A new hydrogel adherent ocular bandage not yet approved by the U.S. Food
and Drug Administration has shown promise for clear-cornea sutureless cataract
surgery wound coverage, reported John A. Hovanesian, MD, at the San Francisco
Continuing Education Symposium.
ReSure Adherent Ocular Bandage (Ocular Therapeutix) is made of a polymer
that is applied as liquid to the clear cornea incision site. The liquid
polymerizes, becomes a gel and covers the wound in situ. In 3 to 5 days, the
material liquefies and either biodegrades or sloughs off in the tears. The
bandage is CE-mark approved and commercially available in select European
markets and Australia, according to the manufacturer.
In the U.S. pilot study testing ReSures safety and efficacy, 20
patients were randomized to receive either ReSure or collagen shield at the
conclusion of their clear-cornea cataract surgery, Dr. Hovanesian, a
Primary Care Optometry News Editorial Board member, reported.
ReSure persisted at the wound site between 24 hours and 3 days after surgery.
Trace remains were seen at 7 days postop.
Incisional healing was excellent with no epithelial defect observed in
study subjects. This material could provide a safe and effective method of
keeping the corneal wounds covered after cataract surgery, Dr. Hovanesian said.
The study enrollment has been completed and the data submitted to the FDA.
Biomaterials for pterygium surgery
Dr. Hovanesian also presented the latest data on tissue adhesives and
new biomaterials used in modern pterygium surgery. While he emphasized the
importance of covering the scleral excision site with tissue to avoid
recurrence, he pointed out that the traditional method of suturing the
conjunctival autograft to the site is time consuming. In addition, the sutures
can be irritating and even painful to the patient.
To simplify the surgery and ease the recovery process, Dr. Hovanesian
recommended tissue adhesive instead of sutures and an amniotic membrane graft
instead of a conjunctival autograft.
|Figure 1. Comparison of postoperative pain after pterygium
excision using sutures vs. tissue adhesive to secure the graft to the scleral
site.Figure 2. The ReSure Adherent Ocular Bandage is present at the
cataract surgery wound site 24 hours postoperatively.
Images: Hovanesian JA
The tissue adhesive, called fibrin glue, utilizes a reaction between
fibrin and thrombin, which are placed on the scleral site and the graft,
respectively. They are permitted to react with each other, adhering the graft
to the sclera. The fibrin and the thrombin are derived from human plasma and
are the components of a blood clot an essential step in the wound
healing process that adheres the sides of the wound to each other.
Fibrin glue is commercially available, Dr. Hovanesian said. It can be
easily purchased and used not only in pterygium surgery, but also in other
anterior surface procedures, such as closing the flap edge after epithelial
ingrowth removal to prevent recurrence, for example. (A pterygium surgery
instructional video is available at
The accompanying chart demonstrates lower postoperative pain index in
patients who underwent pterygium excision with tissue adhesive vs. sutures.
In addition to tissue adhesives, Dr. Hovanesian described the use of
biomaterials that can be used in place of the graft itself. These materials are
derived from human amniotic membrane and are carefully processed to be readily
available for order, storage and easy surgical handling. The amniotic membrane
sheets have the additional benefit of working well with the tissue adhesives,
Calculating IOL power post-LASIK
Victor Chin, MD, director of Cataract and Lens Surgery at Pacific Vision
Institute, presented a case series demonstrating the most advanced techniques
for calculating IOL power in patients with a history of corneal refractive
surgery who are undergoing cataract and refractive lens exchange procedures
Dr. Chin discussed how the change in relative curvature between the
anterior and posterior corneal surface as a result of myopic LASIK will often
be misinterpreted by ophthalmic diagnostic equipment to suggest artificially
high corneal power. He showed that using these measurements to calculate the
proper IOL power may lead to unexpected hyperopic results.
Dr. Chin reviewed how specialized formulas, taking into account the new
corneal shape and the type of refractive correction performed are required for
accurate IOL power calculation. He said the new advanced algorithms that
compensate for these corneal changes are required to prevent refractive
LASIK treatments for hyperopia will also affect keratometry
measurements, he added. However, because the ablation area is more paracentral,
the central cornea may be less affected, and power measurements are more
reliable. Nevertheless, advanced algorithms are still required to produce
reliable refractive outcomes after IOL implantation in these patients, he said.
Dr. Chin also discussed strategies for accurate IOL power calculation
after radial keratotomy. He emphasized that RK affects the anterior and
posterior cornea equally and, consequently, the keratometry readings are less
affected than post-LASIK. Analysis of the central cornea generally yields
accurate corneal power measurements, he said.
Corneal refractive surgery can often introduce optical aberrations, Dr.
Chin added, so aspheric intraocular lens technology should be emphasized as
well, to maximize patients satisfaction.
Dr. Chin emphasized that cataract- and lens-based surgery in patients
with a history of previous corneal refractive surgery are best performed in an
environment with a convenient and seamless transition to LASIK or
photorefractive keratectomy enhancement procedures to ensure that the desired
refractive outcome is ultimately achieved. by Jennifer Le Coq
- Victor Chin, MD, is director of Cataract and Lens Surgery at Pacific
Vision Institute. He can be reached at 1 Daniel Burnham Court, San Francisco,
CA 94109; (415) 922-9500; email@example.com.
- John Hovanesian, MD, is a PCON Editorial Board member.
He can be reached at 24401 Calle De La Louisa, Suite 300, Laguna Hills, CA
92653; (949) 951-2020; firstname.lastname@example.org.
- Disclosures: Dr. Chin has no direct financial interest in any of the
products mentioned in this article nor is he a paid consultant for any
companies mentioned. Dr. Hovanesian is a member of the scientific advisory
board to Ocular Therapeutix and a consultant to IOP Inc., a commercial provider
of human amniotic membrane for eye surgery.