How to best treat our cataract patients who have glaucoma remains a topic of discussion among anterior segment surgeons. Combined procedures have been around for many years, but the potential for complications are real and the risk versus benefit has to be carefully considered. This equation may change as new devices become available that promise to simplify the surgical treatment of cataracts concurrent with lowering of intraocular pressure. Vladimir Trubilin, M.D., discusses his approach to this common problem in Russia.
John Vukich, M.D., international editor
In our practice in Russia, as in practices around the world, we have to work with patients who have both glaucoma and cataract, and we must decide whether to do the surgeries together or separately. There are many arguments in favor of combined surgery, including that it can be psychologically and economically advantageous for the patient. There are also arguments against combined surgery, such as the potential for reduced surgical
efficacy, longer surgical time, and higher risk of complications. Recently we introduced in our practice a new original procedure for the combined treatment of glaucoma and cataract. The main aim of this operation is to increase the
hypotension effect of standard phacoemulsification. We call it "vacuum trabeculoplasty ab interno." The
easiest and most convenient way to perform this operation is to use the coaxial I/A handpiece equipped with a bent Intrepid silicone tip (Alcon, Fort Worth, Texas). It is well known that phacoemulsification can give a good hypotension effect. Even in cases when there is no glaucoma at all, IOP is usually reduced by 2-3 mm Hg. In the case of open-angle glaucoma, IOP reduction can exceed 6-8 mm Hg. When we operate on a patient with closed-angle glaucoma, IOP can be lowered even more, up to 13 mm Hg. Statistics of combined glaucoma and phacoemulsification surgeries show that the result of such methods are variable, sometimes not more than 2 mm Hg, in others much better, up to 15 mm Hg.
Combing cataract and glaucoma surgeries requires a delicate balance between surgical elements that often run contrary to one another. Cataract surgery requires a well-dilated pupil, whereas glaucoma surgery oppositely needs a narrow pupil to achieve good filtration in instances of non-penetrating methods or when performing iridectomy in penetrating types. Previously done cataract extraction makes the eye soft; as a result, it can become much more difficult to separate the scleral flaps and make a dosated eyeball opening. Phacosurgery performed just after sinus trabeculectomy can cause exceeding filtration and uncontrolled diffusive bleb formation. Even small transient complications such as hyphema, choroid detachment, and residual cortex can result in a significantly diminished surgical outcome, both with regard to lowering of IOP and overall visual outcome.
After finishing the cortex aspiration and the posterior capsule polishing, we start the procedure by grasping the iris with middle vacuum settings in the area close to the anterior chamber angle. Moving the grasped iris toward the optical axis of the eyeball and a little bit backward, we draw it off, making the anterior chamber deeper, releasing the angle from synechiae, freeing sectors of adhesion, and increasing trabecular permeability. We repeat this technique several times in all accessible areas, up to 300 degrees of circumference.
Simultaneously, aspiration/irrigation helps to remove pigment, pseudoexfoliation, and all other foreign particulates from the trabecular meshwork. It can also mitigate bleeding at the operation site, which can occur in some cases. The procedure can be done just after IOL implantation as well.
Benefits to vacuum
trabeculoplasty ab interno
Vacuum trabeculoplasty ab interno is effective not only in open-angle glaucoma; it also improves aqueous humor outflow after cataract extraction in patients with narrow-angled and even angle-closed cases. The procedure is painless for the patient and typically doesn't require any extra anesthesia or sedation. The post-op period is similar to any other case with cataract extraction. Typically, the result is a stable IOP reduction in most patients with OCT-confirmed angle opening. The procedure does not require special instruments or equipment; it takes minimal time and can be done by all phacosurgeons.
There are a few complications that accompany this type of operation. For example, some bleeding from the iris root vessels can occur. In some glaucoma cases we have neovascularization of the iris with visibly dilated vessels. Mechanical trauma caused by iris traction can rupture these vessels. Another potential complication is pigment dispersion. The pigment layer on the posterior surface of the iris can be partially damaged by mechanical trauma during the procedure. Irrigation and aspiration helps to remove pigment suspension from the aqueous fluid. Contraindications include: neovascular, congenital, previously operated, and other types of complicated glaucoma. In most cases, there is no iris rupture or iris tearing, although these are also potential complications of the procedure. In summary of our approaches to the treatment of patients with a combination of cataract and glaucoma, I will say that it depends upon the stage of the disease. Contraindications include patients who have already undergone some form of cataract and/or glaucoma surgery, patients with neovascular, congenital, or other types of complicated glaucoma.
If we have a compensated or a subcompensated IOP, vacuum trabeculoplasty ab interno is enough to obtain a good post-op result. If IOP is not compensated, we perform non-penetrating, deep sclerectomy with or without canaloplasty followed by standard phacoemulsification 2 days later. In complicated cases we produce penetrated deep sclerectomy with a surgical induction of a uveoscleral outflow and phacoemulsification 1 month later. If we have no compensation of IOP on pseudophakic eyes, we obtain good results implanting the
EX-PRESS Glaucoma Filtration
Editors' note: Dr. Trubilin is chairman, ophthalmology department, Federal Medical Biological Agency, Moscow, and founder, Russian Society of Cataract and Refractive Surgeons. He has no financial interests related to this article.