D

1. A method of treating an ophthalmic condition or disease comprising administering to an eye of an individual in need thereof an effective amount of an ophthalmic composition comprising about 0.015 wt % to about 1 wt % pilocarpine or a pharmaceutically acceptable salt of pilocarpine, a buffering agent, and deuterated water, at a pD of from about 4 to about 8, wherein the composition comprises less than 10% w/v of a degradant of pilocarpine after at least two weeks under a storage condition.

2. The method of claim 1 , wherein the ophthalmic composition has a pD of one of: less than about 8, less than about 7.5, less than about 7, less than about 6.5, less than about 6, less than about 5.5, less than about 5, less than about 4.5, or less than about 4 after extended period of time under the storage condition.

3. The method of claim 1 , wherein the ophthalmic composition further has a potency of one of: at least 80%, at least 85%, at least 90%, at least 93%, at least 95%, at least 97%, at least 98%, at least 99% after extended period of time under the storage condition.

4. The method of claim 3 , wherein the extended period of time is one of: about 1 week, about 2 weeks, about 3 weeks, about 1 month, about 2 months, about 3 months, about 4 months, about 5 months, about 6 months, about 8 months, about 10 months, about 12 months, about 18 months, about 24 months, about 36 months, about 4 years, or about 5 years.

5. The method of claim 3 , wherein the storage condition has a storage temperature of from about 16° C. to about 30° C. or from about 20° C. to about 25° C.

6. The method of claim 1 , wherein the pilocarpine is present in the formulation at a concentration of from about 0.001 wt % to about 20 wt %.

7. The method of claim 1 , wherein the ophthalmic composition further comprises an osmolarity adjusting agent, a preservative, a tonicity adjusting agent, a pD adjusting agent, or a combination thereof.

8. The method of claim 7 , wherein the osmolarity adjusting agent is sodium chloride.

9. The method of claim 7 , wherein the preservative is selected from benzalkonium chloride, cetrimonium, sodium perborate, stabilized oxychloro complex, polyquaternium-1, chlorobutanol, edetate disodium, polyhexamethylene biguanide, or combinations thereof.

10. The method of claim 1 , wherein the buffering agent is selected from borates, borate-polyol complexes, phosphate buffering agents, citrate buffering agents, acetate buffering agents, carbonate buffering agents, organic buffering agents, amino acid buffering agents, or combinations thereof.

11. The method of claim 10 , wherein the buffering agent comprises a citrate buffering agent or an acetate buffering agent.

12. The method of claim 1 , wherein the ophthalmic composition has a dose-to-dose ophthalmic agent concentration variation of one of: less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, or less than 5%.

13. The method of claim 1 , wherein the ophthalmic composition has a pD of one of: from about 4 to about 8, from about 4.5 to about 7.5, from about 5 to about 7.0, or from about 6 to about 7.0.

14. The method of claim 1 , wherein ophthalmic composition further comprises a pharmaceutically acceptable carrier.

15. The method of claim 14 wherein the pharmaceutically acceptable carrier further comprises at least one viscosity-enhancing agent.

16. The method of claim 15 , wherein the viscosity-enhancing agent is selected from cellulose-based polymers, polyoxyethylene-polyoxypropylene triblock copolymers, dextran-based polymers, polyvinyl alcohol, dextrin, polyvinylpyrrolidone, polyalkylene glycols, chitosan, collagen, gelatin, hyaluronic acid, or combinations thereof.

17. The method of claim 1 , wherein the ophthalmic composition comprises one of: less than 10% of H2O, less than 8% of H2O, less than 6% of H2O, less than 5% of H2O, less than 4% of H2O, less than 3% of H2O, less than 2% of H2O, less than 1% of H2O, less than 0.5% of H2O, less than 0.1% of H2O, or 0% of H2O.

18. A method of ameliorating or reducing an ophthalmic condition or disease comprising administering to an eye of an individual in need thereof an effective amount of an ophthalmic composition comprising about 0.015 wt % to about 1 wt % pilocarpine or a pharmaceutically acceptable salt of pilocarpine, a buffering agent, and deuterated water, at a pD of from about 4 to about 8, wherein the composition comprises less than 10% w/v of a degradant of pilocarpine after at least two weeks under a storage condition.