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Sodium Hyaluronate
Healon is a sterile, nonpyrogenic, viscoelastic preparation of a highly purified, noninflammatory, high molecular weight fraction of sodium hyaluronate. Healon contains 10 mg/mL of sodium hyaluronate dissolved in physiological sodium chloride phosphate bufferlpH 7.0-7.51. This high molecularweight polymeris made up of repeating disaccharide units of N-acetyl-glucosamine and sodium glucuronate linked by b 1-3 and b 1-4 glycosidic bonds.
Characteristics Sodium hyaluronate is a physiological substance that is widely distributed in the extracellular matrix of connective tissues in both animals and man. For example, it is present in the vitreous and aqueous humor of the eye, the synovialfluid, the skin and the umbilical cord. Sodium hyaluronates prepared from various human and animal tissues are not chemically different from each other. Healon is a specific fraction of sodium hyaluronate developed as an ophthalmo-surgical aid for use in anterior segment and vitreous procedures. It is specific in that: 1. It has a high molecular weight. 2. It is reported to be nonantigenic 16 3. It does not cause inflammatory 2 or foreign body reactions. 4. It has a high viscosity. Furthermore, the 1% solution of Healon is transparent, is reported to
remain in the anteriorchamberforlessthan6days 3 and protects corneal endothelial
cells45 and other ocular structures. Healon does not interfere
with epithelialization and normal wound healing.
Uses Healon is indicated for use as a surgical aid in cataract extraction (intra- and extracapsular), IOL implantation, corneal transplant, glaucoma filtration and retinal attachment surgery. In surgical procedures in the anterior segment of the eye, instillation of Healon serves to maintaina deep anterior chamber during surgery, allowing for efficient manipulation with less trauma to the corneal endothelium and other surrounding tissues. Furthermore, its viscoelasticity helps to push back the vitreous face and prevent formation of a postoperative flat chamber. In posterior segment surgery Healon serves as a surgical aid to gently separate, maneuver and hold tissues. Healon creates a clear field of vision thereby facilitating intra- and postoperative inspection of the retina and photocoagulation.
Applications Cataract Surgery-IOL Implantation A sufficient amount of Healon is slowly, and carefully introduced (using a cannula or needle into the anterior chamber. Injection of Healon can be performed either before or after delivery of the lens. Injection prior to lens delivery will, however, have the additional advantage of protecting the corneal endothelium from possible damage arising from the removal of the cataractous lens.5 Healon may also be used to coat surgical instruments and the IOL prior to insertion. Additional Healon can be injected during surgery to replace any Healon lost during surgical manipulation(see PRECAUTIONS section). Glaucoma Filtration Surgery In conjunction with performing of the trabeculectomy, Healon is injected slowly and carefully through a corneal paracentesis to reconstitute the anterior chamber. Further injection of Healon can be continued allowing it to extrude into the subconjunctival filtration site and through and around the sutured outer scleral flap. Corneal Transplant Surgery After removal of the corneal button, the anterior chamber is filled with Healon. The donor graft can then be placed on top of the bed of Healon and sutured in place. Additional Healon maybe injected to replacethe Healon lost as a result of surgical manipulation (see PRECAUTIONS section). Healon has also been used in the anterior chamber of the donor eye prior to transplantation to protect the corneal endothelial cells of the graft 5 . Retinal Attachment Surgery Healon is slowly introduced into the vitreouscavity. By directing the injection, Healon can be used to separate membranes (e.g. epiretinal membranes) away from the retina for safe excision and release of traction. Healon also serves to maneuver tissues into the desired position, e.g. to gently push back a detached retina or unroll a retinal flap. and aids in holding the retina against the sclera for reattachment. HOW SUPPLIED Healon is a sterile, nonpyrogenic, viscoelastic preparation supplied in disposable glass syringes, delivering 0.85 mL, 0.55 mL or 0.4 mL sodium hyaluronate MO mg/mL dissolved in physiological sodium chloride phosphate buffer( pH 7.0-7.5). Each mL of Healon contains 10 mg of sodium hyaluronate, 8.5 mg sodium chloride, 0.28 mg of disodium hydrogen phosphate dihydrate, 0.04 mg of sodium dihydrogen phosphate hydrate and q.s. water for injection U.S.P. Healon syringes are terminally sterilized and aseptically packaged. A sterile single - use 27 G cannula is enclosed in the 0.4 mL,0.55 mL, and 0.85 mL boxes. Refrigerated Healon should be allowed to attain room temperature (approximately 30 minutes) prior to use. For intraocular use. Store at 2 to 8 ° C (35 to 47 ° F). Protect from freezing. Protect from light. Caution Federal wlaw restricts this device to sale by or on the order of a physician. REFERENCES 1. Richter, W., Ryde, M. Zetterstrom, O.: Nonimmunogenicity of a purified sodium hyaluronate preparation in man. Int Arch Appl Immun 59:45-48(1979). 2. Balazs, E. A.: Ultrapure hyaluronic acid and the use thereof. U.S. Patent 4,141, 973(1979). 3. Balazs, E. A., Miller, D & Stegmann, R.: Viscosurgery and the use of Na-hyaluronate in intraocular lens implantation. Lecture, Cannes, France(1979). 4. Miller, D.& Stegmann, R: Use of Na-hyaluronate in anterior segment eye surgery. Am Intra-Ocular Implant Soc J 6 (980b) p 13-15. 5. Pape, L. G.& Balazs, E. A.: The use of sodium hyaluronate (Healon®) in human anterior segment surgery. Ophthalmol 87 (1980) p 699-705. 6.Richter, W.: Non-immunogenicity of purified hyaluronic
acid preparations tested by passive cutaneous anaphylaxis. Int Arch All
47119741 p 211-217.
Healon is extremely well tolerated after injection into human eyes. A transient rise of intraocular pressure postoperatively has been reported in some cases. In posterior segment surgery intraocular pressure rises have been reported in some patients, especially in aphakic diabetics, after injection of large amounts of Healon. Rarely, postoperative inflammatory reactions liritis, hypopyon as well as incidents of corneal edema and corneal decompensation have been reported. Their relationship to Healon has not been established.
No information provided.
No information provided.
Those normally associated with the surgical procedure being performed. Over filling the anterior or posterior segment of the eye with Healon may cause increased intraocular pressure, glaucoma, or other ocular damage. Postoperative intraocular pressure may also be elevated as a result of pre-existing glaucoma, compromised outflow and by operative procedures and sequelae thereto, including enzymatic zonulysis, absence of an iridectomy, trauma to filtration structures, and by blood and lenticular remnants in the anterior chamber. Since the exact role of these factors is difficult to predict in any individual case, the following precautions are recommended: Dont overfill the eye chambers with Healon (except in glaucoma surgery.(See DOSAGE AND ADMINISTRATION: Applications). In posterior segment procedures in aphakic diabetic patients special care should be exercised to avoid using large amounts of Healon. Remove some of the Healon by irrigation and/or aspiration at the close of surgery (except in glaucoma surgery - See DOSAGE AND ADMINISTRATION: Applications). Carefully monitor the intraocular pressure, especially during the immediate postoperative period. If significant rises are observed, treat with appropriate therapy. Care should be taken to avoid trapping air bubbles behind Healon. Because Healon is a highly purified fraction extracted from avian tissues and is known to contain minute amounts of protein, the physician should be aware of potential risks of the type that can occur with the injection of any biological material. Because of reports of an occasional release of minute rubber particles, presumably formed when the diaphragm is punctured, the physician should be aware of this potential problem. Express a small amount of Healon from the syringe prior to use, and carefully examine the remainder as it is injected. Avoid reuse of cannulas. If reuse becomes necessary, rinse cannula thoroughly with sterile distilled water. Sporadic reports have been received indicating that Healonmay become "cloudy" or form a slight precipitate following instillation into the eye. The clinical significance of these reports, if any, is not known since the majority received to date do not indicate any harmful effects on ocular tissues. The physician should be aware of this phenomenon and, should it be observed, remove the cloudy or precipitated material by irrigation and/or aspiration. In vitro laboratory studies suggest that this phenomenon may be related to interactions with certain concomitantly administered ophthalmic medications. Use only if solution is clear.
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