A minimally invasive jet injector for intravitreal and subconjunctival injection

To evaluate a minimally invasive injector for intravitreal and subconjunctival administration of medications.

The device has a microneedle that communicates with an internal formulation chamber. A piercing depth-limiting flange restricts microneedle penetration to a depth of less than 1 mm and defines the location of the pars plana from the limbus. The jet injector creates a force of up to 1,000 psi, forcing the medication through the remaining sclera/choroid thickness. The device was tested in 28 enucleated rabbit eyes and 9 experimental and 4 control rabbit eyes to define jet pressure for subconjunctival and intravitreal injection.

Injection pressures of 76 to 156 psi were needed for subconjunctival injection and 974 psi for intravitreal injection. Clinical and histologic examinations did not reveal damage to intraocular structures.

The semi-automated jet injector facilitated intravitreal/subconjunctival injection. The microneedle-assisted jet injector minimized the risk of wet injection by anchoring the microneedle in the sclera.