Amblyopia Can Be Treated without Occlusion or Atropine

Abstract

Some types of medical research investigate the unknown to open new pathways to human knowledge. Others examine accepted dogma to prove or deny validity. Perhaps the latter avenue is ultimately more useful because it not only alerts physicians to what is true, but also directs us to abandon a disproven therapy, no matter how long it has been practiced or in how many textbooks it appears. Validation or denial of dogma is an ongoing contribution of the amblyopia treatment trials by the Pediatric Eye Disease Investigator Group (PEDIG). In the 2 related studies in this issue, the PEDIG continues to ask how you should treat a newly diagnosed child with amblyopia. The first study addresses only children with anisometropic amblyopia without strabismus. In actuality, it was largely a study of anisohyperopia, because only 5% of their subjects had myopia. Nonetheless, the finding that about a third completely resolved their amblyopia with spectacles only should change the practice patterns of those who too quickly reach for the patch or the atropine bottle. The investigators used visual acuity (VA) improvement alone to monitor progress. It would have been informative to know the effect of spectacles treatment on binocularity, perhaps as measured by stereopsis, but this was not addressed. Another issue raised as they observed their subjects is the variability inherent in measuring children’s VA. This problem was demonstrated by those patients whose VA allegedly stabilized during this first trial when treated only with spectacles, only later to improve while in the control group of the second study. Those of us who deal with children experience this variability everyday. Previous British studies have also demonstrated that spectacle use alone can improve VA in anisometropic amblyopia. This contribution by the PEDIG has added new information about the variability of the time course for improvement and that possible improvement should be judged over a few visits. They also, for the first time, found that resolution rates were higher with lower levels of anisometropia and with better baseline acuity in the amblyopic eye. The second article compares a nonpatched control group, some of whom were from the first study plus others with strabismic amblyopia, with similar patients treated with 2 hours’ patching a day. For yet unproven reasons, the patched patients also underwent 1 hour of near activities while patched. As the authors reported, there was a modest improvement in the occlusion group relative to the controls. At 5 weeks after treatment, the occluded eye showed a mean improvement of only 0.6 lines more than the improvement found in the control group. If we consider the best-measured VA over the entire follow-up period (beyond 17 weeks), that difference increases to only 0.9 lines. At the end of the