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 buffer (pH 7.0-7.5). This high molecular weight polymer is made up of repeating disaccharide units of N-acetylglucosamine and sodium glucuronate linked by (beta) 1-3 and (beta) 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 synovial fluid, 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:
Furthermore, the 1% solution of Healon® is transparent, is reported to remain in the anterior chamber for less than 6 days 3 and protects corneal endothelial cells 4,5 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 maintain a 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 post-operative 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.
Contraindications: At present there are no known contraindications to the use of Healon® when used as recommended.
Precautions : Those normally associated with the surgical procedure being performed.
Overfilling 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:
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 Healon® may 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 adminstered ophthalmic medications.
Use only if solution is clear.
Adverse Reactions: 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 amount of Healon®.
Rarely, postoperative inflammatory reactions (iritis, hypopyon) as well as incidents of corneal edema and corneal decompensation have been reported. Their relationship to Healon® has not been established.
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).
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.
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® may be injected to replace the 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 trepanation to protect the corneal endothelial cells of the graft 5 .
Healon® is slowly introduced into the vitreous cavity. 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 (10 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 2-8°C.
Protect from freezing.
Protect from light.
Caution: Federal law restricts this device to sale by or on the order of a physician.
References:
Pharmacia & Upjohn Inc.
Uppsala, Sweden
For Pharmacia & Upjohn Inc.
7000 Portage Road
Kalamazoo MI, 49001
Revised: 6/96
Healon is covered by
U.S. patent 4,141,973, 1979
Copyright © 1984, Pharmacia Inc.
All rights reserved