• Visual Acuity Mean Score in the Amblyopic Eye [ Time Frame: 18 weeks ] [ Designated as safety issue: No ]

  Visual acuity is measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol at 18 weeks resulting in an Snellen equivalent acuity score that can range from 20/16 to 20/800. This visual acuity score is converted to logMAR (log of min angle of resolution) for statistical analysis.

  20/16=-0.1 logMAR; best 20/20=0.0 logMAR; 20/25=0.1; 20/32=0.2; 20/40=0.3; 20/50=0.4; 20/63=0.5; 20/80=0.6; 20/100=0.7; 20/125=0.8; 20/160=0.9; 20/200=1.0; 20/250=1.1; 20/320=1.2; 20/400=1.3; 20/500=1.4; 20/640=1.5; 20/800=1.6; worst

  
  
• Visual Acuity Distribution in the Amblyopic Eye [ Time Frame: 18 weeks ] [ Designated as safety issue: No ]

  Visual acuity is measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol at 18 weeks resulting in a Snellen acuity score that can range from 20/16 to 20/800. This visual acuity score is converted to logMAR (log of min angle of resolution) for statistical analysis.

  20/16=-0.1 logMAR; best 20/20=0.0 logMAR; 20/25=0.1; 20/32=0.2; 20/40=0.3; 20/50=0.4; 20/63=0.5; 20/80=0.6; 20/100=0.7; 20/125=0.8; 20/160=0.9; 20/200=1.0; 20/250=1.1; 20/320=1.2; 20/400=1.3; 20/500=1.4; 20/640=1.5; 20/800=1.6; worst

  
  
• Mean Change in Visual Acuity in the Amblyopic Eye [ Time Frame: baseline to 18 weeks ] [ Designated as safety issue: No ]

  Acuity is measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol at baseline and at 18wks resulting in a Snellen acuity score that can range from 20/16 to 20/800. The score is converted to logMAR (log of min angle of resolution) for statistical analysis, and a difference between the scores is calculated.

  A positive difference indicates acuity was better at 18wks than at baseline; a negative difference indicates acuity was worse at 18wks than at baseline.

  
  
• Distribution of Change in Visual Acuity in the Amblyopic Eye [ Time Frame: baseline to 18 weeks ] [ Designated as safety issue: No ]

  Acuity is measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol at baseline and at 18wks resulting in a Snellen acuity score that can range from 20/16 to 20/800. The score is converted to logMAR (log of min angle of resolution) for statistical analysis, and a difference between the scores is calculated.

  A positive difference indicates acuity was better at 18wks than at baseline; a negative difference indicates acuity was worse at 18wks than at baseline.

  
  

• Randot Preschool Stereoacuity at 18 Weeks- Participants With All Causes of Amblyopia [ Time Frame: 18 weeks ] [ Designated as safety issue: No ]
  The Randot Preschool Stereotest measures stereopsis from 800 to 40 seconds of arc on patients as young as 2 years of age. This Stereotest is designed as a matching game in which the patient matches pictures in a test booklet wearing special glasses. A subject can fail the pretest (not see any pictures) or can score >800 (the worst), 800, 400, 200, 100, 60, or 40 (the best) seconds of arc. If two shapes are identified correctly the patient progresses to the next lower stereoacuity level. A failed test occurs when the patient cannot identify any shapes.
  
  
• Randot Preschool Stereoacuity at 18 Weeks- Anisometropic Participants Only [ Time Frame: 18 weeks ] [ Designated as safety issue: No ]
  The Randot Preschool Stereotest measures stereopsis from 800 to 40 seconds of arc on patients as young as 2 years of age. This Stereotest is designed as a matching game in which the patient matches pictures in a test booklet wearing special glasses. A subject can fail the pretest (not see any pictures) or can score >800 (the worst), 800, 400, 200, 100, 60, or 40 (the best) seconds of arc. If two shapes are identified correctly the patient progresses to the next lower stereoacuity level. A failed test occurs when the patient cannot identify any shapes.
  
  
• Mean Change in Visual Acuity in the Sound Eye [ Time Frame: baseline to 18 weeks ] [ Designated as safety issue: No ]

  Acuity is measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol at baseline and at 18wks resulting in a Snellen acuity score that can range from 20/16 to 20/800. The score is converted to logMAR (log of min angle of resolution) for statistical analysis, and a difference between the scores is calculated.

  A positive difference indicates acuity was better at 18wks than at baseline; a negative difference indicates acuity was worse at 18wks than at baseline.

  
  
• Distribution of Change in Visual Acuity in the Sound Eye [ Time Frame: baseline to 18 weeks ] [ Designated as safety issue: No ]

  Acuity is measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol at baseline and at 18wks resulting in a Snellen acuity score that can range from 20/16 to 20/800. The score is converted to logMAR (log of min angle of resolution) for statistical analysis, and a difference between the scores is calculated.

  A positive difference indicates acuity was better at 18wks than at baseline; a negative difference indicates acuity was worse at 18wks than at baseline.

  
  
• Visual Acuity Distribution in the Sound Eye [ Time Frame: 18 weeks ] [ Designated as safety issue: No ]

  Acuity is measured in each eye using the Amblyopia Treatment Study (ATS) visual acuity testing protocol at baseline and at 18 wks resulting in a Snellen acuity score that can range from 20/16 to 20/800. This acuity score is converted to logMAR (log of min angle of resolution) for statistical analysis.

  20/16=-0.1 logMAR; best 20/20=0.0 logMAR; 20/25=0.1; 20/32=0.2; 20/40=0.3; 20/50=0.4; 20/63=0.5; 20/80=0.6; 20/100=0.7; 20/125=0.8; 20/160=0.9; 20/200=1.0; 20/250=1.1; 20/320=1.2; 20/400=1.3; 20/500=1.4; 20/640=1.5; 20/800=1.6; worst

  
  

Atropine is an effective treatment of moderate amblyopia. Reduction of the plus sphere for the sound eye is an accepted method of enhancing and possibly accelerating the treatment effect. Demonstrating additional value of the plano lens in terms of speed of improvement will shorten the treatment period, possibly improving child and parental compliance, leading to improved overall outcomes for patients with amblyopia. If the plano lens leads to greater improvement, then there will be less permanent visual impairment in patients with a history of amblyopia. It also is important to determine if the use of a plano lens in conjunction with atropine has a deleterious effect on the sound eye, and if yes, how often this occurs.

Little is known about the pharmacologic treatment of severe amblyopia. This study will provide important prospectively determined outcome data at little additional expense.

In a study conducted by the Pediatric Eye Disease Investigator Group, A Randomized Trial Comparing Daily Atropine Versus Weekend Atropine for Moderate Amblyopia, the use of weekend atropine for moderate amblyopia was as effective as daily treatment. Intermittent atropine use (such as using it only on the weekends) has the theoretical potential benefit of the sound eye having some time each week during which cycloplegia is only partial. It is possible that allowing some loss of the cycloplegic effect over the course of each week may be safer for the sound eye.

The study has been designed as a simple trial that, other than the type of amblyopia therapy being determined through the randomization process, approximates standard clinical practice. The two treatment regimes for the 18 week primary treatment period are: 1) Atropine 1% once each weekend day in the sound eye and 2) Atropine 1% once each weekend day in the sound eye plus a plano lens for the sound eye.