Traditionally amblyopia has been treated by patching the better seeing eye until the amblyopic eye sees as well (or within one line of the visual acuity chart) as the non-amblyopic eye. Until recently, 6 hours a day of patching was typically used as the prescribed amount of time while wearing full time corrective lenses. Current research is unfolding a picture that treats amblyopia differently. If a child is less than 7 years old, treatment can be initiated using lenses alone. Roughly one third of patients are expected to be resolved of amblyopia using only lens wear with no patching. Most people reach the maximum improvement in eyesight they’ll get from lenses within about 3 months.

Ben Patched, February 24, 2006

If amblyopia does not resolve using only lenses, then occlusion can be started. Occlusion can be done by patching, using atropine eye drops, or by blurring the vision in the better seeing eye. When using patching, two hours a day of patching is known to be an effective amount for moderate amblyopia and six hours for severe amblyopia. Patching can be even more effective when the person is engaged in hand-eye coordination activities. Weekend use of atropine can be an alternative to patching for moderate and severe amblyopia. If a child is between the ages of 7 and 17, patching and atropine can still be beneficial if eyesight doesn’t improve with lenses alone. When patching is done 2 hours a day, it’s possible for a person to stop improving. If that happens, increasing the amount to 6 hours a day can result in more improvement.

Once someone reaches their maximum improvement in eyesight with occlusion, it is stopped. It is common for the vision to regress after occlusion is stopped. One quarter to almost half of people treated with occlusion can have residual amblyopia afterward. Occlusion treatment deals with amblyopia as a one-eyed problem. Evidence is mounting to show that amblyopia is in fact a binocular (two-eyed) problem. The binocular vision system structure is present, but the signal from the amblyopic eye is weaker and muted (or suppressed). When occlusion therapy is completed, suppression still exists, and they haven’t achieved binocular function so they still don’t have 3 dimensional depth perception (called stereo blindness).

Patching treatment also has a history of poor results because many people stop participating the therapy. It can be frustrating and difficult to try and function using an eye with reduced vision, and many people drop out. Alternative methods of amblyopia treatment are based on treating the subnormal binocular function and suppression. This type of perceptual learning is found to exist into adulthood. Video games that are designed with enhanced signal to the brain from the amblyopic eye have shown promising results. There is a theoretical concern that a person can get double vision if their suppression is removed, although it hasn’t been reported with the present use of this treatment.

 

amblyopia youtubeAn advanced treatment model for amblyopia is one that follows several stages: prescribed lenses, anti-suppression activities, visual skill and visual information processing development. Successful outcomes of treatment go beyond the traditional visual acuity, into the world of 3 dimensional vision potential with more lasting improved visual processing as a whole. Age is not a barrier to treatment using this approach.

Research is currently underway to investigate the use of perceptual learning using video games to treat amblyopia in children.  Children between 13 and 16 years of age who have worn glasses for several months but are still amblyopic may be eligible to participate.  Parents, please discuss the eligibility requirements with your optometrist.   There are over 90 study sites across the US and Canada, so chances are there is a research location that will work for you and your child.

 

Don’t miss Part 1!

Find a developmental optometrist to discuss treatment options if you or your child are amblyopic.

 

References:

  1. Scheiman MM, Hertle RW, Beck RW, Edwards AR, Birch E, Cotter SA, Crouch ER Jr, Cruz OA, Davitt BV, Donahue S, Holmes JM, Lyon DW, Repka MX, Sala NA, Silbert DI, Suh DW, Tamkins SM; The Pediatric Eye Disease Investigator Group. Randomized trial of treatment of amblyopia in children aged of 7 to 17 years. Arch Ophthalmol 2005; 123:437-47. (ATS-3)
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  5. Pediatric Eye Disease Investigator Group. A randomized trial of near vs distance activities while patching for amblyopia in children aged 3 to less than 7 years. Ophthalmology. 2008 Nov;115(11):2071-8.
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  11. Holmes JM, Melia M, Bradfield YS, Cruz OA, Forbes B; Pediatric Eye Disease Investigator Factors associated with recurrence of amblyopia on cessation of patching. Ophthalmology. 2007 Aug;114(8):1427-32.
  12. Polat U, Ma-Naim T, Spierer A. Treatment of children with amblyopia by perceptual learning. Vision Res. 2009 Oct;49(21):2599-603.
  13. Levi, DM. Prentice Award Lecture 2011: Removing the brakes on plasticity in the amblyopic brain. Optom Vis Sci. 2012 June; 89(6): 827-838.
  14. Mansouri B, Thompson B, Hess Measurement of suprathreshold binocular interactions in amblyopia. Vision Res. 2008 Dec;48(28):2775-84
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