An alternative treatment, drug therapy with a cycloplegic drug (atropine) that dilates the pupils and blurs the image seen by the sound eye, has been known for almost a century. This method has been widely used for the management of occlusion treatment failures and for maintenance therapy. However, it has seen little use as a primary treatment for amblyopia. Clinical experience has found that it has a high acceptability to patients and parents, and hence high compliance. In addition to its acceptability, pharmacologic therapy has the known advantage over occlusion of providing a wider visual field with both eyes, which may have safety and other functional implications. There is also clinical and laboratory evidence suggesting that drug therapy may maintain and improve the ability to see with both eyes (binocularity).