December 2018

GLAUCOMA

Presentation spotlight
Optimizing glaucoma surgery in exfoliative glaucoma


by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer

Glaucoma specialist shares her best strategies to reduce IOP in individuals with PXF

Pressure reduction in glaucoma patients with pseudoexfoliation syndrome requires special considerations. Speaking at the 2018 World Ophthalmology Congress, Sihem Lazreg, MD, Lazreg Ophthalmology, Algiers, Algeria, shared her expertise on the treatment and management of pseudoexfoliative (PXF) glaucoma.
“PXF is a very serious type of glaucoma. The successful long-term management of PXF remains the biggest challenge,” Dr. Lazreg said in her presentation. “Compared to primary open angle glaucoma (POAG), medical treatment renders lower control. It is associated with a more aggressive evolution that tends toward a rapid progression and a worse prognosis. PXF needs a tailored and more anticipating management strategy, however, there is no consensus in the literature on the treatment and management of this glaucoma,” she said.

PXF

PXF syndrome is an age-related systemic condition, with PXF glaucoma seen in up to 50% of eyes with PXF. It is characterized by an abnormal accumulation and deposition of extracellular matrix, protein-like material throughout the anterior segment of the eye, most noticeably along the pupillary border and on the anterior lens capsule. Its pathogenesis has both genetic and environmental factors.
“PXF syndrome is the most common identifiable cause of secondary open angle glaucoma worldwide. Compared to POAG, it runs a more aggressive clinical course with high IOP at onset, faster rates of progression, poor response to medical therapy, and increased need for surgical intervention. The prevalence of the condition shows huge variations among different populations, mostly seen among older individuals of Scandinavian and Mediterranean origins,” she said.

Treatment option: trabeculoplasty

Treatment for PXF aims to lower IOP in order to hinder any further glaucomatous optic nerve damage. Medical therapy shows IOP fluctuations and often necessitates adjunctive therapy with either medications and/or laser treatment.
Pseudoexfoliative glaucoma (PXFG) patients frequently require surgical intervention to manage their high IOP. The traditional surgical options for managing PXFG are similar to those for POAG and include laser trabeculoplasty, filtering surgery, and tube shunt implantation. With the advent of microinvasive glaucoma surgery (MIGS) procedures, either alone or in combination with cataract surgery, more options may become available to this patient group.
“Usually PXFG responds well to trabeculoplasty, probably due to the increased pigmentation of the angle, which makes the laser treatment more effective,” Dr. Lazreg said. “Trabeculoplasty can be performed using selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT), in which the IOP-lowering effect is frequently short lived.”
SLT and ALT were seen to achieve equivalent levels of efficacy and side effects in a meta-analysis on the outcomes of all randomized controlled trials up until 2013 that compared the two laser techniques in open angle glaucoma patients (482 eyes). No significant difference was noted in IOP-lowering effects between SLT and ALT at all time points from 1 hour after surgery up to 5 years in patients naive to laser.1 Long-term outcomes of SLT and ALT resulted in similar efficacies and a 50% failure rate after 2 years, although the repeatability of SLT is thought to be one of the advantages over ALT.2
Historically, PXF patients have responded well to ALT, however, the IOP-lowering effect can be short lived, and failure can occur at a faster rate than in POAG patients. The 2-year success rate of primary ALT in PXFG was reported as high as 80% compared to 77% in POAG but declined to 36% in PXFG versus 67% in POAG after 8 years of follow-up.3
Laser application methods can influence outcomes. A systematic review that analyzed trials comparing SLT with other glaucoma treatment options showed that in 17 randomized controlled trials that met the inclusion criteria, no difference was observed overall between SLT and ALT laser treatments in glaucoma patients in terms of IOP-lowering effect. Three trials indicated no difference between 360-degree SLT and medical therapy, with one of the trials indicating greater IOP reduction with latanoprost over 90-degree and 180-degree SLT. Three trials indicated no difference between 180-degree SLT and 360-degree SLT. It was inconclusive whether 90-degree treatments were less efficacious than 180-degree SLT. One trial reported greater IOP reduction with excimer laser trabeculoplasty (ELT) over 180-degree SLT in the long term.4

Treatment option: trabeculectomy

The most widely used surgical procedure in PXFG is by far trabeculectomy with antimetabolites. According to Dr. Lazreg, given the higher mean IOP in PXFG compared to other types of glaucoma and the larger diurnal fluctuations, filtering surgery is often the best choice. “Non-penetrating surgeries that are less efficient in IOP reduction are not recommended for these patients,” she said.
Exfoliation syndrome predisposes to many complications such as capsule rupture, zonular dehiscence, and vitreous loss during cataract extraction. PXF is also associated with an increase in cataract formation. Combined cataract and glaucoma surgery was reported to be an effective treatment in PXFG. “Cataract extraction implies a higher degree of technical difficulty and a larger rate of complications in PXF surgeries. It is recommendable not to delay cataract surgery in individuals with PXF,” Dr. Lazreg explained.
Phacoemulsification cataract surgery resulted in a significant IOP reduction (20%) over a 12-month follow-up period in patients with PXF and POAG, including a significant reduction in the amount of medications needed, particularly in the PXF group.5
“Several studies demonstrated an IOP-lowering effect following cataract surgery, particularly in patients with PXF. Cataract surgery provides a better IOP control in the short to medium term and is often useful in order to avoid or at least delay more invasive filtering surgery,” she said.

Treatment option: EX-PRESS device

The EX-PRESS device (Alcon, Fort Worth, Texas) is a good option in PXF, as it avoids iridectomy and sclerotomy, since the implant is placed into the anterior chamber. The advantage of this over standard trabeculectomy is less inflammation due to decreased manipulation. “This may be especially relevant in PXFG, which can be prone to a heightened inflammatory response following surgery,” Dr. Lazreg noted.
A retrospective review of the records of 100 eyes (100 patients) who underwent trabeculectomy or EX-PRESS device implantation found no differences in IOP reduction or postoperative IOP-lowering medications between the two procedures in POAG and PXFG patients.6

Treatment option: angle-based procedures

“The mechanism underlying elevated IOP in PXF appears to be the accumulation of exfoliation material and/or liberated iris pigment impeding outflow, primarily at the level of the trabecular meshwork. Suppressing obstruction at this junction may be theoretically more advantageous for PXFG over POAG,” Dr. Lazreg said.
One option, trabecular aspiration, was initially developed as a way to increase the trabecular outflow facility in PXFG, either alone or in combination with cataract extraction, by clearing away trabecular debris and pigment and reestablishing physiological outflow. The effect tends to regress 2–4 years after surgery, however, most likely because of a reaccumulation of exfoliation material over time.
Another option, Trabectome (NeoMedix, Tustin, California) mediated ab interno trabeculectomy, showed promise in PXF patients in a recent study that analyzed Trabectome versus phaco-Trabectome outcomes by glaucoma severity.7 Also, viscocanalostomy, a technique that aims to facilitate aqueous flow without completely penetrating the eye, is effective in PXF in reducing IOP when it is combined with cataract surgery, according to Dr. Lazreg.
“Inflammation has been implicated in the development of PXF, and therefore, after surgery, the presence of an increased ocular inflammatory response should be taken into consideration. Also, IOP should be monitored closely and IOP prophylaxis considered in the immediate postoperative period. Early postoperative IOP spikes are more common in PXF eyes, particularly in those with PXFG,” she said.

References

1.Wang W, et al. Selective laser trabeculoplasty versus argon laser trabeculoplasty in patients with open-angle glaucoma: a systematic review and meta-analysis. PLoS One. 2013;8:e84270.
2. Polat J, at al. Repeatability of selective laser trabeculoplasty. Br J Ophthalmol. 2016; 100:1437–41.
3. Kornmann HL, Gedde SJ. Surgical management of pseudoexfoliation glaucoma. Int Ophthalmol Clin. 2014;54:71–83.
4. McAlinden C. Selective laser trabeculoplasty (SLT) vs other treatment modalities for glaucoma: systematic review. Eye (Lond). 2014; 28:249–58.
5. Jimenez-Roman J, et al. Effect of phacoemulsification on intraocular pressure in patients with primary open angle glaucoma and pseudoexfoliation glaucoma. Int J Ophthalmol. 2017;10:1374–1378.
6. Moisseiev E, et al. Standard trabeculectomy and Ex-PRESS miniature glaucoma shunt: a comparative study and literature review. J Glaucoma. 2015;24:410–6.
7. Dang Y, et al. Combined analysis of trabectome and phaco-trabectome outcomes by glaucoma severity. Version 2. F1000Res. 2016;5:762.  

Editors’ note: Dr. Lazreg has no financial interests related to her comments.

Contact information

Lazreg
: slazbkt@yahoo.fr

Optimizing glaucoma surgery in exfoliative glaucoma Optimizing glaucoma surgery in exfoliative glaucoma
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