Compound provides effective clear corneal wound sealant

This adhesive may be an added safety measure in clear corneal wounds that may leak because of IOP variation or manual pressure, thereby potentially limiting bacterial inflow through the wound. Anuj Bhargava, MD, FRCSC, reported on the efficacy of this product as an adjunct for wound closure in clear corneal cataract surgery.

"Clear corneal incisions are seemingly replacing scleral tunnel incisions in routine uncomplicated cataract surgeries," explained Dr. Bhargava, a cornea and external diseases fellow at the New York Eye & Ear Infirmary, New York. "However, sutureless corneal incisions may actual-ly increase the risk of endophthalmitis, which has been reported recently in the literature. Wound hydration alone may not guarantee the wound is watertight postoperatively as desired."

"Cyanoacrylate compounds have been used safely for many years in various medical specialties. In ophthalmology, the compound has been used effectively to seal corneal perforations for more than 30 years," Dr. Bhargava said. "[This product] applies easily and smoothly, it is elastic and flexible, and is relatively inexpensive at $9 a bottle retail. This translates to about $0.50 per patient compared with 10-0 nylon, which can cost about $15 a package."

The adhesive is embedded with a substance, known as parabens, that has antimicrobial properties.

Dr. Bhargava recounted previous studies conducted by his group that showed that the sealant "forms a watertight barrier, prevents influx of ocular surface fluid, possesses tensile strength and flexibility, applies easily in a smooth layer, and has a relatively low side-effect profile," he said.

In their most recent study, Dr. Bhargava and colleagues wanted to determine the efficacy and tensile strength of the product as an adjunctive treatment during clear corneal cataract surgery.

The investigators included 25 eyes of 25 patients who underwent clear corneal cataract surgery with IOL implantation. All clear corneal wounds were sealed using the product at the end of the procedure.

IOP was measured by a manometer attached to the eye by a 27-gauge needle.

Dr. Bhargava demonstrated the steps of the surgery. Prior to the application of the sealant, pressing on the posterior wound edge resulted in an egress of fluid, and the IOP was recorded to range from 4 to 25 mm Hg.

The eye then was repressurized and the side port rehydrated. Two to three drops of the sealant were applied to a cellulose sponge and then applied in a couple of layers across the wound, he said.

The adhesive polymerized in about 20 to 30 seconds. The polymerization pro-cess involves the substance's change of color to gray-white. The eye then was reinflated, and pressure was applied to the anterior and posterior lips of the wound. No fluid emanated from the wound.

"During the period of IOP measurement, which increases to 35 to 40 mm Hg, the [octyl-2 cyanoacrylate formulation] is shown to have very good tensile strength," he said.

"The results indicated that all corneal wounds without [the sealant] leaked when pressure varied from 4 to 25 mm Hg. After [the sealant] was applied, no wounds leaked even with applied pressures of up to 40 mm Hg," he added.

"The results indicate that the [product] is an effective, tensile, clear corneal wound sealant of pressures up to 40 mm Hg. [The adhesive] may serve as an effective adjunct when sealing a clear corneal wound that may leak in patients with potential IOP variations. By providing a watertight seal, bacterial influx may be eliminated and the risk of endophthalmitis may be decreased substantially," Dr. Bhargava concluded.