RGPs and Myopia Progression in
Bennett, O.D., M.S.E.d.
A panel of practitioners discusses children and myopia progression.
Renewed interest in orthokeratology, complemented by ongoing clinical research studies on the progression of myopia in young people wearing rigid gas permeable (RGP) lenses, have spotlighted RGP lenses as a viable option for reducing present and/or future myopic refractive error. As the results of these studies become public, with the likelihood that some reduction in myopic progression will result from RGP lens wear, consumers will exhibit more interest in this modality for their children. Practitioners should be prepared for their questions and to fit them appropriately.
Ed Bennett, OD, MSEd, Executive Director of the RGP Lens Institute, questioned four qualified individuals about their opinions on this topic: Joe Yager, OD; Tom Quinn, OD, MS; John Rinehart, OD; and Jeff Walline, OD, MS.
Dr. Ed Bennett: Do you feel, based upon your clinical experience, that RGPs are effective in slowing the progression of myopia in young people? What about soft lenses?
Dr. John Rinehart: For me it is obvious, clinically, that RGPs are very effective in slowing the progression of myopia. Time and time again I find that young RGP wearers' myopia becomes stable. The frequency is far too great to be coincidence. By contrast, I consistently find my young soft lens wearers become more myopic and/or show an increase in with-the-rule astigmatism.
Dr. Jeff Walline: I believe RGPs may slow the progression of myopia, but not in all subjects. We are not sure how rigid contact lenses affect myopia progression, so we don't know what patients they will affect the most. I don't know of any evidence that shows that soft contact lenses slow the progression of myopia.
Dr. Joe Yager: I feel RGPs do indeed slow the progression of myopia. Our office has a history of fitting RGPs and PMMA lenses, and it is very common for 10- to 15-year wearers of rigid lenses to comment that their vision has not changed since they got their lenses. I don't feel that soft lenses slow progression of myopia at all, and in the case of overnight wear, I think they may actually increase the progression.
Dr. Bennett: At what age do you begin to fit myopic patients into contact lenses? Approximately what percentage of these do you fit into RGPs?
Dr. Yager: I fit higher amounts of myopia with RGPs at an earlier age, likewise with faster progressing myopia. I rarely fit a child under 8 years of age, and the youngest I have fit is 6 years of age. I fit about 75 percent of children and teenagers with RGPs.
Dr. Rinehart: I feel very comfortable fitting children 8 years of age. Under the proper circumstances, such as a mature, responsible patient with responsible, supportive patients, I would not hesitate to fit a 5-year-old. While I wish all of my young patients could be fit with RGPs, the reality is that I fit approximately 75 to 80 percent of my patients with RGPs.
Dr. Tom Quinn: I base this decision more on patient maturity and hygiene habits, both of which I assess with parent input. This typically means the middle school years (age 12 or 13), but can be as low as 10 and as high as 16.
Dr. Walline: I begin fitting children at 8 years of age. Some children would be able to adapt to contact lens wear and care for the lenses at an earlier age, but 8 years is typically the minimum.
Dr. Bennett: How do you present RGPs to parents and young patients?
Dr. Rinehart: I talk with patients (the parents are in the room) from the beginning of the presentation, even the very young patient. I want them to know that they play an integral role in the contact lens fitting and wearing process, and they should be a part of the decision-making process. I usually explain the increase in myopia and demonstrate the improved acuity with RGPs. Second, I mention that soft contact lenses may be an option. This option may provide good quality vision, but does not have any therapeutic benefit. Third, I present RGPs to the patient and parents. I explain that this option can actually slow the progression of the myopia and, if we want to be a little more aggressive with the design, it is possible to reduce the myopia. I explain that because the RGP lens has its own rigid shape, I can design the lens such that it will influence the shape of the cornea. A soft lens does not have enough body for this benefit. I briefly explain that by influencing the shape of the cornea, the progression of myopia is, at minimum, slowed. I inform the patient that I have seen fewer health problems with RGPs than with soft lenses, especially with long-term contact lens wear.
Dr. Quinn: I outline the benefits: ease of care, lots of oxygen to the eye (which I explain is necessary to keep the eye healthy), may slow or stop myopic progression, will correct astigmatism (if applicable). I further explain there will be some initial lens awareness, similar to the awareness experienced when wearing a watch or a ring for the first time, that goes away after the first few days.
Dr. Bennett: Approximately what percentage of your young patients successfully adapt to RGPs?
Dr. Walline: Some 75 to 80 percent of young patients successfully adapt to RGPs after one month. There are a few who decide not to wear them after the novelty wears off (three to six months later).
Dr. Rinehart: My best estimate would be that 90 percent of the young people fit with RGPs successfully adapt. I recently had a mother come in and tell me that two to three years after we had fit her daughter with RGPs, the daughter talked her mother into allowing her to try soft contact lenses. They went elsewhere for this care, which leads me to believe that I may have been too adamant about RGP lenses. The daughter recently asked her mother if she could return to my care and be fit again with RGPs because she did not like becoming more myopic since wearing soft lenses. Regardless of age, patients understand the advantages of RGPs when the facts are presented to them. Understanding the advantages leads to more success.
Dr. Yager: The young population adapts extremely well to RGPs as a whole. In our practice it is about 85 percent.
Dr. Bennett: How do you optimize comfort, both during the fitting and during adaptation?
Dr. Quinn: I apply diagnostic lenses after instilling anesthetic. I tell the patient, "We are going to instill a drop that will help you with the initial adjustment to the lens, which will improve our ability to assess the fit and arrive at the most accurate prescription." At the dispensing visit, I apply lenses that have been soaked at minimum overnight, dim the lights and instruct the patient to look down initially until the lenses have enough time to settle (about 10 minutes) so the patient has the opportunity to experience improvement in comfort. I make all lenses lenticular in design if appropriate and prefer a lid attachment approach to minimize lid sensation from blinking over the edge. I request a medium blend and generally use a moderate (30 to 50) Dk fluorosiliconeacrylate (FSA) lens material to maximize wetting.
Dr. Walline: I use anesthetic drops at the fitting and dispensing visits. This allows for a more gradual adaptation, permits me to better assess the vision and fit and makes it easier to insert/remove the lenses for the child. I start with a four-hour wearing time and increase rapidly (two hours per day) until full-time wear is achieved.
Dr. Rinehart: First, I never use topical anesthesia. I explain that they will feel a slight awareness of the lens but it should not "hurt." I let them know that I have been wearing rigid lenses for 36 years, and I distinctly remember that first day. I tell them that the sensation that they will feel is not so much on the eye as on the lids. It is less scary to have something irritate the lid. To demonstrate this, once I place the lens on the eye, but prior to releasing the lids, I ask if they feel the lens. The usual response is no. I remind them that as I release the lid they will feel the lens, and the most comfortable position for them will be to look down towards their feet. I want them to feel they are in control of their contact lens wear and understand that if they adapt slower than expected, they are not failing. It is important they feel emotionally comfortable with this new means of correction.
A well-fitting, large diameter gas permeable
Dr. Bennett: Are you able to fit young athletes into RGPs?
Dr. Rinehart: A significant number of the youngsters I fit are athletes. In fact, show me a 12-year-old who doesn't run, jump, roll around and perform all sorts of athletic moves. I tend to fit slightly larger than average lenses, so I don't really make a conscious design change for the young athlete. The one exception is I may fit the very low (-1.00D) myopic athlete in a reverse geometry lens so that he or she can compete without wearing any lenses.
Dr. Yager: I have many young athletes who wear RGP lenses. I normally use standard designs. When the lens decenters or pops out, I use larger lens designs up to a 12.0mm to 12.5mm diameter.
Dr. Walline: I tell them to wear their lenses for all activities, including swimming. I tell them to be careful when wiping water out of their eyes and to wear goggles under water or don't open their eyes. I don't design lenses any differently for athletes.
Dr. Quinn: I do fit athletes with RGPs, but I'm reluctant to fit football players due to the potential for lens loss by dislocation. I fit soccer and basketball players with diameters that are perhaps slightly larger than I would normally use in an attempt to minimize the potential for loss of dislocation.
Dr. Bennett: If the Singapore/CLAMP studies show that RGPs do significantly slow the progression of myopia in young people, how will you present this information to current and potential patients?
Dr. Quinn: A pamphlet outlining the positive results of these studies will play an important role during the presentation of gas permeable lenses as the preferred contact lens modality. I will also devote a column of our office newsletter to informing our patients about the results of the studies. I may also add a question to our lifestyle questionnaire that all patients complete prior to their comprehensive exam-
ination about patient interest in reducing myopic progression.
Dr. Yager: I will communicate this information primarily through newsletters and in-office promotional materials. I will consider radio as another possible outlet for this information.
Dr. Rinehart: I already tell my patients that the results of one of the Singapore studies (the previously performed Menicon study as compared to the current study sponsored by Polymer Technology Corporation) show that RGP lens wear slows myopic progression and there are indications that there may be some permanence to the changes. I explain that most of us have known this for years, but we now have a good scientific study to prove it. I go on to explain the basic format of the study and the results. Depending upon the interest level of the patient and parents, this may take moments to several minutes.
Dr. Walline: I will tell more people about the benefits of RGPs for slowing myopia progression, even if they do not ask.
Dr. Yager is in private practice in Orlando, FL, specializing in contact lenses. He has lectured worldwide on contact lenses and acted as a consultant and/or clinical investigator for several contact lens companies.
Dr. Quinn practices in Athens, OH, and has served as a faculty member at The Ohio State University College of Optometry.
Dr. Rinehart practices in Peoria, AZ, emphasizing contact lenses. He is current Chairman of the International Orthokeratology Section of NERF and is a member of the RGPLI Advisory Board.
Dr. Walline is a Senior Research Associate at The Ohio State University College of Optometry and the Principal Investigator of the Contact Lenses and Myopia Progression (CLAMP) Study.
Dr. Bennett is an associate professor of optometry at the University of Missouri-St. Louis College of Optometry and executive director of the RGP Lens Institute.
Contact Lens Spectrum, Issue: October 2000