Both atropine and soft bifocal contact lenses have been shown to slow myopia progression, and both can cause changes in choroidal thickness. But the relationship between these mechanisms is unclear. The central hypothesis to be tested in the BAM Study is that atropine and soft bifocal contact lenses each exert their anti-progression actions through a common pathway that involves the choroid. If this is correct, then adding atropine treatment to soft bifocal contact lens wear will lead to a more effective slowing of myopia progression than prescribing soft bifocal contact lenses alone due to the additive effects in the common pathway.