Patent ID: 7402156

Claim:
A counter pressure device for minimizing drug reflux during ophthalmic drug delivery with a cannula, comprising: a handle; a head coupled to a distal end of said handle, said head comprising a curved, concave surface for contacting a conjunctiva and a notch centrally disposed on said curved, concave surface for removably receiving a cannula, wherein: said head is made of silicone; said curved, concave surface has a radius of curvature of about 10 mm to about 14 mm and a thickness of about 1.2 mm to about 3 mm; said notch has a radius of curvature of about 0.2 mm to about 1 mm; and a portion of said curved, concave surface outside of said notch is formed with a slippage preventing texture comprising a plurality of knurls, each of said knurls having a pyramidal geometry.