What Is an Ophthalmic Viscosurgical Device?

An ophthalmic viscosurgical device (OVD) is a compound used during cataract surgery. Ophthalmic viscosurgical devices are now considered an essential part of cataract surgery. For many years, they were called viscoelastics or viscoelastic agents.

This article will address what OVDs are, how they are used, and any side effects patients may feel if an eye surgeon uses an OVD.

Ophthalmic Viscosurgical Device: What It Is

Ophthalmic viscosurgical devices are clear chemical compounds that resemble gels. They can have a thick consistency and be elastic. These properties make them valuable during eye surgery.

Most OVDs contain:

• Chondroitin sulfate: In the body, this can be found in solid tissue parts such as cartilage.
• Hydroxypropyl methylcellulose: This is something found naturally in cotton and wood but not in humans. It is helpful for wetting and coating the eye.
• Sodium hyaluronate: Hyaluronate is found in most human connective tissues. It has a role in embryonic growth, cell mobility, and wound healing.

The combination of these ingredients will vary depending on the OVD used. The type of OVD selected will depend on which step of cataract surgery the eye surgeon is performing and surgeon preference.

Ophthalmic viscosurgical devices are used during cataract surgery for several reasons:

• They can help move tissue out of the eye without exiting the eye themselves. This is called viscosity.
• They can change their viscosity according to surgical demands.
• They help parts of the eye involved with cataract surgery to maintain their shape and space when instruments are removed. This is called elasticity.
• They can coat parts of the eye, referred to as coatability.

Uses

Ophthalmic viscosurgical devices are used during several parts of cataract surgery:

• To fill the anterior chamber: The anterior chamber is the front area of the eye behind the cornea(the dome-shaped front part of the eye) and the iris (the colored part of the eye). One step of cataract surgery is filling the anterior chamber with an OVD.
• Capsulorhexis: This is an important stage during cataract surgery during which the eye's lens is removed. The use of OVD during capsulorhexis helps to maintain the shape of the cornea and the depth of the anterior chamber.
• Nucleus removal: The nucleus is the central area of the lens that is removed during cataract surgery. An OVD helps provide safety to other parts of the eye near the lens.
• Irrigation and aspiration: This step of cataract surgery removes soft lens material. An OVD is useful at this step as well.
• Implantation of an intraocular lens: Once the lens with the cataract is removed, it is replaced by an artificial lens called an intraocular lens. An ophthalmic viscosurgical device both protects the corneal endothelium (a layer of cells on the posterior corneal surface) during this implantation and keeps the thin membrane around the lens inflated.

Ophthalmic viscosurgical devices also are a regular part of some special cataract surgery techniques, such as the soft shell technique and the ultimate soft shell technique.

Ophthalmic viscosurgical devices also have a role in treating intraoperative floppy iris syndrome, a complication that can occur if a cataract surgery patient is using alpha blockers for an enlarged prostate. A viscoadaptive OVD may assist in expanding the pupil (the opening in the center of the eye) and making the iris stable.

Types of OVDs

There are several types of OVDs:

• Cohesive OVDs: These help to maintain space in surgical steps that do not have a lot of movement. The molecules in cohesive OVDs will stick to one another more easily than some others. Examples of cohesive OVDs include Amvisc, Amvisc Plus, Healon, Healon GV, and Provisc.
• Dispersive OVDs: These separate and help coat a certain area during surgery. Examples of dispersive OVDs include Healon Endocoat, OcuCoat, and Viscoat.
• Viscoadaptive OVDs: Viscoadaptive refers to the different ways this type of OVD will act during cataract surgery according to the flow of fluid controlled by the cataract surgeon. This type of OVD helps to keep the shape of the anterior chamber better than more cohesive OVDs. At a higher flow rate, a viscoadaptive OVD will break up and coat the endothelium. Healon5 is an example of a viscoadaptive OVD.
• Higher viscosity dispersive OVDs: This category of OVDs behaves similarly to a cohesive OVD but also provides protection of the endothelium like that of a dispersive OVD. One type of higher viscosity dispersive OVD is Discovisc.

Benefits

The use of OVDs helped to transform cataract surgery when they were originally introduced. These products make surgery safer by protecting the corneal endothelium and other tissues of the eye.

Improvements in surgical methods can lead to better cataract surgery results for patients.

Ophthalmic viscosurgical devices also make cataract surgery easier in challenging cases. This may include patients with:

• A flat anterior chamber
• Fuchs endothelial dystrophy, a vision problem that affects the cornea
• Hard cataracts
• Intraoperative floppy iris syndrome, a type of small pupil syndrome that can affect cataract surgery
• Pseudoexfoliation syndrome, which causes a build-up of dandruff-like material in the eye and the rest of the body

The type of OVD selected in more challenging cases can make a major difference in the surgical result and patient satisfaction.

Risks

Although OVDs help cataract surgery in many ways, they still have some risks associated with them. These risks include:

• A rise in the intraocular pressure in the eye
• Inflammation of the iris after surgery
• Hypopyon, or inflammatory cells in the eye's anterior chamber (can cause a white spot on the iris)
• Pseudo anterior uveitis, or inflammation affecting the middle of the eye
• Swelling of the cornea

Summary

Ophthalmic viscosurgical devices are chemical compounds used to make cataract surgery safer. Surgeons use them during many steps of cataract surgery.

There are different types of OVDs. A surgeon will select the type of OVD based on personal preference and the surgical step they are completing.

Ophthalmic viscosurgical devices have some associated risks, such as a rise in eye pressure and possible inflammation after surgery.

A Word From Verywell

Cataract surgery is a safe and common surgery used to remove a cloudy lens and replace it with a new artificial lens. Cataract surgeons will take steps to make the surgery as safe as possible. Ask your surgeon if you have any questions about the surgical approach they will use and when they may use OVDs.