by Dr. Melody Huang

Contact lens wearing schedules (also called wear modality) refer to how long a person can keep a contact lens in the eye and how long they can keep the same lens.

When working with patients who use contact lenses, a frequently heard comment is, “I keep the same pair of contact lenses longer than I’m supposed to.” Patients have many reasons for not adhering to a contact lens wearing schedule, and it’s up to their eye care team to help them understand why it’s essential to do so.

Types of contact lenses

Contact lens wearing schedules are classified in the following ways1:

  • Extended wear

  • Daily Wear

  • Daily Disposable

  • Frequent or planned replacement

  • Conventional

Here are some key points to know about wearing schedules1:

  • The FDA doesn’t specify how many times a contact lens can be used or how often it should be replaced. Instead, the manufacturer sets a recommended replacement schedule for their contact lenses. The Eye Care Practitioner then decides on the best replacement schedule for the patient.
  • The FDA defines daily disposable lenses as contacts that are used once, then thrown away. Many contact lens vendors and Eye Care Practitioners refer to frequent/planned replacement lenses as disposable, which might cause some confusion since frequent/planned replacement lenses are used more than once.
  • Wear schedules begin when the lens packaging is opened, regardless of how often the patient uses them. For example, if the patient has a monthly lens but only wears contacts twice a week, they should still dispose of the contacts at the end of the month instead of keeping them longer.

Extended wear contacts

Extended wear (EW) contact lenses are generally approved for up to 6 nights (7 days) of overnight wear before removal1, with one night of rest without contact lenses in between pairs2.

Typically, most EW contacts are made of silicone hydrogel, since this material allows more oxygen to reach the eye than conventional hydrogel material1. This feature is important because sleeping in contact lenses reduces the amount of oxygen to your cornea (corneal hypoxia)3. Corneal hypoxia can lead to complications such as decreased corneal sensation, abnormal blood vessel growth, and corneal swelling3. These problems can affect the wearer’s vision and ability to use contact lenses.

Since there is a higher risk for EW contact lens complications4, the Eye Care Practitioner can determine if a patient is eligible for EW contacts based on their eye health and contact lens wear compliance. Some patients depend on EW contacts for their occupation, such as military personnel, first responders, or anyone who needs clear vision at any given moment.

Extended wear lenses include:

  • Biofinity®
  • Air Optix®Aqua with Hydraglyde®
  • Air Optix® Night & Day®  (CW)
  • PureVision®
  • PureVision® 2
  • Ultra®
  • Acuvue® Oasys®  with Hydraclear® Plus

Daily wear contacts

Unlike EW lenses, daily wear (DW) contacts are designed for use while awake and removed before sleep1. DW lenses are available in both conventional hydrogel and silicone hydrogel materials5. Depending on the material, DW contacts are categorized into monthly, two-week, and daily replacement schedules1.

Monthly replacement

As the name suggests, the wearer can use one pair of these contacts for up to one month. In between uses, the wearer must clean and disinfect the lenses with contact lens solution.

After a month, the contacts should be replaced with a new pair.

A yearly supply costs approximately $150 to $2506. Although monthly contacts seem the most cost-effective since the patient buys a smaller quantity of lenses, they should keep in mind that contact lens solution and cases can add about $200 to the overall cost7.

Monthly replacement lenses include:

  • Biofinity®
  • Proclear®
  • Air Optix®Aqua with Hydraglyde®
  • PureVision®
  • PureVision® 2
  • Ultra®
  • Acuvue® Vita®

Two-week replacement

These lenses can be used for up to two weeks. Like monthly replacement lenses, the wearer cleans and disinfects the lenses each night before using the next morning. Two-week lenses cost a bit more than monthly lenses because the wearer needs a larger quantity of contacts. A typical range for a yearly supply is $200 to $3006. The cost of contact lens solution and cases also applies to two-week replacement lenses.

Two-week replacement lenses include:

Daily disposable

According to the FDA, disposable lenses are used once, then thrown away1. However, some Eye Care Practitioners call any lens used for a month or less “disposable.” To avoid confusion, many manufacturers add “daily” or “one day” to the name of their daily disposable lenses. Also, daily disposable contacts should not be confused with the term “daily wear.”

Daily disposables offer many benefits, including improved lens hygiene, better comfort, convenience, fewer deposits, less need for solution, and availability of spare lenses1. A yearly supply of daily lenses costs around $400 to $6005. Many patients are concerned with the cost of daily disposables. Because the cost of the solution is eliminated, the price difference is not as significant when compared with monthly or two-week lenses.

Daily disposable lenses include:

  • clariti®
  • MyDay®
  • Proclear® 1 Day
  • Biotrue® ONEday
  • Infuse®
  • SofLens® Daily Disposable
  • Dailies Total 1®
  • Precision 1®
  • DAILIES®  AquaComfort Plus®
  • Acuvue® Oasys® 1 Day with HydraLuxe™
  • 1-Day Acuvue® Moist
  • 1-Day Acuvue® TruEye®

Frequent or planned replacement

These include lenses that are replaced every two weeks, one month, three months, six months, or any time in between1. Surveys show that 97% of soft contacts prescribed in 2019 were either daily, two-week, or monthly replacement lenses, while only 3% were 3 to 6-month replacement lenses8.

Conventional lenses

These contacts usually come in vials and are replaced every 6 months to one year. Surveys show that only 1% of soft contacts prescribed in 2019 were yearly replacement lenses8. Some manufacturers have discontinued their conventional lenses as disposable and frequent replacement lenses have increased in popularity among Eye Care Practitioners1 and increased parameter availability in frequent replacement lenses, such as the extended range Biofinity contact lenses.

Importance of contact lens compliance

A compliant contact lens patient is someone who properly cleans, handles, and wears their contacts9. A significant portion of lens compliance is adhering to the wearing schedule set by the Eye Care Practitioner. However, studies estimate that only 1% to 50% of patients are truly compliant with contact lens wear10. Some reasons for low compliance rates include saving money and forgetting the correct lens replacement schedule10.

Failing to follow the recommended replacement schedule can cause problems such as:

  • Increased lipid and protein deposits1
  • Blurry vision1
  • Poor comfort1
  • Lens tears or nicks1
  • Inflammation or infection10

Here are some tips to help patients increase their compliance:

  • Switch to daily disposables. Studies find that daily disposable wearers are more likely to replace their lenses on schedule9.
  • Switch from two-week to monthly lenses if daily disposables are not feasible. Two-week lens wearers are more likely to stretch their replacement schedules than monthly lens wearers11. If patients cannot keep track of how long they are wearing their two-week lenses, a monthly replacement schedule may be easier for them to remember. For example, they can start a new pair on the first of the month and dispose of them on the last day of the month.
  • Hand out written instructions along with verbal instructions on contact lens wear. A written guide with illustrations increases compliance better than verbal instructions alone10.

Financial implications

Besides health, comfort, and vision concerns, there are financial reasons why an eye care team should ensure patients follow their recommendations for wearing schedules.

Studies show that the most compliant patients12:

  • Purchase an annual supply of contacts
  • Are more likely to wear daily disposables (or monthly replacement lenses)
  • Return more frequently for eye exams

All of these factors can have a significant impact on your practice’s income! Educating patients on contact lens compliance is a win-win for everyone involved. Patients maintain healthy eyes and clear vision, while Eye Care Practitioners ensure their contact lens practice is profitable!

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Sources

  1. Vinita Allee Henry, Steve Diamanti & Julie Ott DeKinder (2020), ”Soft Material Selection (Hydrogel & Silicone Hydrogel)” in Clinical Manual of Contact Lenses, 5th Ed., Eds. Ed Bennett and Vinita Henry, China: Wolters Kluwer, pp. 288-310.

  2. Types of Contact Lenses. U.S. Food and Drug Administration. https://www.fda.gov/medical-devices/contact-lenses/types-contact-lenses.

  3. Chalmers et al IOVS 2011; 2. Chalmers et al Optom Vis Sci 2012

  4. Liesegang, TJ. Physiologic Changes of the Cornea with Contact Lens Wear. CLAO J. 2002;28(1):12-27.

  5. ODspecs. ODspecs.com. http://www.odspecs.com/.

  6. Cost of Contacts in 2020: How Expensive Are They? NVISION Eye Centers. https://www.nvisioncenters.com/contacts/costs/.

  7. Heiting G. How Much Do Contacts Cost? All About Vision. https://www.allaboutvision.com/contacts/faq/contact-cost.htm. Published August 25, 2020.

  8. Morgan PB, Woods CA, Tranoudis IG, et al. International Contact Lens Prescribing in 2019. Contact Lens Spectrum. https://www.clspectrum.com/issues/2020/january-2020/international-contact-lens-prescribing-in-2019.

  9. Pucker AD. Contact Lens Care and Compliance: An Update. Contact Lens Spectrum. https://www.clspectrum.com/issues/2016/november-2016/contact-lens-care-and-compliance-an-update.

  10. Steele K. Contact Lens Compliance: A Review. Contact Lens Update. https://contactlensupdate.com/2018/10/26/contact-lens-compliance-a-review/

  11. Dumbleton KA, Woods CA, Jones LW, et al. The relationship between compliance with lens replacement and contact lens-related problems in silicone hydrogel wearers. Contact Lens and Anterior Eye. 2011;34(5):216-222.

  12. Dumbleton K, Richter D, Bergenske P, et al. Compliance with lens replacement and the interval between eye examinations. Optometry and Vision Science. 2013 Apr;90(4):351-358.

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