New Treatment Alternative

Can CEaP Work as a Complete Treatment for Neovascular Glaucoma? by Olawale Salami

For decades, ophthalmologists have been working on finding the best treatments for neovascular glaucoma (NVG). A refractory form of glaucoma, NVG is characterized by vessel proliferation involving the iris and the anterior chamber angle, with eventual angle closure and intractable elevation of intraocular pressure (IOP). It is commonly associated with ischemic retinal conditions, such as proliferative diabetic retinopathy (PDR), branch retinal vein occlusion (BRVO), central retinal vein occlusion (CRVO), central retinal artery occlusion (CRAO), and carotid artery occlusion.

Sustained IOP reduction and elimination of neovascular proliferation are critical treatment goals. However, few available treatments can meet both targets simultaneously.

Current treatment options for NVG include pan-retinal photocoagulation (PRP), filtering surgery, anterior retinal cryotherapy (ARC), anti-vascular endothelial growth factor (VEGF) injections, cyclocryotherapy (CCT) and transscleral cyclophotocoagulation (TSCPC). Some procedures such as CCT and TSCPC can produce sustained IOP reduction in NVG by reducing aqueous humor formation. However, their associated complications, such as marked inflammation, hypotony and phthisis, limit their clinical utility in many patient populations.

A patient-friendly treatment alternative for NVG

Endoscopic cyclophotocoagulation (ECP) utilizes a high precision laser beam, which can be delivered to the target tissue under direct visualization at appropriate energy levels. The high accuracy of this technique helps avoid damage and inflammation in surrounding tissue. 1 Therefore, combining endoscopic cyclophotocoagulation and pars plana ablation as one single procedure (ECPplus) could be an effective and safe treatment toward the relief of refractory glaucoma.

So, does this work in patients with NVG? To answer this question, Dr. Chia-Jen Chang and colleagues at the Taichung Veterans General Hospital in Taiwan, developed a combination therapy, known as Combined Endoscope assisted Procedures (CEaP), which involves endoscopic cyclophotocoagulation and pars plana ablation (ECP-plus), combined with endoscopic pan-retinal photocoagulation.

Their findings — summarized in a paper titled Combined Endoscope assisted Procedures (CEaP) as a Complete Treatment for Neovascular Glaucoma — were published recently. 2

In a retrospective and noncomparative interventional case series, the team analyzed data from patients who were diagnosed with NVG, and whose treatment had failed with previous anti-glaucoma drugs, PRP and anti-VEGF treatment. Diagnosis of NVG was confirmed if the patient had vessel growth at the iris and an anterior chamber angle with an IOP > 21 mmHg. Failure following previous treatment was defined as the presentation of neovascularization at the iris and the anterior chamber angle, along with an IOP > 21 mmHg after treatment of more than 3 months. Overall, 25 eyes from 23 patients were included over a 24-month period.

The exclusion criteria included eyes with visual acuity worse than hand movement, along with those patients who had received an intravitreal injection of anti-VEGF within 6 weeks prior to CEaP. Patients who had not received a lens extraction, together with those patients who had received glaucoma filtering surgery, glaucoma implants, ARC, CCT or TSCPC were also excluded.

“In my opinion, the greatest advantage of this technique is its success rate in IOP control.”

Who would benefit more from CEaP?

Dr. Chang provided insights into the group of patients who could derive the greatest benefit from CeaP.

“Generally speaking, patients who have intractable high IOP are candidates to receive ECP,” he shared. “For those who have ischemic retinal diseases such as diabetes mellitus (DM) retinopathy or CRVO, ECP and endoscopic plateletrich plasma (PRP) are one of the treatment options.”

Furthermore, he explained: “The patients who have NVG and who are unsuitable for multiple intravitreal injections of anti-VEGF — for example, patients who have recent cerebrovascular accident history — get the greatest benefit from this combined procedure. Patients of NVG, who have not had an ideal response to previous treatments, can also receive this procedure as the next option,” Dr. Chang added.

Postoperatively, Dr. Chang and colleagues reported that all patients had a lower IOP value than their preoperative value. The mean IOP was 38.2 ± 7.1 mmHg preoperatively, and 10.2 ± 4.7 mmHg (1 day), 13.8 ± 4.6 mmHg (1 week), 15.0 ± 5.3 mmHg (2 weeks), 17.4 ± 4.7 mmHg (1 month), 16.6 ± 4.1 mmHg (3 months), 16.0 ± 5.0 mmHg (6 months), and 15.7 ± 5.5 mmHg (12 months) postoperatively. At the 6th and 12th months, the IOP stabilized rate was 84% and 75%, respectively.

“The 3-month postoperative complications were minimal, and included uveitis and hyphema in 24% and 16% of eyes, respectively, which resolved in the early postoperative period,” Dr. Chang further explained. “Beyond the 6-month postoperative period, two patients experienced hypotony and phthisis bulbi.”

In addition, he said no postoperative cases of retinal detachment, endophthalmitis or any other severe complications were reported.

Practical benefits for patients and surgeons

According to Dr. Chang, there are several important advantages of this technique over existing treatment modalities of NVG.

“Firstly, it is safe, and the complication rate is low, according to literature. It lasts long, and long-lasting means patients do not have to receive multiple treatments,” he said. “The economic burden is low for patients because they do not have to spend a lot on antiVEGF treatments. The ECP-plus and endoscopic PRP procedure takes less than one hour, and the procedure can be done without general anesthesia in most situations. Also, the wound is small, which is 23 to 19 gauge in size. But in my opinion, the greatest advantage of this technique is its success rate in IOP control,” Dr. Chang explained.

According to the results shared by Dr. Chang and his colleagues, CEaP is both safe and effective. However, there are important limitations to its widespread use, including its cost and technical feasibility.

“Another concern is that proficiency in endoscopy requires skills which have a relatively steep learning curve for operators,” Dr. Chang noted. Therefore, he provided practical advice to retinal surgeons who want to learn and integrate this into their practice.

“It is not easy to get a good orientation when a surgeon shifts from microscope view to endoscope view. In order to avoid iatrogenic injuries, surgeons really should practice getting used to the view of the endoscope before applying it to their patients,” he explained.

The retrospective nature, the relatively small sample size, and the lack of a control group were identified as limitations of the study. Therefore, Dr. Chang and colleagues advocated for further research with a larger sample size and longer follow-up periods to buttress the findings from this study.

A complete treatment for NVG

Taken together, the promising results of the study provide convincing evidence that CEaP can result in IOP lowering and NV regression. CEaP is a complete treatment for NVG in controlling IOP and NV growth. The IOP lowering effects can be sustained upon completion of the treatment.

REFERENCES:

1

2 Lin S. Endoscopic cyclophotocoagulation. Br Journal Ophthalmol. 2002;86(12):1434-1438. Cheng YS, Lin SH, Chang CJ. Combined Endoscope assisted Procedures (CEaP) as a complete treatment for neovascular glaucoma. PLoS One. 2020;15(6):e0234798. doi: 10.1371/journal.pone.0234798. eCollection 2020.

Contributing Doctor

Dr. Chia-Jen Chang, MD, PhD., is a vitreoretinal surgeon who specializes in applying endoscope into intraocular surgery, especially vitreoretinal surgery. He is a graduate of National Cheng Kung University in Taiwan and finished his Ph.D. at Chaoyang University of Technology in Taiwan. He has completed his vitreoretinal fellowship at Taichung Veterans General Hospital. He is currently the chief of the Division of General Ophthalmology of the Department of Ophthalmology at Taichung Veterans General Hospital in Taiwan. His clinical interests include endoscopeassisted intraocular surgery, vitreoretinal surgery, diabetic retinopathy, and macular diseases. His research focus is on retinal diagnostic imaging and retinal image analysis.

capmchangcj@gmail.com