Trial Comparing Daily Atropine Versus Weekend Atropine
Condition: Amblyopia
MeSH terms: Amblyopia
Study type: Interventional
Phase: Phase 4

Summary: 
      The goals of this study are:

        -  To compare the visual acuity outcome in the amblyopic eye after 17 weeks of daily use of
           atropine versus weekend-only use of atropine.

        -  To compare the proportion of patients achieving a complete treatment response (defined
           as amblyopic eye acuity >20/25 or equal to that of the sound eye in the absence of a
           reduction in the sound eye acuity from baseline) with daily atropine versus weekend-only
           atropine.
    

Detailed description: 
      Amblyopia is the most common cause of monocular visual impairment in both children and young
      and middle-aged adults. Patching has been the mainstay of amblyopia therapy. It is generally
      held that the response to treatment is best when it is instituted at an early age and is poor
      when attempted after eight years of age.

      The study 'Occlusion versus Pharmacologic Therapy for Moderate Amblyopia', a randomized trial
      of 419 children meeting entry criteria similar to the current study, found that both atropine
      1% (one drop daily) and patching (6 hours to full time daily) produced visual acuity
      improvement of similar magnitude and that both are appropriate treatment modalities for the
      management of moderate amblyopia in children. Patching has the potential advantage of a more
      rapid improvement in visual acuity and possibly a slightly better acuity outcome, whereas
      atropine has the potential advantage of easier administration and lower cost.

      Through its cycloplegic effect, atropine prevents accommodation, blurring the sound eye at
      near fixation. The blurring effect can be augmented by reducing the spectacle correction of
      hyperopia in the sound eye. The cycloplegic effect lasts at least partially for a week or
      longer. Therefore, some pediatric eye care providers believe that daily use of atropine is
      unnecessary and treatment may be effective at a dosage of as little as once a week. One
      advantage of less frequent dosing is a potential reduction in side effects, including any
      potential adverse effect on the vision in the sound eye (reverse amblyopia), on ocular
      alignment, and on binocularity. The current study will assess whether prescribing atropine
      once a day produces a better visual outcome than does atropine used only on the two weekend
      days.

      In the 'Occlusion versus Pharmacologic Therapy for Moderate Amblyopia' study, the 6-month
      outcome data showed that more patients treated with atropine had a reduction in visual acuity
      of 1 or more lines in the sound eye than did patients treated with patching. Visual acuity
      was decreased from baseline by 1 line in 15% of the atropine group compared with 7% of the
      patching group and by 2 or more lines in 9% of the atropine group and 1% of the patching
      group. Only one patient (in the atropine group) was actively treated for a presumed
      treatment-related decrease in sound eye acuity, with return of acuity to its baseline level.
      Some of the cases of reduced acuity were unequivocally due to the use of improper refractive
      correction for the sound eye testing (including nine cases in which the testing was done with
      a plano lens prescribed for therapeutic effect rather than the proper corrective lens). In
      other cases, we speculated that there was a residual cycloplegic effect of atropine combined
      with improper refractive correction related to previously latent hyperopia becoming manifest
      hyperopia during the period of atropine treatment, although there were not data to fully
      document this in all cases. All 47 atropine group patients with a decrease of one or more
      lines at six months have had subsequent follow-up exams. Acuity on the subsequent testing was
      the same or better than that at baseline in 42 of the 47 patients: 22 while still on atropine
      treatment (11 with the same refractive correction and 11 with a different refractive
      correction) and 20 after atropine was discontinued (6 with the same refractive correction and
      14 with a different refractive correction). In the other five patients, acuity on subsequent
      testing was decreased from baseline by one line (3 on atropine, 2 off atropine). Thus, there
      did not appear to be a long-term safety concern for atropine, but the data were inconclusive
      as to whether atropine caused an actual, though transient, treatment-related decrease in
      sound eye acuity. One of the objectives of the current study will be to provide additional
      data on the effect of atropine on the sound eye.

      The study is a randomized trial comparing atropine regimes for children with moderate
      amblyopia. It will consist of about 160 children. Patients in the daily atropine group
      receive atropine 1% one drop daily in the sound eye. Patients in the weekend atropine group
      will receive atropine 1% twice a week (Saturday and Sunday) in the sound eye. Visual acuity
      is the major study outcome. It is measured after 17 weeks of treatment with either daily or
      weekend atropine.
    

Intervention name(s): Atropine
Intervention type(s): Drug
Intervention MeSH terms: Atropine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment