Article Date: 8/1/2005

extended wear
What You Need To Know About Extended Wear
Understand all the benefits and risks of these popular contact lenses.
MICHAEL J. LIPSON, O.D., F.A.A.O., Livonia, Mich.

Extended wear (EW) contact lenses are here to stay! The newest of the EW lenses are highly oxygen-permeable and much safer than their predecessors, but it still pays to proceed with caution.

Currently, there are a number of lenses with FDA approval for between six and 30 days of extended or continuous wear. They are generally categorized as soft-hydrogel, silicone-hydrogel and gas-permeable. With a large range of parameters available, and more becoming available every month, extended wear is a viable option for you and your patients.

Why fit extended wear?

First, patients like it! They enjoy the convenience of spending less time on care and handling, along with the pleasure of waking-up to a clearer world. Patients who experience chronic redness from solution reactions or lens deposits may experience fewer red-eye reactions. Others, who frequently damage their lenses during handling, may gain better comfort and longer-lasting lenses. It can also reduce the risk in situations when it may be difficult to handle lenses, like while camping or using public restrooms.

Second, doctors like it! Many of those who are fitting extended wear find they have fewer CL dropouts, less complications and increased patient loyalty. When patients have fewer problems, they continue to wear these lenses and return to the doctor who prescribed them. They also talk to others about these contact lenses that give them clear, comfortable vision.

Not everyone is a candidate for this modality, however. Patients who will likely do well with extended wear are those have a history of compliance and healthy corneas. Patients with chronic allergies, significant dry eye, corneal dystrophy, any corneal pathology (like keratoconus) and some diabetics (due to increased healing time) are generally not good candidates for this wearing schedule.

Patients who upgrade from other lenses to extended wear may show slight Rx changes after the first few weeks of wear. Advise them of this possibility beforehand and schedule follow-up visits sooner than you would for new wearers to monitor for these refractive changes. Having patients discontinue their current lenses for a few days prior to commencing extended wear can also be helpful.

Proceed with caution

Even though some high-Dk lenses are approved for up to 30 days of continuous wear, you, as the prescribing doctor, must determine each patient's wearing schedule individually. Prescribe with safety as your top priority, convenience second. Even with plenty of oxygen transmission, careful follow-up is necessary to assess proper lens fit and movement, the presence of any debris/deposits on or under the lens, keratitis (mechanical or microbial) and possible eyelid reactions. Any patient wearing a lens while sleeping has the potential to get debris trapped between the eye and the lens. Based on observations of the lens and the cornea during initial follow-up visits, establish a safe wear schedule for each patient. According to one study, the incidence of microbial keratitis with extended wear of soft hydrogel lenses was estimated to be one in 500 (a 2004 study estimates about one in 200). Similar studies have projected the incidence of microbial keratitis with silicone/hydrogel extended wear at one in 5000, and with extended wear GP, one in 10,000.

Conduct fitting evaluations at three to four days after the initial fit and again two to three weeks later. Strongly advise patients to report any discomfort, blurred vision or redness immediately for evaluation. Regular follow-up care is just as essential as the wearing/replacement schedule. In our office, we schedule annual exams with a contact lens evaluation every six months after the initial fitting visits. I also advise having a strategy for in-office and specialty referral management of potentially serious complications.

Managing EW

Many patients will wear lenses for the prescribed time period and dispose of the lenses upon removal. Obviously, these patients will not require solutions or a care system for disinfection. For those who do re-use lenses, proper disinfection is crucial. In these cases, stress the importance of hand washing, lid hygiene and exact following of disinfection procedures. Multi-purpose and hydrogen peroxide systems have been found very effective. Re-using a contaminated lens significantly increases the risk of infection with overnight wear. However, gas permeable lenses may periodically need special cleaning or polishing and require regular replacement.

One activity that poses a risk for extended wearers is swimming. A recent study at Pacific University showed water-born bacteria binds to the surface of all soft lenses. The researchers concluded that if patients wear lenses while swimming, they should remove lenses after swimming for a thorough cleaning and disinfection prior to overnight wear. They also advised that patients wear tight-fitting goggles while swimming.

Extended wear gained FDA-approval because it satisfied requirements for oxygen transmission and safety. You are obligated to ensure that each patient is monitored for continuing eye health and as such, must establish a safe wearing schedule for each patient. Once that schedule has been determined, it is imperative that the patient follow it. Hand the patient (or parents if the patient is a minor) a written wearing/disposal schedule and keep a copy in the patient's record. I also include the date and time of their next follow-up appointment written on this sheet. When dispensing lenses, it is important to stress that the next complete vision and contact lens evaluation will be necessary when the prescription for theses lenses expires.

Another tool to help with compliance is an "informed consent form." This is an in-office document explaining what the lenses do, the benefits and risks associated with extended wear, alternative modes of vision correction and the importance of following your recommended wearing, replacement and follow-up schedule. This form should also include emergency contact information of the doctor and office so patients can contact the ECP any time a problem may arise. Have each patient or guardian read and sign the form and include it in their file. Also give a copy to the patient to keep in their records.

The professional expertise involved and the additional time requirements demand that you establish higher professional fitting fees for management of EW. Explain this to patients going into extended wear. Those who want the convenience will appreciate that you are providing a service that they may not have experienced before.

Prescribing extended wear lets your patients know you are working with the latest contact lens technology. It also allows you to market yourself to a new group of potential patients. This creates excitement for patients, while generating referrals and revenue for the practice. As a final reminder, prescribe a safe wearing schedule and monitor with careful follow-up to assure compliance. 

Getting the Most from Extended Wear GPs
Robert M. Grohe, O.D.

Many aphakic patients were among the first contact lens wearers in EW until intraocular lens [IOL] implants gradually replaced the use of PMMA as an extended wear material. Today, modern orthokeratology has expanded the role of GP contact lenses from premium refractive correction among some cosmetic lens wearers, to slowing myopia progression and often reducing/eliminating myopia with corneal refractive therapy.

Here are some benefits for patients and eyecare practitioners when comparing soft with GP contact lenses for extended wear:

1. Hyper-Dk lens materials promote a safer extended wear experience by providing an oxygen-dense environment for the cornea. Recent studies indicate less bacteria bind to the surface of hyper Dk GP lens materials.

2. There is a lower incidence of corneal ulcers and infiltrative keratitis in GPs when compared with soft-lens extended wear, especially for non-silicone based hydrogel designs.

3. Dynamic tear exchange fosters a better back-lens and surface/cornea (retro-lens) environment.

4. Using therapeutic agents to treat chronic diseases such as ocular allergies or glaucoma is extremely easy.

5. Because non-damaging fluorescein is used in evaluating corneal response to extended wear, the safety of the physiologic assessment is improved.

6. GP laboratories have passed high quality inspection standards, while implementing advanced manufacturing techniques that enable better physical durability of lens materials.

7. Multiple lens parameters are available to be customized and/or produced in-house. Contact Lens Manufacturing Association (CLMA)-member laboratory consultants can also help with designs. And, fitting resources are also available through the GP Lens Institute (GPLI) at: www.gpli.info.

8. Vision is clear, consistent and precise, even with prolonged GP extended wear.

9. GP lenses have a longer life with one-pair convenience. GP lens materials are able to withstand one to two years of routine lens wear and handling.

10. With the addition of deposit-resistant fluorine to recent GP polymers, they now require less cleaning, as the surfaces remain more resistant to long-term deposit buildup.

Dr. Grohe is in private practice in Homewood, Ill. and Northwestern University Medical School, Ophthalmology Department in Chicago and serves on the Gas Permeable Lens Institute's Advisory Committee.

 

Follow-up Care for GP Lenses
Robert M. Grohe, O.D.

Concerns when using GPs for extended wear generally include monitoring for vascularization, excessive corneal flattening, lens adhesion, corneal warpage and hyper-DK mishandling. Using corneal topography to monitor for subtle, localized corneal distortion or warpage can reduce the risk for complication. At each contact lens office visit, watch for any emerging signs of lens adhesion or decentration, which would indicate the need to refit due to a probable change in lens- and or corneal-curvature.

Complications can be dramatically reduced when patients comply with regular follow-up care. Maintaining a safe patient wearing experience typically calls for seven to 30 days of maximum lens wearing at one time. In between visits, instruct patients to use a conditioning and cleaning solution, along with overnight enzyme soaking prior to reinsertion in the morning. Educate the patient about lens cleaning and handling techniques for hyper-Dk GPs in the evening using the palm of the hand with the fifth finger in a back and forth motion.

Since computer users are at greater risk for dryness and redness, advise that they break the gaze cycle by looking away from the monitor every 15-30 minutes and try to consciously blink 15-20 times per minute when staring at the monitor. Some occupational concerns will preclude patients for GP wear, including those exposed to high levels of dust, chemicals, organic solvents or construction work.

Dr. Lipson is a clinical instructor with the Department of Ophthalmology and Visual Sciences, Medical School, Kellogg Eye Center at the University of Michigan. His clinical practice focuses on primary care and specializes in contact lenses.



Optometric Management, Issue: August 2005