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Phaco with viscocanalostomy improves safety, reduces complications in glaucoma patients
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MOBILE, Ala. — Glaucoma patients undergoing cataract surgery benefit from phacoemulsification with viscocanalostomy, according to a recent study.
Unlike standard combined phacoemulsification/trabeculectomy, where “there is a 3% infection rate from blebs, there are no infections with this new procedure,” said investigator H. Wade Faulkner, MD, a cataract implant specialist in private group practice here. In addition, “compliance is no longer a factor in 89% of these patients,” he said.
According to Dr. Faulkner, viscocanalostomy was conceived about 10 years ago by Robert Stegmann, MD, of Pretoria, South Africa. “Because of the very encouraging results I obtained in a series of 146 eyes with cataracts and glaucoma and requiring cataract surgery, I now routinely offer this procedure to all of my cataract surgery patients who have glaucoma,” Dr. Faulkner said.
Learning curve
---Unroofing Schlemm’s
canal and detaching Descemet’s membrane.
At the
American Society of Cataract and Refractive Surgery annual meeting, Dr.
Faulkner explained the combined procedure. Despite the relatively steep
learning curve, “it is well worth it,” he said. The most challenging
aspect of surgery “is unroofing Schlemm’s canal and subsequently
detaching Descemet’s membrane. Most people, including myself, have trouble
at this stage.”
Dr. Faulkner said that 30% of the first 23 eyes required medication for control of the glaucoma. On the other hand, only 6% of the last 123 eyes required medications.
Before implanting the lens, Dr. Faulkner moves around slightly to the superior temporal quadrant where the viscocanalostomy is performed. He delays implantation of the lens until after the viscocanalostomy because “part of the procedure requires collapsing the anterior chamber, and I do not want endothelial implant contact,” he said. The viscocanalostomy consists of making a limbal-based conjunctival flap and a 4- mm by 5-mm scleral flap, followed by a deeper scleral flap under the original, “dissecting down to within a few microns of the ciliary body.” The second flap dissection leaves intact a membrane comprised of trabecular meshwork and Descemet’s, where it is permeable to aqueous humor.
The result of surgery is that the aqueous humor leaves the anterior chamber through the intact Descemet’s membrane, goes into the intrascleral lake through which it gains access to Schlemm’s canal, and subsequently exits via the aqueous veins.
Medications drastically reduced
--- Viscoelastic
is injected into Schlemm’s canal.
Over a period of 34
months, Dr. Faulkner performed the combined procedure in 146 study eyes in
patients who also had glaucoma requiring medications. Average follow-up time
was 22 months (range 9 to 34 months). “Preoperatively, these patients
averaged 1.4 medications per eye, but postoperatively, only 0.2
medications,” Dr. Faulkner said. Total medications for the group were 196
preop compared to 24 postop.
Of the patients on medications preop, average intraocular pressure (IOP) was 19 mm Hg (range 11 to 35). Postop, however, the average IOP decreased to 15 mm Hg (range 4 to 20).
A cohort of 12 patients had cataract surgery and viscocanalostomy in one eye and cataract surgery only in the other eye. “Some would say that just performing a cataract phacoemulsification alone will control the pressure,” Dr. Faulkner said. “The eyes of these 12 patients suggest that this is not true, because only one of the 12 visco plus phaco eyes required medication with an average IOP of 15, whereas 12 of the 12 eyes with phaco only required medications postop for control of the glaucoma.”
At final follow-up, 11% of the 146 eyes required medication for IOP control. Furthermore, in the 39 eyes of African-Americans, only 13% required medications for control, “which is a much better result than I have ever obtained with a trabeculectomy as a combined procedure with cataract surgery by phacoemulsification in this group of patients,” Dr. Faulkner said.
Postop care
Postoperative care is “much, much easier” with the newer procedure, Dr. Faulkner said. “The patients aren’t complaining. They don’t have to come in as often, and you don’t have as many complications.” Among study patients, there was only one incidence each of a flat chamber and a stripped Descemet’s membrane. Following further surgical intervention, “these two patients did quite well. In fact, both were controlled without medication,” Dr. Faulkner said.
“Patients love not having to spend that money on medications because it is out-of-pocket most of the time,” Dr. Faulkner said. “Patients also feel better about their glaucoma, and they do better because they don’t have variations in pressure from not remembering to use the medicines.”
Dr. Faulkner said his three goals with the newer combined procedure are to improve vision, reduce dependency on medications and stabilize the glaucoma without further visual field loss. Especially among African-Americans, the procedure “has made all the difference in the world,” he said. Moreover, “this is a procedure that should not be reserved for the glaucoma specialist only. A general cataract surgeon should also use this.”
For Your Information:
- H. Wade Faulkner, MD, can be reached at 2880 Dauphin St., Mobile, AL 36606; (334) 473-1900; fax: (334) 470-8802; e-mail: hwfaulkne@aol.com.