Are you performing more combined surgery in glaucoma patients?

At Issue posed the following question to a panel of glaucoma experts: When performing cataract surgery in a patient with glaucoma, has your threshold for combined surgery increased or decreased? Why?

Prefers phaco and IOLs

Bradford J. Shingleton

Bradford J. Shingleton, MD: Without question, my threshold for performing combined surgery rather than phacoemulsification alone in the setting of combined cataract and glaucoma has decreased. This change is due to the growing body of evidence that supports the beneficial effects of uncomplicated phacoemulsification with posterior chamber IOL implantation on IOP.

IOP tends to decrease slightly in normal, glaucoma suspect and glaucomatous eyes after phacoemulsification. The average decrease of 1 mm Hg to 2 mm Hg tends to be sustained for up to 5 years postoperatively. Glaucoma medication requirements in glaucomatous eyes tend to be reduced initially with a gradual increase to pre-surgery levels at 5 years. Eyes with pseudoexfoliation behave similarly to eyes with primary open-angle glaucoma. Eyes with higher preoperative IOP levels and eyes with narrow angle inlets tend to have even greater IOP reduction that is also sustained over extended follow-up.

Surgery performed via the temporal approach spares superior conjunctiva for subsequent glaucoma surgery, if required. Filtration surgery in pseudophakic eyes with mobile superior conjunctiva is highly successful. Eyes with poor IOP control and significant cupping may still benefit from combined surgery, but increasingly, phacoemulsification with posterior chamber IOL implantation is my initial surgical treatment of choice in patients with visually significant cataract and glaucoma.

• Bradford J. Shingleton, MD, can be reached at Ophthalmic Consultants of Boston Inc., 50 Staniford St., Suite 600, Boston, MA 02114; 617-367-4800; e-mail: bjshingleton@eyeboston.com.

Many approaches

Douglas J. Rhee

Douglas J. Rhee, MD: I have been impressed with the continued improvements in phacoemulsification techniques that have made cataract surgery safer and more efficient. Additionally, the well-known IOP-lowering effect of lens removal by phacoemulsification has resulted in a decreased number of medications for many patients. However, my indications for combined surgery have not changed. I believe that people with compromised trabecular meshwork are at the same risk for dramatic IOP elevations with deleterious consequences to the optic nerve as before.

For patients with controlled IOP, with minimal to moderate glaucoma, and on fewer than three anti-glaucoma medications, I perform cataract surgery alone. For patients with advanced disease, I perform combined cataract surgery with a glaucoma filtration procedure, but not necessarily a trabeculectomy, in all patients.

For patients with uncontrolled IOP, I consider the glaucoma first and may favor sequential filtration surgery followed by cataract removal based on the stage of glaucoma. If the patient has advanced glaucoma, I will offer this sequential approach. If the patient has moderate to severe glaucoma, I would consider a combined procedure. If the patient has early glaucoma, the IOP is within 3 mm Hg of my desired target pressure, and is on less than three medications, then I will consider cataract surgery alone.

My rough guidelines above are for patients with primary open-angle glaucoma. I am more likely to favor the addition of filtration surgery in patients who have pseudoexfoliatative or pigmentary glaucoma (ie, people whose trabecular meshwork are more compromised).

• Douglas J. Rhee, MD, is an assistant professor of ophthalmology at Harvard Medical School and on the faculty of the Massachusetts Eye and Ear Infirmary. He can be reached at 243 Charles St., Boston, MA 02144; 617-573-3670; fax: 617-573-3707; e-mail: dougrhee@aol.com.

Phaco lowers IOP

Louis B. Cantor

Louis B. Cantor, MD: My threshold for performing cataract surgery alone in glaucoma patients has increased as the evidence that phacoemulsification lowers IOP increases. In addition, my own experience has also suggested that cataract surgery alone may be safely performed in many glaucoma patients, though certainly not all. Therefore, I find myself performing fewer combined procedures than I may have performed in the past.

• Louis B. Cantor, MD, can be reached at 702 Rotary Circle, Indianapolis, IN 46202-5175; 317-274-8485; fax: 317-278-1007; e-mail: lcantor@iupui.edu.

Frequent filtration

George L. Spaeth, MD: I currently approach patients who have both cataract and glaucoma a bit differently than I did in the past. Specifically, when the patients have severe glaucoma damage, I am now more certain to perform filtration surgery in combination with cataract extraction. In the past I sometimes performed the filtering surgery first and the cataract extraction later. I rarely do that now.

George L. Spaeth

The control possible with trabeculectomy with releasable sutures, and the improved success when using mitomycin C as recommended by Peng T. Khaw, PhD, FRCOphth, have made simultaneous cataract extraction (phacoemulsification) and trabeculectomy remarkable safe and effective. Patients who have a Disc Damage Likelihood Scale of 7 or higher (the DDLS ranges from 1, meaning no damage, to 10, signifying far-advanced damage) or field loss that cuts close to fixation are at risk for continuing loss of visual field. If that occurs, such patients will develop even more difficulty performing the activities of daily living. Therefore, in such a patient, I believe it is appropriate to do everything reasonable to prevent any further deterioration of the optic nerve and visual field.

In contrast, when the patients have minimal damage, I am now more likely not to perform a filtration procedure in conjunction with cataract extraction than in the past. When patients have relatively little visual field loss, say 10 decibels or less, and a Disc Damage Likelihood Scale score of 5 or less, even if the control of glaucoma is more difficult postoperatively than considered likely, and the person develops more disc or field damage, the person will probably not have any additional problem with activities of daily living. Visual recovery is faster and sometimes better when performing cataract extraction alone without a trabeculectomy.

The other factor relates to the life expectancy (anticipated remaining years to live) of the patient. The more anticipated remaining years to live, the more likely I am to combine the surgery with a trabeculectomy with mitomycin C (or a tube shunt procedure in patients who have had a failed trabeculectomy already).

• George L. Spaeth, MD, can be reached at Wills Eye Hospital, 840 Walnut St., Philadelphia, PA 19107; 215-928-3197; fax: 215-928-0166; e-mail: gspaeth@willseye.org.

Small-incision phaco

James C. Tsai

James C. Tsai, MD: The benefits of small-incision phacoemulsification have increased my own threshold for recommending combined surgery in patients with glaucoma. In a sizable number of cataract alone surgeries, significant reductions of IOP may be obtained with resultant decrease in the number of glaucoma medications required. In addition, temporal clear corneal incisions allow for the undertaking of subsequent filtering surgery in virgin conjunctival tissues. Nevertheless, I am a strong advocate of combined trabeculectomy and phacoemulsification in specific patients and believe that certain surgical modifications can be made to obtain successful long-term IOP control in the majority of these cases.

These surgical modifications include the employment of topical and/or subconjunctival anesthesia in all cases and the use of intraoperative viscoelastics to minimize the risk for hypotony. To secure a diffuse, non-leaking filtering bleb, I usually undertake a fornix-based conjunctival flap, leaving a 1-mm to 1.5-mm skirt at the limbus so that I can perform a running conjunctival closure at the end of the case. This allows for an enhanced filtering bleb with less risk of postoperative wound leak. In the majority of cases, I administer low-dose mitomycin C (0.2 mg/mL to 0.3 mg/mL for 2 minutes) and employ releasable scleral flap sutures.

In cases where there needs to be early bleb modulation and rescue of a failing bleb, postoperative subconjunctival 5-fluorouracil or MMC injections are useful along with bleb needling. In the case of leaking blebs, surgical intervention may be necessary early on. In cases of healing blebs, laser suturelysis can be helpful after the releasable sutures have been pulled. I believe that the key for long-term surgical success is effective and proactive bleb manipulation and modification in the early post-operative period.

• James C. Tsai, MD, Robert R. Young Professor and Chairman, Department of Ophthalmology and Visual Science, Yale University School of Medicine and Chief of Ophthalmology, Yale-New Haven Hospital, can be reached at the Yale Eye Center, 40 Temple St., Suite 1B, New Haven, CT 06510; 203-785-7233; e-mail: James.tsai@yale.edu.