PEDIG translates research to evidence-based care for patients at Mayo Clinic

Aug. 07, 2014

"Perhaps the greatest way that the Pediatric Eye Disease Investigator Group (PEDIG) has impacted ophthalmology at Mayo Clinic has been through the transition to evidence-based care and its effect on our patients — particularly those with amblyopia," says Jonathan M. Holmes, M.D., with the Department of Ophthalmology at Mayo Clinic's campus in Rochester, Minnesota, and immediate past PEDIG national network chair.

Dr. Holmes continues: "Prior to PEDIG, if we saw a child with combined anisometropic and strabismic amblyopia we would simultaneously start glasses (based on the cycloplegic refraction) and fairly intense patching (at least six hours a day). Now, based on the evidence from a series of amblyopia treatment trials, we start glasses first. PEDIG studies show that at least a quarter of children will have resolution of their amblyopia with such optical treatment alone.

"If the child doesn't completely respond to glasses we start low-intensity treatment, offering the parents a choice between patching the fellow eye for two hours each day or applying atropine drops to the fellow eye on Saturday and Sunday. This low-dose approach is much easier for the child and family than previous intense regimes, and effective in the majority of the children.

"If the amblyopia does not completely respond to these low-intensity approaches, we try more intense patching — such as six to eight hours each day — or we change the glasses lens to plano to increase penalization while using atropine.

"Despite these treatment advances, some children are still left with residual amblyopia: Up to 50 percent have worse than 20/25 vision. We continue to investigate alternative approaches, such as oral levodopa as an adjunct to patching. We're also planning a new amblyopia treatment trial that uses binocular game play on an iPad. This approach has shown early promise in pilot studies. By harnessing children's enthusiasm for computer games in PEDIG multicenter randomized trials, it is possible that in a few years we will have evidence that allows us to offer treatment of amblyopia without patching or drops."

Clinical parameter assessment

"Another way PEDIG has influenced our practice is through development of a more rigorous approach to assessing clinical parameters," says Dr. Holmes. "The Mayo Clinic Department of Ophthalmology has led the development of standardized methods for clinical trials to assess visual acuity, stereoacuity and strabismus control. It is also the first to pilot test these measures on patients. By incorporating these methods into day-to-day practice, we've reduced the variability of routine testing.

"The department also led the development of new instruments to assess health-related quality of life, including questionnaires for childhood intermittent exotropia, nasolacrimal duct obstruction and adult strabismus. The new questionnaires, developed for use in PEDIG studies, have been incorporated into routine practice. We can assess patients' needs and their response to treatment from their own perspective."

Clinical trials

Dr. Holmes continues: "PEDIG also provides an avenue for participation in the leadership of clinical trials. Brian G. Mohney, M.D., with the Department of Ophthalmology at Mayo Clinic's campus in Rochester, Minnesota, is currently the national protocol chair for the intermittent exotropia protocol comparing patching therapy to observation. Rochester research team members Sarah R. Mickow and David A. Leske serve on PEDIG protocol planning committees and steering committees. Tomohiko Yamada, O.D., of Rochester, is an investigator in several PEDIG studies. Mickow, Lindsay D. Klaehn and Laura Lepor, C.O., also at Mayo Clinic in Rochester, are masked examiners for several studies.

"Our research team currently participates in two PEDIG randomized clinical trials. We welcome referrals of children who might be eligible," says Dr. Holmes. Studies include:

  • Hyperopia Treatment Study 1 (HTS1), to compare visual acuity outcomes and development of strabismus after three years in children ages 12 to <72 months with moderate hyperopia — spherical equivalent +3.00 diopters (D) to +6.00D — who are prescribed glasses either immediately or later (only after confirmation of prespecified deterioration criteria).
  • Convergence Insufficiency Treatment Study (CITS), to determine the effectiveness of home-based computer therapy for symptomatic convergence insufficiency compared with traditional home-based, near-target push-ups and placebo treatment.

"We plan to launch two new randomized clinical trials in 2014, one studying the new binocular computer game approach to treating amblyopia and one investigating the use of over-minus spectacles to treat childhood intermittent exotropia," says Dr. Holmes.

For more information

Contact Rebecca A. Nielsen, study coordinator, at 507-284-5833 or


The Pediatric Eye Disease Investigator Group (PEDIG) is a national network of pediatric ophthalmologists and pediatric optometrists that conducts randomized clinical trials and observational studies in childhood eye disease to provide practical answers to questions that ophthalmologists face every day in the management of patients. PEDIG involves more than 200 investigators at more than 100 sites and typically runs four to seven simultaneous studies in the areas of amblyopia, strabismus and other childhood ophthalmic conditions. PEDIG is funded by the National Eye Institute of the National Institutes of Health.