Glaucoma surgical options

At Issue posed the following question to a panel of experts: Would you consider newer, less invasive glaucoma surgical options as first-line therapy in patients with mild to moderate visual field loss and high IOP, and why?

Issue: April 2011

No real difference between invasive, noninvasive surgery

Alain Bron, MD:

Alain Bron

According to the European Glaucoma Society guidelines, the goal of glaucoma treatment is to preserve the vision and quality of life of the patient at a sustainable cost for society.

If we refer to quality of life, the Collaborative Initial Glaucoma Treatment Study found that an initial surgery led to a fivefold rate of cataract extraction when compared with medical treatment. If we refer to the cost, we have to keep in mind that the amount given by health care payers is not so high. For instance, in France, it was €901 for a glaucoma surgery or a combined surgery performed in outpatient surgery. So it is impossible to incorporate in this amount the price of a new device such as a drain or any other option.

To me, a surgical glaucoma treatment is invasive as soon as the conjunctiva is dissected because we induce a scar. If a trabeculectomy is needed in the future, we have to remember this statement from Broadway: “In the conjunctiva lies the secret of the success of trabeculectomy.”

Therefore, I do not see any difference between penetrating or nonpenetrating surgeries whatever the type (deep sclerectomy, viscocanalostomy, viscocanaloplasty, etc.). Some other surgical options have been proposed such as pneumotrabeculoplasty, iStent (Glaukos), Gold Micro-Shunt (Solx), etc. These new techniques are still under evaluation.

My first-line therapy in patients with mild to moderate visual field loss and high IOP with an open angle still remains a prostaglandin analogue and then a combination of medication if needed. The management could be different with an angle-closure presentation.

References:

Broadway DC, Grierson I, O’Brien C, Hitchings RA. Adverse effects of topical antiglaucoma medication. II. The outcome of filtration surgery. Arch Ophthalmol. 1994;112(11):1446-1454.

European Glaucoma Society guidelines. Third edition, 2008. Dogma, Italy.

Lichter PR, Musch DC, Gillespie BW, et al; CIGTS Study Group. Interim clinical outcomes in the Collaborative Initial Glaucoma Treatment Study comparing initial treatment randomized to medications or surgery. Ophthalmology. 2001;108(11):1943-1953.

Muselier A, Mathieu B, Aube H, Creuzot-Garcher C, Bron A. Impact of the Activity-Based Financing (11th Version) on glaucoma surgery payment in hospital resources. J Fr Ophtalmol. 2009;32(10):701-706.

Alain Bron, MD, can be reached at Hopital Général, 3 Rue de Faubourg Raines, BP 519 21033 Dijon, France; +33-3-80293756/80293277; fax: +33-3-80293589; email: alain.bron@chu-dijon.fr.

Disclosure: Dr. Bron has no direct financial interest in the products discussed in this article, nor is he a paid consultant for any companies mentioned.

Minimally invasive glaucoma surgery an excellent first-line treatment option

Elie Dahan, MD:

Elie Dahan

Minimally invasive glaucoma surgery (MIGS) as first-line therapy is not only safer, but it also has an invaluable advantage in terms of achieving “complete success” (IOP control without medical therapy) because it is performed on a virgin conjunctiva. The adverse effects of prior medical therapy on the outcomes of surgery are well known, and they have been well documented clinically and histologically. Complete success is 4.7 times higher in virgin eyes compared with eyes that were treated for years with topical medication.

Glaucoma control by surgery only is the desire of every glaucoma surgeon, especially if surgery is safer and efficient. This is particularly true for patients with long life expectancy or for cases in which medical therapy is expected to fail. Therefore, it is logical to offer MIGS as first-line therapy even in patients with moderate visual field loss because of its safety and the expected improved surgical outcomes.

Several types of MIGS are currently available:

1. Deep sclerectomy and viscocanalostomy, being nonpenetrating glaucoma surgery, need a long learning curve in order to yield good results.

2. The minimally penetrating Ex-PRESS (Alcon) device has a shorter learning curve and has proved its safety and efficacy with more than 60,000 implantations worldwide over the last 10 years.

3. Newer MIGS techniques such as the iStent (Glaukos), the Trabectome (NeoMedix), the Gold Micro-Shunt (Solx) and the CyPass (Transcend Medical), being less bleb-dependent, are promising but still need longer follow-up studies and widespread use before they can be considered valuable.

References:

Bissig A, Rivier D, Zaninetti M, Shaarawy T, Mermoud A, Roy S. Ten years follow-up after deep sclerectomy with collagen implant. J Glaucoma. 2008;17(8):680-686.

Broadway DC, Grierson I, O’Brien C, Hitchings RA. Adverse effects of topical antiglaucoma medication. II. The outcome of filtration surgery. Arch Ophthalmol. 1994;112(11):1446-1454.

Dahan E, Carmichael TR. Implantation of a miniature glaucoma device under a scleral flap. J Glaucoma. 2005;14(2):98-102.

Dahan E, Drusedau MU. Nonpenetrating filtration surgery for glaucoma: control by surgery only. J Cataract Refract Surg. 2000;26(5):695-701.

Maris PJ Jr, Ishida K, Netland PA. Comparison of trabeculectomy with Ex-PRESS miniature glaucoma device implanted under scleral flap. J Glaucoma. 2007;16(1):14-19.

Elie Dahan, MD, can be reached at Ein Tal Eye Center, 17 Brandeis St., Tel Aviv, 62001 Israel; email: elie.dahan@gmail.com.

Disclosure: Dr. Dahan was a member of the scientific advisory board and a paid consultant for Optonol (manufacturer of the Ex-PRESS) until its acquisition by Alcon Laboratories.

Promising option, more research needed

Marco Nardi, MD:

Marco Nardi

My opinion is that new, less invasive glaucoma procedures are promising but need validation in large trials. From a theoretical point of view, gonioscopic procedures have a great potential — they may become an alternative to medical therapy and laser treatment — and have many advantages. In the near future, the algorithm for treatment may be 1) restoring physiological pathway by gonioscopic approach, 2) suprachoroidal pathway by gonioscopic approach, 3) ab externo filtering procedures, and 4) tubes.

Finally, the renewed interest in cyclodestruction with the new device for high-intensity focused ultrasound has to be considered. It may have a role more in initial glaucoma in which there is no need for massive destruction of the ciliary body than in advanced glaucoma where there is the danger of late phthisis.

Marco Nardi, MD, can be reached at Ospedale Santa Chiara, Università di Pisa, Via Roma 67, 56100 Pisa, Italy; +39-050-992599; fax: +39-050-992976; email: marco.nardi@med.unipi.it.
Disclosure: No products or companies are mentioned that would require financial disclosure.

Nonpenetrating surgery offers options for variety of patients

Gordana Sunaric Mégevand, MD, FEBO:

Gordana Sunaric Mégevand

The usual algorithm for glaucoma treatment is medical therapy. In case of no response, this is followed in some cases by laser treatment, and if again there is not sufficient reduction of IOP, surgical treatment is indicated. However, conventional perforating glaucoma surgery may potentially lead to a variety of complications: hypotony, choroidal detachment, hemorrhage, endophthalmitis, cataract, etc. Less invasive glaucoma surgeries such as nonpenetrating surgery have changed our approach to surgical treatment of glaucoma. Because this type of procedure induces far fewer complications than conventional perforating surgery, it may be performed earlier in the course of the disease. Typically in younger phakic patients with mild to moderate optic neuropathy and visual field loss and high IOP not responding to medical treatment who are known to be less responsive to laser treatment, nonpenetrating glaucoma surgery represents a valid option as first-line therapy. Also, patients with allergies or intolerances to medical treatment may benefit from this type of surgery at an earlier time point than one would choose for trabeculectomy.

In addition, the success rate of nonpenetrating surgery is higher in patients who had no previous glaucoma surgery or laser trabeculoplasty.

Because the IOP-lowering effect of these nonpenetrating procedures is usually less than in trabeculectomies, in particular those augmented with mitomycin C or tubes, the former are therefore indicated when the neuropathy is moderate and target pressure not in the low teens. However, these procedures are technically more demanding and time consuming, the learning curve is longer, and surgeons should opt for them only if the proper technique is mastered. Poor pressure lowering success due to incorrect surgical technique has unfortunately made nonpenetrating glaucoma surgery unpopular in the literature.

Gordana Sunaric Mégevand MD, FEBO, can be reached at Clinique Générale, Fondation Rothschild, Geneva, Switzerland; +41223474980; fax: +41223474981; email: gsm@cqi.ch.
Disclosure: No products or companies are mentioned that would require financial disclosure.