Intraocular gas injector

1. A hand-held gaseous injector assembly for delivering therapeutic gas to a patient, comprising:

a syringe body with an outlet;

a plunger slidably disposed in the syringe body and with the syringe body, defining a first chamber within the syringe body;

a second chamber disposed within at least one of the syringe body and the plunger, the second chamber comprising:

an internal volume containing at least a first fluid at a pressure greater than that of surrounding atmospheric air;

an opening at a first end of the second chamber; and

a valve mechanism located adjacent the first end of the second chamber, the valve mechanism configured to seal the opening;

a channel and an aperture between the second chamber and the first chamber;

an activation system operatively coupled to the second chamber, the activation system being configured to cause a release of the first fluid from the second chamber into the first chamber through the channel;

an adjustable volume limiter configured to limit movement of the plunger to a plurality of user-selectable positions corresponding to a plurality of volumes of the first chamber;

a filter having:

a first end connected to the outlet of the syringe body,

a second end with a filter orifice, and

a filter element disposed between the first end of the filter and the second end of the filter; and

a flow restrictor connected to the filter orifice and having a restrictor orifice that is smaller than the filter orifice and configured to restrict a flow of the first fluid from the first chamber through the filter orifice such that the first fluid from the second chamber travels from the second chamber, through the valve mechanism located adjacent the first end of the second chamber, through the first chamber, through the first end of the filter, through the filter, through the second end of the filter with the filter orifice and then through the restrictor orifice of the flow restrictor to an exterior of the hand-held gaseous injector assembly;

wherein the flow restrictor is configured to generate back pressure against the flow of the first fluid from the first chamber to expand the first chamber to a desired volume corresponding to a user-selected position of the adjustable volume limiter.

2. The hand-held gaseous injector assembly of claim 1 , wherein the filter is removably connected to the syringe body.

3. The hand-held gaseous injector assembly of claim 1 , wherein the flow restrictor comprises a lumen having a first end configured to receive the first fluid from the filter orifice and a second end comprising the restrictor orifice, wherein the lumen tapers between the first end of the lumen and the second end of the lumen.

4. The hand-held gaseous injector assembly of claim 1 , wherein the flow restrictor is a cap configured to removably engage an outlet of the filter.

5. A hand-held gaseous injector assembly, comprising:

a syringe body with an outlet;

a plunger slidably disposed in the syringe body and with the syringe body, defining a chamber within the syringe body;

an adjustable volume limiter configured to limit movement of the plunger to a plurality of user-selectable positions corresponding to a plurality of volumes of the chamber;

a filter having a first end connected to the outlet of the syringe body and a second end with a filter orifice; and

a flow restrictor connected to the filter orifice and having a restrictor orifice that is smaller than the filter orifice and configured to restrict a flow of fluid from the chamber through the filter orifice such that the fluid leaving the syringe, travels through the first end of the filter, through the filter, through the second end of the filter with the filter orifice and then through the restrictor orifice of the flow restrictor to an exterior of the hand-held gaseous injector assembly;

wherein the flow restrictor is configured to generate back pressure against the flow of the fluid from the chamber to expand the chamber to a desired volume corresponding to a user-selected position of the adjustable volume limiter.

6. The hand-held gaseous injector assembly of claim 5 , further comprising a filling mechanism configured to direct the fluid into the chamber.

7. The hand-held gaseous injector assembly of claim 5 , wherein the filter is removably connected to the syringe body.

8. The hand-held gaseous injector assembly of claim 5 , wherein the flow restrictor comprises a lumen having a first end configured to receive the fluid from the filter orifice and a second end comprising the restrictor orifice, wherein the lumen tapers from a larger size at the first end of the lumen to a smaller size at the second end of the lumen.

9. The hand-held gaseous injector assembly of claim 5 , further comprising a valve mechanism having a first position and a second position, the valve mechanism configured to prohibit the flow of the fluid from the chamber when in the first position and to permit the flow of the fluid from the chamber when in the second position.

10. The hand-held gaseous injector assembly of claim 5 , wherein the flow restrictor is a cap configured to removably engage an outlet of the filter.

11. A hand-held gaseous injector assembly, comprising:

a syringe body comprising an endwall and an outlet connected to the endwall;

a plunger slidably disposed in the syringe body and with the syringe body, defining a first chamber within the syringe body and between the plunger and the endwall, the plunger being disposed at the endwall of the syringe body such that the first chamber comprises a volume definable by movement of the plunger;

a second chamber, the second chamber comprising an internal volume containing at least a first fluid at a pressure greater than that of surrounding atmospheric air, wherein the second chamber is fluidically coupled to the first chamber for release of the first fluid from the second chamber to the first chamber;

a filter having a first end connected to the outlet of the syringe and a second end with a filter orifice; and

a flow restrictor connected to the filter orifice and configured to restrict a flow of the first fluid from the first chamber through the filter orifice, wherein the flow restrictor comprises a restrictor orifice that is smaller than the filter orifice such that the first fluid leaving the syringe body travels through the first end of the filter, through the filter, through the second end of the filter with the filter orifice and then through the restrictor orifice of the flow restrictor to an exterior of the hand-held gaseous injector assembly;

wherein the flow restrictor is configured to generate back pressure against the flow of the first fluid from the first chamber to expand the first chamber to a desired volume corresponding to a user-selected position of an adjustable volume limiter of the hand-held gaseous injector assembly.

12. The hand-held gaseous injector assembly of claim 11 , wherein the adjustable volume limiter is configured to limit movement of the plunger to a plurality of user-selectable positions corresponding to a plurality of volumes of the first chamber.

13. The hand-held gaseous injector assembly of claim 11 , further comprising a filling mechanism configured to direct the first fluid into the first chamber.

14. The hand-held gaseous injector assembly of claim 13 , wherein the second chamber comprises an opening at a first end of the second chamber and an internal valve mechanism located adjacent the first end of the second chamber, the internal valve mechanism configured to seal the opening.

15. The hand-held gaseous injector assembly of claim 14 , wherein the internal valve mechanism comprises a piston, a seal, and a biasing member, the internal valve mechanism configured to seal the opening at least prior to activation of the hand-held gaseous injector assembly.

16. The hand-held gaseous injector assembly of claim 11 , wherein the filter is removably connected to the syringe body.

17. The hand-held gaseous injector assembly of claim 11 , wherein the flow restrictor comprises a lumen having a first end configured to receive the first fluid from the filter orifice and a second end comprising the restrictor orifice, wherein the lumen tapers between the first end of the lumen and the second end of the lumen.

18. The hand-held gaseous injector assembly of claim 11 , further comprising a valve mechanism configured to move between a first position and a second position, the valve mechanism configured to prohibit the flow of the first fluid from the first chamber when in the first position and to permit the flow of the first fluid from the first chamber when in the second position.

19. The hand-held gaseous injector assembly of claim 18 , wherein the valve mechanism comprises a valve body, a piston, a seal, a valve biasing member, and an internal protruding member.

20. The hand-held gaseous injector assembly of claim 18 , wherein the filter is removably connected to the syringe body, the filter being configured to engage the valve mechanism when coupled to the syringe body so as to transition the valve mechanism from the first position to the second position.