The next appropriate treatment for patients with uncontrolled glaucoma, who, despite receiving maximum medical treatment and where a guarded filtration procedure (trabeculectomy) or a tube shunt procedure has failed, is often controversial.

Figure 1: Curved and straight laser microendoscopes.

George Spaeth MD associates from the Wills Eye Institute, and I recently reported our study findings on a group of 'ultra-refractory' glaucoma patients treated by endoscopic cyclophotocoagulation (ECP) at the 2009 American Glaucoma Society annual meeting. There are two sets of components in this approach. The first is a 20g laser endoscope that provides combined imaging, illumination, and photocoagulation (Figure 1). The second is the console itself, which provides a xenon light source, high resolution video camera and an 810nm semi-conductor diode laser (Figure 2). Together they are used to simultaneously image and photocoagulate the ciliary processes for 360 degrees, as well as create a confluent row of photocoagulation lesions on the pars plana (Figure 3). The purpose of the treatment was to diminish aqueous production, rather than enhance outflow.

High resistance rate in patients

Figure 2: E2 laser and endoscopy system.

The patients in this study were unique in that their glaucoma was resistant to more 'standard' medical and surgical intervention. In all, 17 eyes were treated. All failed maximum medical therapy and at least one glaucoma surgery. In fact, the mean number of previous glaucoma surgeries was 3.0. Surgery was required in the better eye in 71% of these patients, prior retinal detachment or corneal transplantation was performed in 35% of these ECP treated eyes and the fellow eye was blind in 41% of those treated. An array of glaucoma mechanisms was involved and the mean patient age was 40.5 years.

IOP and visual acuity

Figure 3: Lasered ciliary processes.

The mean preoperative IOP was 25 +/-6.4 mmHg and postoperatively was 10.5 +/-3.8 mmHg (p=>.0005) (Figure 4). Further, 100% of the patients experienced significantly diminished IOP. Mean number of pre-operative medications was 3.8 +/- 1.3 and post-operatively was 0.9 +/- 1.1 (p=>0.0005). Medications were decreased in 82% of the study patients, were unchanged in 18% and did not increase in any patient. Visual acuity improved in 12% of the ECP treated eyes, was unchanged in 82% and decreased in 6%. Few complications were observed. A transient serous choroidal effusion developed in one eye. There was also one patient with a posteriorly dislocated fragment of old cortex that required vitrectomy. Finally, one phakic patient developed significant cataract formation and required surgery. The mean follow-up for these eyes was 17.5 months.

Safety issues

Figure 4: Pre-and post operative intraocular pressure (Mean ± Standard deviation).

The safety of ECP is defined by its effect at the cellular level. This technique has been established by multiple investigators to be specifically ablative to the epithelium of the ciliary processes and spares the underling structures, most importantly, the ciliary body blood vessels. Direct visualization limits the potential for over-treating or under-treating, or the incorporation of non-aqueous producing tissue in the treatment zone. There is no cellular inflammatory reaction, although there may be breakdown of the blood aqueous barrier producing flare or, if more intense, a fibrin reaction.

Remarkable results

The results experienced in this cohort of patients were especially remarkable considering the poor prognosis associated with these refractory eyes. Historical norms indicate that the long-term success of tube implantation to be about 50%. A previously failed tube has a three-fold increase in the risk for failure. Tube implantation has a significant rate of serious complications. Further, the failure of a previous tube increases this risk of complications for subsequent tubes. Transcleral cyclophotocoagulation would be unthinkable in this desperate group of patients due to its high complication and low success rates along with the proclivity for visual loss.

ECP demonstrated a remarkable level of efficacy, while creating few difficulties in this challenging group of patients that otherwise would be faced with poor therapeutic options.