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  • PEDIG Studies: Quality Healthcare and Amblyopia Treatment

    By Rebecca S. Braverman, MD
    Amblyopia
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    Clinically effective health care requires informed decisions that lead to evidence-based treatment, and in the case of children with amblyopia, evidence-based treatment has been made possible by Pediatric Eye Disease Investigator Group (PEDIG) research. Well-designed prospective studies lend support to physicians who must recommend treatment that is often challenging and unpleasant to the child and family. Through PEDIG research, amblyopia management with patching, atropine, and spectacle correction have been proven to be clinically effective, patient-centered, and safe. Continued investigation into new amblyopia treatment modalities, as well as discontinuation of ineffective regimens, will further ensure quality health care to children with amblyopia. 

    Patching

    Over- or underutilization of treatment modalities often leads to poor quality health care. Prior to PEDIG trials on the duration of daily patching for amblyopia, full-time patching was commonly recommended. Social stigmata surrounding patching and the associated difficulties of daily life lead to poor compliance and significant family dissatisfaction with treatment. PEDIG studies showed that moderate amblyopia (20/40-20/100) responds equally well to 2 hours/day patching of the sound eye compared with 6 hours/day and full-time patching in young children 3-7 years old.1 Clinicians can now decrease their recommended patching time to 2 hours/day for moderate amblyopia and counsel parents that 62% of patients achieve either 20/30 visual acuity or at least 3 lines of improvement from baseline within about 4 months of treatment. Similarly, 6 hours/day has been shown to be as effective as full-time patching for severe amblyopia (20/100-20/400) with an average of 4.1 lines of vision improvement.2 Initiating treatment before the patient is 5 years old will yield greater improvement and stability of visual acuity compared with treatment initiated in children 7 to 17 years old.3-5 No studies are available to assess the effectiveness of patching 2 hours/day versus 6 hours/day for severe amblyopia. Patching has been found to be safe, as it does not impact the refractive error of the sound eye.6

    Spectacle Correction

    The prescription of full-time glasses in young children is often a bitter pill for parents to swallow. The initial and replacement costs of spectacles, variable cooperation with wear time, and perceived cultural stigmata of wearing glasses are obstacles to treatment success. PEDIG studies have shown that a large percentage (77%) of children with anisometropic amblyopia improve 2 or more lines of vision within 15 weeks of wearing glasses. Children with less anisometropia and better baseline visual acuity tend to show the most improvement with spectacles alone.7 Additional treatment with patching or atropine may be necessary if visual acuity improvement with spectacles alone is incomplete.

    Atropine

    PEDIG has shown that atropine penalization of the sound eye to treat moderate amblyopia is equally effective and enduring as patching.8,9 Weekend-only versus daily atropine penalization showed equal improvement of moderate and severe amblyopia.10,11 Reduced atropine administration frequency will likely lead to improved compliance and parental satisfaction with treatment. Addition of a plano lens to the sound eye treated with atropine has not been shown to be effective.12 Quality of life has been found to be better with atropine penalization compared to patching and can help the physician tailor the best treatment course for the child based on his or her individual needs.13

    Recurrence

    Recurrence of amblyopia is much more likely to occur if treatment is abruptly suspended rather than slowly tapered prior to discontinuation.14 Parents should be counseled that approximately 20% of children will have regression after amblyopia treatment cessation. Surveillance for amblyopia recurrence is necessary.

    Ineffective Treatments

    PEDIG has shown certain treatment modalities do not work. Levodopa has been used for recalcitrant amblyopia for years. However, the most recent study found no improvement of amblyopia through the use of levodopa.15 In an editorial, Creig Hoyt MD, MA, stated “In reference to levodopa as an adjunct therapy for the treatment of amblyopia, it should persuade us that it is time to move on. Twenty-five years of study ha not produced a convincing body of data to justify its clinical use as it has been used in amblyopia treatment.”16

    Future Treatments

    New treatment modalities under investigation follow the theory that amblyopia is a binocular process and treatment should take into account both eyes. Binocular visual stimulation through the use of dichoptic glasses while playing video games is the newest treatment regimen under investigation.17 The Amblyopia Treatment Study 18 (ATS 18) is broken into two arms. A non-inferiority study will compare the effectiveness of 1 hour/day of binocular game play with 2 hours/day of patching in children 5 to 13 years of age. A superiority study will compare the effectiveness of 1 hour/day of binocular game play with 2 hours/day of patching in patients 13 to 17 years of age.

    References

    1. Repka MX, Beck RW, Holmes JM, et al., Pediatric Eye Disease Investigator Group. A randomized trial of patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol. 2003;121(5):603–611.
    2. Holmes JM, Kraker RT, Beck RW, et al., Pediatric Eye Disease Investigator Group. A randomized trial of prescribed patching regimens for treatment of severe amblyopia in children. Ophthalmology. 2003;110(11):2075–2087.
    3. Scheiman MM, Hertle RW, Beck RW, et al., Pediatric Eye Disease Investigator Group. Randomized trial of treatment of amblyopia in children aged 7 to 17 years. Arch Ophthalmol. 2005;123(4):437–447.
    4. Repka MX, Kraker RT, Beck RW, et al., Pediatric Eye Disease Investigator Group. A randomized trial of atropine vs patching for treatment of moderate amblyopia: follow-up at age 10 years. Arch Ophthalmol. 2008;126(8):1039–1044.
    5. Holmes JM, Lazar EL, Melia BM, et al., Pediatric Eye Disease Investigator Group. Effect of age on response to amblyopia treatment in children. Arch Ophthalmol. 2011;129(11):1451–1457.
    6. Repka MX, Melia M, Eibschitz-Tsimhoni M, et al., Pediatric Eye Disease Investigator Group. The effect on refractive error of unilateral atropine as compared with patching for the treatment of amblyopia. J AAPOS. 2007;11(3):300–302.
    7. Cotter SA, Edwards AR, Wallace DK, et al., Pediatric Eye Disease Investigator Group. Treatment of anisometropic amblyopia in children with refractive correction. Ophthalmology. 2006;113(6):895–903.
    8. Pediatric Eye Disease Investigator Group. A randomized trial of atropine vs. patching for treatment of moderate amblyopia in children. Arch Ophthalmol. 2002;120(3):268–278.
    9. Repka MX,Wallace DK, Beck RW, et al., Pediatric Eye Disease Investigator Group. Two-year follow-up of a 6-month randomized trial of atropine vs patching for treatment of moderate amblyopia in children. Arch Ophthalmol. 2005;123(2):149–157.
    10. Repka MX, Kraker RT, Beck RW, et al., Pediatric Eye Disease Investigator Group. Treatment of severe amblyopia with weekend atropine: results from 2 randomized clinical trials. J AAPOS. 2009;13(3):258–263.
    11. Repka MX, Cotter SA, Beck RW, et al. Pediatric Eye Disease Investigator Group. A randomized trial of atropine regimens for treatment of moderate amblyopia in children. Ophthalmology. 2004;111(11):2076–2085.
    12. Pediatric Eye Disease Investigator Group. Pharmacological plus optical penalization treatment for amblyopia: results of a randomized trial. Arch Ophthalmol. 2009;127(1):22–30.
    13. Holmes JM, Beck RW, Kraker RT, et al., Pediatric Eye Disease Investigator Group. Impact of patching and atropine treatment on the child and family in the amblyopia treatment study. Arch Ophthalmol. 2003;121(11):1625–1632.
    14. Holmes JM, Beck RW, Kraker RT, et al., Pediatric Eye Disease Investigator Group. Risk of amblyopia recurrence after cessation of treatment. J AAPOS. 2004;8(5):420–428.
    15. Repka MX, Kraker RT, Dean TW, et al., Pediatric Eye Disease Investigator Group. A randomized trial of levodopa as treatment for residual amblyopia in older children. Ophthalmology. 2015;122(5):874-81.
    16. Hoyt C. What is next in amblyopia treatment? Ophthalmology. 2015 May;122(5):871-3.
    17. Hess RF, Mansouri B, Thompson B. A new binocular approach to the treatment of amblyopia in adults well beyond the critical period of visual development. Restor Neurol Neurosci. 2010;28:793–802.