Expanding interest in refractive laser correction renews interest in ortho-K

Issue: September 2001

ByHarue J. Marsden, OD

Orthokeratology (ortho-K) has historically been defined as the programmed replacement of rigid gas-permeable (RGP) contacts to reduce refractive error. The contact lenses are typically flat-fitting RGP lenses, and the fitting philosophy has existed for more than 40 years. With the expanding interest in laser refractive surgery and refractive error modification, ortho-K has experienced a resurgence of interest with the public as well as the contact lens fitters.

Early critics argued that ortho-K results were unpredictable and not permanent. Today, controversy still exists over the practice because of the continued need to wear contact lenses. With this controversy, comes the potential for exaggerating the capabilities of ortho-K. The Federal Trade Commission (FTC) enforces a variety of federal antitrust and consumer protection laws. During the past few years, the FTC has taken action against false claims regarding refractive surgery and ortho-K.

Governmental awareness

This governmental awareness has resulted in the inclusion of ortho-K on the FTC Web site for vision correction procedures: www.ftc.gov/bcp/conline/pubs/health/vision.htm. Additional controversy exists with the regulation of new ortho-K lens designs. It is the responsibility of the Food and Drug Administration (FDA) to evaluate contact lens materials, wear schedule (daily vs. overnight) and contact lens design. This has required contact lens manufacturers to submit data to the FDA for lens material and design for the specific application of ortho-K.

On April 8, 1998, Contex Inc. (Sherman Oaks, Calif.) received the first FDA approval for its OK lens designs in the Airperm material for daily wear ortho-K.

On Sept. 25, 1998, the FDA issued a warning to eye care practitioners, contact lens dispensers and contact lens wearers regarding ortho-K. In the safety report, it states “The safety issues for most daily wear ortho-K lenses have generally been addressed by prior research and review of the one lens cleared for marketing. FDA is not aware of any well-controlled clinical studies published in the literature on the overnight use of ortho-K lenses. The overnight use of lenses is not considered daily wear and is considered extended wear since the lens is worn while the user is asleep.”

The report goes on to state, “An RGP lens designed for ortho-K requires different testing and data than the traditional lens design in order to establish safety and effectiveness. Some finishing labs have assumed — incorrectly — that once the RGP lens material has been cleared for marketing by FDA, they may promote ortho-K lens designs made with that material. This is an illegal practice.” (See www.fda.gov/cdrh/safety/practitioner.htm.)

Industry guidelines

Jim Saviola, OD, FAAO, on behalf of the FDA, published industry guidelines entitled “Guidance for Premarket Submissions of Orthokeratology Rigid Gas Permeable Contact Lenses” on April 10, 2000 (www.fda.gov/cdrh/ode/guidance/1134.html#_Toc476383285). The intent was to provide guidance for contact lens manufacturers when submitting applications for ortho-K devices. Because it is the responsibility of the FDA to protect public health, a large segment of these guidelines relates to labeling and packaging inserts to ensure that reasonable expectations of success are communicated to the user.

The guidance document identifies specific recommendations for a clinical protocol to develop performance data for submitting a daily-wear premarket notification (510K) or an overnight-wear premarket approval (PMA) application for ortho-K. The clinical criteria specified in the guidance document are recommended to adequately demonstrate safety and effectiveness for the intended use of temporary reduction of refractive error.

In addition to labeling suggestions, the guidance document provides sample data reporting tables that are supplemental to the standard contact lens clinical data reporting tables found in the clinical sections of previous contact lens and lens care guidance documents. The FDA considers clinical studies of daily-wear contact lenses to be insignificant risk, whereas studies of overnight-use or extended-wear contact lenses are considered as significant risk investigations.

Several lenses approved

Between 2000 and 2001, Paragon Laboratories (Mesa, Ariz.) received daily wear approval of its ortho-K design in Fluoroperm 60, Fluoroperm HDS and Fluoroperm 151 materials for daily wear. During the same time frame, Polymer Technology (Bausch & Lomb, Rochester, N.Y.) received approval for the Contex ortho-K lens designs in the Boston XO, Boston EO and Boston Equalens II materials for daily wear. Although the current FDA approval for ortho-K is for daily wear only, many contact lens fitters use ortho-K as an overnight program. Some confusion exists regarding the ramifications in clinical practice.

Overnight ortho-K

Due to the potential conflict of interest and confidential nature of investigational clinical trials, there is very little public information available regarding overnight FDA clinical investigation of ortho-K lens designs. A pilot study using the Paragon CRT (corneal refractive therapy) lens is underway as a multicenter clinical trial involving the Ohio State University, New England College of Optometry, Southern College of Optometry, Southern California College of Optometry and University of Missouri, St. Louis. The Longitudinal Overnight Orthokeratology (LOOK) study is designed to determine the success of overnight ortho-K with low myopes, which patient variables predict success and the safety and efficacy of overnight ortho-K.

In July, the Paragon CRT lens was introduced in Toronto on a limited basis with an overnight wear schedule.

Many contact lens fitters have years of experience with overnight ortho-K. Unfortunately, without published, controlled clinical studies, skepticism will exist regarding the success of overnight ortho-K.

Effects on clinical practice

Because there is currently no lens approved for overnight ortho-K by the FDA, what does this mean to the contact lens fitter? The FDA warns, “Contact lens manufacturers and finishing labs who promote the sale of a specific ortho-K lens design to eye care practitioners are subject to regulation by the FDA. The same regulation applies to eye care practitioners who promote ortho-K lenses outside the scope of their own practices — e.g., the marketing and promotion of an unapproved product to other practitioners.”

The Public Health Notification continues by stating that, “A licensed practitioner may individually design and prescribe an RGP ortho-K lens for a particular patient within the scope of his/her practice. However, eye care practitioners who promote ortho-K in their practice should avoid making exaggerated and unsupported claims of safety or effectiveness. Promotional material should include accurate, well-balanced statements explaining that the effect of these lenses is temporary and limited.”

Obtain informed consent

Due to the litigious potential for use of a medical device in an “off-label” application, it is important that patients are properly informed and documented consent is obtained. The basic informed consent form should include a statement and description of the device and procedure. It should include a statement indicating whether or not the device is approved by the FDA for ortho-K and whether the material and design are approved for daily or overnight wear.

Many manufacturers of reverse geometry rigid contact lenses do not have approved ortho-K designs, but the material may be approved for overnight use. The informed consent form should include a description of any benefits or risks to the patient that may reasonably be expected from the procedure. Additionally, the patient should be informed of appropriate alternative procedures or courses of treatment.

Reasonable claims

To avoid the potential for abuse, the contact lens fitter must make reasonable claims regarding the effectiveness and safety of overnight ortho-K. For a patient to completely understand the risks and limitations of ortho-K, the contact lens fitter should educate him or her about all of the options.

It is exciting to see the gaining interest of this refractive error correction procedure. With carefully designed studies, it is hoped that the information obtained will address the concerns and skepticism surrounding ortho-K.

Currently, in the United States, little data exist regarding lenses undergoing FDA clinical investigation for overnight use due to confidentiality restrictions. Data are not generally prematurely published so that public opinion does not influence the approval decision. With a clearer comprehension of governmental process and regulations, the contact lens fitter can understand the issues and concerns of overnight ortho-K.