Reference	Type	Description
[9] [12]	SODI (soluble ophthalmic drug insert)	They are oval, sterile, thin films that weigh 15 - 16 mg.
[13]	SODI (soluble ophthalmic drug insert)	It is like a small wafer which softens on insertion. It comprises of soluble copolymers which consist of acryl amide, N-vinyl pyrolidone and ethyl acrylate.
[12]	NODS (New ophthalmic delivery system)	The drugs are administered to the eye in the form of film which is loaded with water soluble drug. It is preservative free and it provides accurate and reproducible dosing, water soluble polyvinyl alcohol film incorporates the drug.
[8]	Collagen shields	It is erodible disc which consist of scleral collagen that is cross linked porcine.
[4]	Artificial tear insert	It is used for the treatment of dry eye disorder, also termed lacrisert. It’s a rod shaped pellet that is designed as artificial tear and provides sustained release. It is made up of hydroxy propyl cellulose and doesnot contain preservative.
[8]	Ocusert	Insoluble flat flexible device consisting of 2 layers in which a reservoir is enclosed. Commercially, it is used to deliver pilocarpine for seven days.
[12]	BODI (Bio adhesive ophthalmic drug inserts)	They belong to soluble inserts group which are made up of synthetic and semisynthetic polymers.
[9]	Hydrogel contact lenses	Their water absorbance is upto 80% which depends on their composition, amount of hydroxyl groups and degree of cross linking.
[8]	Minidisc OTC (ocular therapeutic system)	It is a monolytic device which is shaped like a miniature polymeric contact lens. Its diameter is 4 - 5 mm. with a convex and concave face. The concave face be conventional to the eye sclera.
[9]	Minidisc OTC (ocular therapeutic system)	The OTS offer extended release of water soluble and water insoluble drugs because it may be hydrophilic or hydrophobic.
[14]	Non biodegradable implants	It has non biodegradable polymers coating. It is reservoir type and exhibits the most long lasting release profile of drug because it reserves a large drug amount.
[11]	Biodegradable implants	They provide sustained drug release after being placed in the lower conjunctival sac.
[14]	Biodegradable implants	Processing of this can be into nanoparticles, rods, discs or tablets and many varieties of configurations. As an outcome they stabilize the drug release profile, as well as cut down the drug release extent because the drug content is limited.
[8]	Bio erodible ocular inserts	These comprise of bioerodible polymers such as derivatives of cross linked gelatin and polyester which undergo dissolution and chemical bonds hydrolysis.
[8]	Ocufit SR	It is a rod shaped device made up of silicone elastomer and provides sustained drug release.
[15]	Non erodible inserts	They are non biodegradable. They have superior reliability since they are easily detected when expelled. They have better drug release kinetics.
[9]	Non erodible inserts	Non erodible ocular inserts have dispersed drug so the major mechanism of absorption is passive diffusion.
[8]	Erodible inserts	The polymer is fabricated as hydrophobic but is biodegradable. Drug is released as a result of surface erosion of the insert. After intended drug delivery episode, they don’t require exclusion.