The primary objective is to evaluate the safety and tolerability of subretinal administration of AAV2-hCHM, in an inter-subject group dose escalation in individuals with choroideremia, based on a comprehensive clinical monitoring plan. The secondary objectives are to define the dose of AAV2-hCHM required to achieve stable, or improved, visual function/functional vision and to assess development of immune responses to AAV2 and REP-1.