Method of performing subretinal drainage and agent delivery

A method includes inserting a flexible cannula between a sclera and a choroid of an eye. The needle is advanced from a distal end of the flexible cannula, such that the needle pierces the choroid to access a subretinal space of the eye. The needle is used to aspirate fluid from the subretinal space. The fluid may be present from a retinal detachment, a macular hemorrhage, or other condition present before the procedure begins. The method may further include injecting the fluid in the subretinal space via the needle, in which case the fluid may be a balanced salt solution or other bleb fluid. The method may further include injecting a therapeutic agent into the subretinal space after aspirating the bleb fluid. The volume of injected bleb fluid may be greater than the volume of injected therapeutic agent.