An apparatus has a first fluid conduit, a second fluid conduit, a connector member, an first tubular member, a second tubular member, and an inner cannula. The connector member has first and second passageways in which the first and second fluid conduits are positioned, respectively. A portion of the second tubular member is positioned within the lumen of the first tubular member. A proximal portion of the inner cannula is fixedly secured within the lumen of the first tubular member. The inner cannula lumen is in fluid communication with the first and second fluid conduits via the lumen of the first tubular member and the lumen of the second tubular member. The inner cannula may be inserted into the subretinal space of a human eye to deliver a leading bleb of fluid and then deliver a therapeutic agent, without having to withdraw the inner cannula from the subretinal space between the acts of delivering the leading bleb delivering the therapeutic agent.