When Should You Change Your Contact Lenses?

Why Wearing Contacts Beyond Their Schedule Can Be Risky

A contact lens may not look noticeably different when its replacement date arrives. However, deposits, microorganisms, and gradual changes to the lens material can still affect how safely and effectively it performs.

Even a lens that feels comfortable may no longer provide the same smooth surface, moisture retention, or oxygen transmission it offered when new. Potential consequences of wearing contacts longer than directed include:

Eye Irritation and Discomfort: Proteins and oils from your tears can collect on reusable lenses along with dust, pollen, makeup, and environmental debris. This buildup can make the lens surface feel rougher and less comfortable. Over time, you may notice burning, itching, dryness, or a gritty sensation, especially near the end of the day.
Blurred or Cloudy Vision: Deposits can make contacts appear cloudy and interfere with clear sight. Lenses may also develop small scratches, tears, or changes in shape as they age. These imperfections can cause hazy or fluctuating vision and make tasks such as reading, driving, or working at a computer more difficult.
Increased Risk of Eye Infections: Bacteria, fungi, and other microorganisms can accumulate on contact lenses and in storage cases. The longer a pair is used, the more opportunity these organisms have to remain on the lens surface. This can increase the risk of infections such as keratitis, which may cause redness, pain, discharge, light sensitivity, and corneal damage when not treated promptly
Reduced Oxygen Supply to the Eyes: Your cornea receives oxygen from the surrounding air. Contact lenses are designed to allow oxygen to pass through to the eye, but deposits and material deterioration may make older lenses less breathable. Reduced oxygen exposure can contribute to corneal hypoxia, which may lead to swelling, redness, irritation, and other complications.
Corneal Ulcers and Long-Term Damage: Severe infection or inflammation may occasionally cause a corneal ulcer, which is an open sore on the eye’s surface. Symptoms can include significant pain, discharge, extreme light sensitivity, and reduced vision. Corneal ulcers require prompt treatment and may result in scarring or permanent vision loss. Although uncommon, they are more likely when contacts are overworn, slept in improperly, or handled without appropriate hygiene.

Understanding Contact Lens Replacement Schedules

Contact lenses are manufactured with different materials and wearing schedules. The correct replacement timeline is determined by the design of the lens and should not be extended based on convenience or how often you choose to wear it.

Single-Use Disposable Lenses

Single-use lenses, sometimes called daily disposable lenses, are designed to be worn once and discarded immediately after removal. Each day begins with a clean, sterile pair, so there is no need to use cleaning solution or store the lenses overnight.

Daily lenses may be especially convenient for occasional contact lens wearers, people with active schedules, travelers, and those who want to avoid maintaining a storage case. Wearing a fresh pair every day also reduces the opportunity for proteins, oils, allergens, and microorganisms to accumulate on the surface. Single-use lenses have been associated with substantially fewer adverse effects than reusable contact lenses. However, you should never save a daily disposable lens for another day. Once it has been removed from your eye, throw it away, even if it was only worn for a short period.

Biweekly Disposable Lenses

Biweekly contact lenses are generally intended to be replaced 14 calendar days after the package is opened. After each wear, they must be removed, cleaned, disinfected, and stored in an appropriate contact lens case filled with fresh solution.

These lenses can be a useful option for people who prefer reusable contacts but want a shorter replacement schedule than monthly lenses. When they are maintained properly, replacing them every two weeks can help limit the amount of deposit buildup that forms on the surface.

The 14-day timeline usually begins when you open the package, not each time you wear the lenses. If you use the pair only a few times during those two weeks, you generally should not continue wearing it beyond the scheduled replacement date.

Monthly Disposable Lenses

Monthly contacts are designed to be reused for approximately 30 days after opening. They may offer a convenient and cost-effective option for regular contact lens wearers, but they require consistent cleaning, disinfecting, and storage.

Each time monthly lenses are removed, they should be rubbed and rinsed with the recommended contact solution before being placed in a clean case containing fresh disinfecting solution. Proper care can help them remain comfortable throughout the month, but it does not extend their approved lifespan.

Discard monthly contacts when their 30-day replacement period ends. Continuing to use them for additional days or weeks may increase deposit buildup, contamination, discomfort, and changes in vision.

Extended Wear Lenses

Extended wear lenses are made from highly breathable materials and may be approved for continuous wear, including overnight use, for a limited period. Depending on the specific product and prescription, this may range from several nights to a few weeks.

Even when a lens has been approved for overnight wear, sleeping in contacts carries a higher infection risk than removing them before bed. Closing your eyes reduces oxygen exposure and creates an environment in which microorganisms may remain trapped against the cornea for an extended period. Do not sleep in contacts unless an optometrist has confirmed that your particular lenses and wearing schedule are appropriate for your eyes. Follow the prescribed removal and replacement instructions carefully. Wearing extended wear lenses longer than directed may lead to inflammation, infection, or corneal ulcers.

Are Replacement Schedules Based on Calendar Days or Times Worn?

Most reusable contact lens schedules are measured from the day the package is opened rather than by the number of times the lenses are actually worn. For instance, a two-week lens typically needs to be discarded 14 days after opening. Wearing that pair only on weekends does not necessarily mean it can be used for several months.

Monthly contacts generally follow the same principle. After a lens is removed from its sterile package, it is exposed to handling, cleaning products, storage conditions, microorganisms, and gradual changes in the material. These changes may occur even on days when the lens remains in its case.

Do not rely only on how the contacts feel. A lens may still seem comfortable after its approved replacement period has ended. Follow the instructions for your exact lens brand and material, along with the schedule provided by your eye doctor. To keep track, write down the date you open each pair or set a recurring reminder on your phone. People who frequently lose track of reusable lens schedules may want to ask whether daily disposable contacts would be a more convenient option.

When to Replace Your Contact Lenses Early

Your scheduled replacement date represents the longest a contact lens should generally be used under normal conditions. A lens should be thrown away sooner if it becomes damaged, contaminated, uncomfortable, or associated with unusual symptoms.

Signs that you may need a fresh pair include:

Discomfort or Irritation: A contact that feels dry, scratchy, itchy, or gritty may have excessive deposits or damage to its surface. Remove the lens rather than continuing to tolerate the irritation. If a new pair feels comfortable, the previous lens may have been the problem.
Blurry or Cloudy Vision: Protein buildup, cosmetics, scratches, or small tears may prevent a contact from providing clear sight. If blinking or using an approved contact lens rewetting drop does not restore your vision, remove and replace the lens.
Redness or Swelling: Red or swollen eyes can be a sign of dryness, inflammation, an allergic response, or infection. Take your lenses out immediately and avoid inserting another pair while your eyes remain red or uncomfortable.
Visible Damage to the Lenses: Inspect each contact before insertion. Discard it if you see a tear, crack, chip, rough edge, or warped area. A damaged lens may scratch the eye’s surface or become caught beneath the eyelid.

How to Properly Care for Reusable Lenses

Reusable contacts must be cleaned, disinfected, stored, and handled correctly every time they are removed. Proper care does not allow lenses to be worn past their approved replacement date, but it can help them remain safe and comfortable throughout the prescribed period.

Clean Your Lenses Thoroughly: Each time you remove your reusable lenses, gently rub them with contact solution to remove any buildup of proteins, dirt, and debris. Never use water or saliva to clean your lenses, as these can introduce harmful bacteria that could lead to infections.
Store Contact Lenses in a Case: Whenever you’re not wearing your contacts, store them in a clean, sterile case filled with fresh contact solution. Never reuse old solution, as this can allow bacteria to grow in the case and contaminate your lenses. It’s also essential to replace your lens case every few months to further reduce the risk of contamination.
Wash Your Hands Before Handling Lenses: Before touching your lenses, always wash your hands with soap and water to minimize the risk of transferring dirt or bacteria to your eyes. Avoid using moisturizing soaps or lotions before handling your lenses, as residue from these products can stick to the lenses and cause irritation.
Follow the Manufacturer’s Guidelines: Because different lenses have different care instructions, always follow the guidelines provided by your optometrists and/or the lens manufacturer. This includes using the correct type of contact solution, cleaning method, and storage practices.
Avoid Overwearing Contact Lenses: Overwearing your lenses can lead to a buildup of deposits, reduced oxygen flow to the eyes, and increased risk of irritation or infection. Stick to your lens replacement schedule, and if your lenses start to feel uncomfortable before the replacement date, it’s better to switch to a fresh pair early.