Putting Clinical Research into Practice
EVIDENCE-BASED CL PRACTICE
Putting Clinical Research into Practice
Applying clinical research findings can help you advance your pediatric contact lens practice.
BY KATHRYN RICHDALE, OD, PHD, FAAO
Dr. Richdale is an assistant professor and director of the Clinical Vision Research Center at the SUNY College of Optometry. She teaches Advanced Contact Lenses and serves as a clinical attending in the Contact Lens Service at the University Eye Center. She is co-chair of the Contact Lens Assessment in Youth (CLAY) study group and has been an investigator for industry, private and federally funded, research in presbyopia, cornea, and contact lenses. She is a consultant or advisor to B+L and has received educational and research funding from Vistakon, and research funding from Alcon.
The practice of evidence-based medicine requires that practitioners utilize their clinical experience, the current scientific research, and their patients’ informed decision-making process. This article summarizes some of the latest clinical research findings in pediatric contact lenses and suggests ways in which eyecare practitioners can use these findings to provide the best evidence-based care for their young patients.
Levels of Clinical Research Evidence
Many clinical research studies originate from anecdotal findings in routine clinical care (Figure 1). These clinical findings may drive publications of case reports and can bring a general awareness of potential new treatments or an understanding of disease processes.
But case reports alone can be biased by unique circumstances, so when enough evidence mounts in areas of clinical interest, observational and interventional studies need to be conducted to test hypotheses and to provide stronger evidence to support new theories. Several factors in study design, such as the number and diversity of subjects, length of observation, use of objective outcome measures, and type of controls or placebos, should be considered when determining the strength of the evidence. Generally, no single study can provide enough evidence to demonstrate that a new treatment is better than the current standard, and thus clinicians and scientists strive to confirm initial findings with further studies to determine the findings’ robustness across diverse populations or with varied protocols.
Current Research Findings in Pediatric Contact Lenses
First we will look at the latest clinical research results pertaining to infant, children, and teenage contact lens prescribing, then we will discuss how to incorporate these findings into clinical practice.
Contact Lenses for Pediatric Aphakia Treatment options for pediatric aphakia include spectacles, intraocular lenses (IOLs), and soft and GP contact lenses. Aphakic spectacles create severe magnification effects, can easily be removed by infants, and can cause intolerable anisometropia if the cataract is unilateral. Thus, spectacles are not the preferred form of treatment for pediatric aphakia. Until recently, there was little evidence beyond case reports to determine whether contact lenses or IOLs provided better safety and visual outcomes for pediatric aphakes.
The Infant Aphakia Treatment Study (IATS) group set forth to answer this question and randomized 114 infants who had unilateral cataracts to either IOL implant or contact lens fitting following cataract extraction. The IATS contact lens practitioners were allowed to fit either soft or GP contact lenses. Visual acuity outcomes were similar for both the silicone elastomer soft and GP contact lens groups, but with only 12 infants fitted with GP lenses, comparisons within the contact lens group is limited (Russell et al, 2012).
Importantly, the one-year safety and acuity outcomes demonstrated that there were no statistically significant differences in visual acuity between the IOL and contact lens groups; however, there were a significantly greater number and increased severity of adverse events in the IOL group (Table 1) (Plager et al, 2011; Lambert et al, 2010). The IATS group also noted that the cost of IOL implantation following cataract extraction was about 50% higher than the cost of contact lens correction (Carrigan et al, 2013).
Contact Lenses for Children and Teenagers A survey study categorizing more than 105,000 contact lens fits showed that children and teenagers accounted for about 10% to 20% of contact lens fits worldwide (Efron et al, 2011; Walline et al, 2013). From this survey, it’s not clear what proportion of fits were performed for medical reasons (aphakia, anisometropia, etc.) or cosmetic reasons (refractive error that could also be corrected by spectacles). Patients of any age can benefit from cosmetic contact lens wear for optical reasons (i.e., magnification, peripheral vision) and in support of active lifestyles, but there is now evidence to support additional benefits of contact lenses for children and teenagers.
The Adolescent and Child Health Initiative to Encourage Vision Empowerment (ACHIEVE) study enrolled nearly 500 children aged 8 years to 11 years and randomized them to either spectacles or soft contact lenses (Walline et al, 2009). Subjects completed the Pediatric Refractive Error Profile (PREP) survey at enrollment and at study completion (three years), and the study showed that children wearing contact lenses had higher self-perception of their physical appearance, athletic competence, and social acceptance compared to spectacle-wearing kids.
Should practitioners be concerned about increased chair time with minors? The Contact Lenses in Pediatrics (CLIP) study reported that contact lens training took only about 10 to 15 minutes longer for children (8 to 12 years) than for teenagers (13 to 17 years) (Walline et al, 2007).
Contact Lenses for Myopia Control The latest epidemiological reports indicate that more than 40% of Americans are nearsighted, and the frequency of myopia exceeds 80% in parts of Asia (Vitale et al, 2009). Proof of concept that contact lenses can be used to effectively control eye growth and development of refractive state has been provided by studies in non-human primates, which showed that contact lenses that introduce either full-field or peripheral positive defocus (plus power) could slow eye growth and the subsequent development of myopia (Benavente-Perez et al, 2012; Troilo et al, 2009). Both multifocal and orthokeratology lenses are able to correct refractive error on axis, while also adding positive defocus to the retina. These contact lenses are actively being studied as optical treatments for myopia control in humans.
Figure 1. Levels of evidence.
A few groups have explored soft dual-focus and multifocal contact lens designs for myopia control in children. Anstice and Phillips (2011) reported on a trial of 40 children fitted with a single vision contact lens on one eye and a concentric-ring, dual-focus design on the opposite eye. After 10 months, the single vision lens-wearing eye developed more axial myopia, and this finding persisted when the lenses were switched to the opposite eye for an additional 10 months of study (Figure 2). Sankaridurg et al (2011) fitted 45 children with an aspheric multifocal design bilaterally and compared them to a parallel group of spectacle-wearing children. Their one-year results showed a 33% reduction in myopia progression for the group wearing the multifocal contact lens compared to the spectacle group. Walline et al (2013) reported the first two-year results in a population of 27 children fitted with a commercially available multifocal that has alternating spherical and aspheric zones. Compared to a historical control group (single vision soft contact lens-wearing children from the ACHIEVE study), myopia progression was also about one-third less for the children wearing multifocal contact lenses.
Figure 2. Refractive error (A) and axial length (B) findings from within person trial of dual-focus (DF) and single vision distance (SVD) contact lenses. From Anstice and Phillips (2011).
TABLE 1 Surgical complications and post-operative adverse events by group (contact lens [CL] [n=57] and intraocular lens [IOL] [n=57]) in the Infant Aphakia Treatment study*
||CL Group, n (%)
||IOL Group, n (%)
|Other surgical complication
|POST-OPERATIVE ADVERSE EVENTS|
|CL-associated bacterial keratitis
|Corneal opacity due to tight CL
|Corneal edema > 30 days
|* Adapted from Lambert et al (2011)|
Orthokeratology adds positive defocus via the untreated region of the cornea (outside the 4mm to 5mm treatment zone, but within the entrance pupil of the eye). A summary of some of the major studies of orthokeratology for myopia control was published in 2012 (Table 2) (Cho and Cheung, 2012). The early studies used historical controls or non-randomized study designs, but reported similar findings as that of the first randomized controlled study conducted by Pauline Cho’s laboratory in Hong Kong (Cho and Cheung, 2012). Robust results such as these provide greater support for adoption of a new treatment. Together, these studies suggest that current orthokeratology lenses may be an effective method for slowing myopia progression by 30% to 50% compared to single vision contact lenses or glasses.
Contact Lens Safety for Minors As many as four million Americans under the age of 18 wear contact lenses, yet little is known about the material, wear schedule, or indication for wear in minors (Efron et al, 2011; Swanson, 2012). The aforementioned studies have demonstrated that infants, children, and teenagers can safely wear contact lenses within a clinical trial. During a prospective clinical study, contact lenses and lens care products are often provided free of charge, education on proper lens wear and care is comprehensive and continuous, and multiple visits allow monitoring for early warning signs.
But when devices are used among the general population, the rate and types of complications can be considerably different from those observed in clinical trials (Saviola, 2007; Eydelman et al, 2012; Chalmers, 2007). A report in the journal Pediatrics suggested that contact lens wear was the cause of the highest proportion of medical device-associated adverse events for pediatric patients presenting to an emergency room (Wang et al, 2010). Other surveillance reports in select populations also suggested an increase in the rate of contact lens complications, especially in the younger age groups (Yildiz et al, 2012; Jeng et al, 2010).
To better understand potential age-specific risk factors, the U.S. Food and Drug Administration (FDA) called for post-market surveillance of orthokeratology lenses in minors in 2006. The specific aim was to determine the rate of microbial keratitis (MK) in minors as compared to adults, and a retrospective record review was selected as the appropriate study design. The results of this study were published last year and reported on 1,317 wearers from 86 practices across the United States (Bullimore et al, 2013). Of the 2,599 years of orthokeratology wear reviewed, there were only eight cases of corneal infiltrative events, two of which were classified as MK. Although both cases of MK occurred in minors (ages 12 and 16 years), both resolved to 20/20 acuity. The study was not able to demonstrate a difference in the rate of MK for minors versus adults, but the overall rate of MK was reported to be 7.7/10,000 patient years.
Figure 3. Percent of wearers who had a serious and significant contact lens complication in the CLAY study. From Chalmers et al (2011).
There have been no post-market surveillance studies designed to determine the rate of MK with soft contact lens wear in minors, but the Contact Lens Assessment in Youth (CLAY) study group conducted a retrospective review of 3,549 soft contact lens wearers, 1,139 under the age of 18 years (Lam et al, 2011). A total of 522 contact lens interrupting events occurred in 426 wearers. The risk of events increased in the mid-teenage years and peaked in college-age wearers (Wagner et al, 2011). Only four infiltrative events were identified in the 8- to 12-year-old soft contact lens wearers, none of which were classified as MK (Figure 3) (Chalmers et al, 2011). The CLAY studies also demonstrated that daily disposable lens wear was the safest replacement schedule and that any closed eye wear (including napping in contact lenses) increased the risk of complications. If multi-use lenses were worn, hydrogen peroxide cleaning solution also reduced the risk of contact lens complications (Wagner et al, 2011; Chalmers et al, 2011).
Putting Pediatric Contact Lens Research Findings into Practice
The recent literature suggests a significant growth opportunity for contact lens fitting in pediatrics. Practitioners who understand the current scientific evidence and can demonstrate proficiency in pediatric contact lens fitting can set themselves apart from other practices. Such practitioners can increase both patient volume and per patient revenue from examination and fitting fees as well as from lens materials.
Aphakic Infants While we still await the five-year results of the IATS study, it is clear that there are significant benefits of fitting either GP or soft contact lenses post-cataract surgery. Contact lens practitioners could send letters to local surgeons discussing the results of the IATS study and their ability to co-manage pediatric aphakes with contact lenses. Establishing a relationship with a pediatric ophthalmologist could also lead to other referral opportunities.
Pediatric Contact Lens Wear and Myopia Control The prevalence of myopia is on the rise, and refractive error may carry significant risks for debilitating visual disorders; thus, more and younger children may benefit from wearing contact lenses (Flitcroft, 2012). Eyecare practitioners should be aware of not only the optical benefits of contact lenses, but also their significant social and emotional impact on children and teenagers.
TABLE 2 Summary of orthokeratology studies for myopia control*
||CHO ET AL (2005)
||WALLINE ET AL (2009)
||KAKITA ET AL (2011)
||HIRAOKA ET AL (2012)
||SANTODOMINGO-RUBIDO ET AL (2012)
||CHO & CHEUNG (2012)
||7 to 12
||8 to 11
||8 to 16
||8 to 12
||6 to 12
||7 to 10|
|Duration of study (years)
|Myopia control effect
|* Adapted from Cho and Cheung (2012)|
Much work remains to be conducted to determine the best ways to safely and effectively curtail myopia progression. While no device has yet to receive FDA clearance for “myopia control,” there are FDA-approved contact lens options for patients who have progressive myopia. Practitioners desiring to explore these options can educate parents on the current research findings and their vision correction choices beyond single vision glasses. Practitioners can discuss the pros and cons of either orthokeratology or multifocal soft contact lenses (currently labeled for presbyopia) to correct refractive error while also potentially slowing myopia progression.
Maximizing Safe and Healthy Contact Lens Wear Contact lens wearers of any age should be educated on the benefits and risks of contact lens wear. Research has indicated that the incidence of serious contact lens complications is low and that the majority of cases resolve without long-term repercussions; however, complication rates have been shown to increase during the teenage years (Wagner et al, 2011), and thus better education is certainly warranted for teen wearers. It’s also important to inform patients and parents of the best options to mitigate the risk of contact lens complications (i.e., daily disposable lenses or planned replacement daily wear with hydrogen peroxide-based cleaners).
In light of the upcoming meaningful use guidelines (www.cms.gov/Regulations-and-Guidance/Legislation/EHRIncentivePrograms/Meaningful_Use.html), it could benefit both patients and practitioners to document a minor’s understanding of proper lens wear and care. This could be accomplished using a paper or electronic “quiz” and providing verbal and written education for any unsafe behaviors.
The practice of evidence-based medicine means applying current research knowledge to inform the treatment and management of patients. Based on the current epidemiological and clinical research findings, it’s clear that incorporating evidence-based pediatric contact lens fitting and management can provide a variety of benefits for patients. It can also be an excellent way for contact lens practitioners to demonstrate expertise in their field and grow their practice. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #219.
Contact Lens Spectrum, Volume: 31 , Issue: February 2014