. The lens case itself must be maintained; it should be rinsed with solution, air-dried upside down after each use, and replaced entirely at least every three months to prevent it from becoming a source of contamination. Misusing lenses, such as wearing them past their replacement date, also causes a buildup of protein and lipid deposits that can lead to corneal irritation or inflammation.