Biodegradable collagen matrix implant versus mitomycin-C in trabeculectomy: five-year follow-up

Pharmacological Approaches to Modulate the Scarring Process after Glaucoma Surgery

Glaucoma is an acquired optic neuropathy that results in a characteristic optic nerve head appearance and visual field loss. Reducing the IOP is the only factor that can be modified, and the progression of the disease can be managed through medication, laser treatment, or surgery. Filtering procedures are used when target pressure cannot be obtained with less invasive methods. Nevertheless, these procedures require accurate control of the fibrotic process, which can hamper filtration, thus, negatively affecting the surgical success. This review explores the available and potential pharmacological treatments that modulate the scarring process after glaucoma surgery, analyzing the most critical evidence available in the literature. The modulation of scarring is based on non-steroidal anti-inflammatory drugs (NSAIDs), mitomycin, and 5-fluorouracil. In the long term, the failure rate of filtering surgery is mainly due to the limitations of the current strategies caused by the complexity of the fibrotic process and the pharmacological and toxicological aspects of the drugs that are currently in use. Considering these limitations, new potential treatments were investigated. This review suggests that a better approach to tackle the fibrotic process may be to hit multiple targets, thus increasing the inhibitory potential against excessive scarring following surgery.

Device-modified trabeculectomy for glaucoma

BACKGROUND

Glaucoma is an optic neuropathy that leads to visual field defects and vision loss. It is the second leading cause of irreversible blindness in the world. Treatment for glaucoma aims to reduce intraocular pressure (IOP) to slow or prevent further vision loss. IOP can be lowered with medications, laser, or incisional surgery. Trabeculectomy is a surgical approach which lowers IOP by shunting aqueous humor to a subconjunctival bleb. Device-modified trabeculectomy techniques are intended to improve the durability and safety of this bleb-forming surgery. Trabeculectomy-modifying devices include the Ex-PRESS, the XEN Gel Stent, the PreserFlo MicroShunt, as well as antifibrotic materials such as Ologen, amniotic membrane, expanded polytetrafluoroethylene (ePTFE) membrane, Gelfilm and others. However, the comparative effectiveness and safety of these devices are uncertain.

OBJECTIVES

To evaluate the benefits and harms of different devices as adjuncts to trabeculectomy on IOP control in eyes with glaucoma compared to standard trabeculectomy.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was August 2021.

SELECTION CRITERIA

We included randomized controlled trials in participants with glaucoma comparing device-modified trabeculectomy techniques with standard trabeculectomy. We included studies that used antimetabolites in either or both treatment groups.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. change in IOP and 2. mean postoperative IOP at one year. Our secondary outcomes were 3. mean change in IOP from baseline, 4. mean postoperative IOP at any time point, 5. mean best-corrected visual acuity (BCVA), 6. visual field change, 7. quality of life, 8. proportion of participants who are drop-free at one year, 9. mean number of IOP lowering medications at one year, and 10. proportion of participants with complications.

MAIN RESULTS

Eight studies met our inclusion criteria, of which seven were full-length journal articles and one was a conference abstract. The eight studies included 961 participants with glaucoma, and compared two types of devices implanted during trabeculectomy versus standard trabeculectomy. Seven studies (462 eyes, 434 participants) used the Ex-PRESS, and one study (527 eyes, 527 participants) used the PreserFlo MicroShunt. No studies using the XEN Gel Stent implantation met our criteria. The studies were conducted in North America, Europe, and Africa. Planned follow-up periods ranged from six months to five years. The studies were reported poorly, which limited our ability to judge risk of bias for many domains. None of the studies explicitly masked outcome assessment. We rated seven studies at high risk of detection bias. Low-certainty of evidence from five studies showed that using the Ex-PRESS plus trabeculectomy compared with standard trabeculectomy may be associated with a slightly lower IOP at one year (mean difference (MD) -1.76 mmHg, 95% confidence interval (CI) -2.81 to -0.70; 213 eyes). Moderate-certainty of evidence from one study showed that using the PreserFlo MicroShunt may be associated with a slightly higher IOP than standard trabeculectomy at one year (MD 3.20 mmHg, 95% CI 2.29 to 4.11). Participants who received standard trabeculectomy may have a higher risk of hypotony compared with those who received device-modified trabeculectomy, but the evidence is uncertain (RR 0.73, 95% CI 0.46 to 1.17; I² = 38%; P = 0.14). In the subgroup of participants who received the PreserFlo MicroShunt, there was a lower risk of developing hypotony or shallow anterior chamber compared with those receiving standard trabeculectomy (RR 0.44, 95% CI 0.25 to 0.79; 526 eyes). Device-modified trabeculectomy may lead to less subsequent cataract surgery within one year (RR 0.46, 95% CI 0.27 to 0.80; I² = 0%).

AUTHORS' CONCLUSIONS

Use of an Ex-PRESS plus trabeculectomy may produce greater IOP reduction at one-year follow-up than standard trabeculectomy; however, due to potential biases and imprecision in effect estimates, the certainty of evidence is low. PreserFlo MicroShunt may be inferior to standard trabeculectomy in lowering IOP. However, PreserFlo MicroShunt may prevent postoperative hypotony and bleb leakage. Overall, device-modified trabeculectomy appears associated with a lower risk of cataract surgery within five years compared with standard trabeculectomy. Due to various limitations in the design and conduct of the included studies, the applicability of this evidence synthesis to other populations or settings is uncertain. Further research is needed to determine the effectiveness and safety of other devices in subgroup populations, such as people with different types of glaucoma, of various races and ethnicity, and with different lens types (e.g. phakic, pseudophakic).

[Trabeculectomy with mitomycin C and Ologen® implant in comparison to classical trabeculectomy]

BACKGROUND

Trabeculectomy (TE) with mitomycin C (MMC) is considered the gold standard in glaucoma surgery. A new modification is the use of an Ologen® implant (AEON Astron Europe B.V., Leiden, Netherlands) during TE, which was analyzed and compared to the standard TE in this retrospective study.

PATIENTS AND METHODS

On 70 eyes Ologen® was applied during surgery (group 2), whereas 98 eyes were operated on without the implant (group 1). Both surgical procedures were compared regarding the efficiency of lowering the intraocular pressure (IOP), the number of glaucoma medications, the rate of complications and follow-up treatment. Data were collected up to 24 months after surgery.

RESULTS

In group 1 the IOP was lowered from 28.0 mmHg (95% confidence interval, CI 26.6-29.4 mmHg) to 16.0 mmHg (14.0-18.1) after 24 months. In group 2, the pressure dropped from 28.5 mmHg (26.8-30.1) to 14.3 mmHg (11.7-17.0). The IOP reduction was significant in both groups (p < 0.001), there was no significant difference between the groups (p > 0.05). Glaucoma-related follow-up treatments were performed more often in group 1 but the difference was not significant.

CONCLUSION

Both procedures significantly lower the IOP and the number of glaucoma medications. For our cases, TE with Ologen® and MMC is considered to be superior to TE with MMC regarding the lower rates of follow-up treatments as it is less time-consuming for the patients and the clinic.

Combined trabeculotomy-trabeculectomy with and without augmentation in primary congenital glaucoma: triple-armed randomized controlled trial

PURPOSE

To evaluate the efficacy and safety of using Mitomycin-C (MMC) or Ologen implant as an adjunct to combined trabeculotomy-trabeculectomy (CTT) surgery relative to non-augmented CTT surgery in achieving higher success rates in patients with primary congenital glaucoma (PCG).

STUDY DESIGN

A prospective triple-armed randomized controlled clinical trial was conducted in the period between April 2019 and May 2021, targeting 75 eyes of patients with PCG over one year, with patients being followed up for at least one whole year.

PATIENTS AND METHODS

The study included 75 eyes; only 70 fulfilled the inclusion criteria and were randomly assigned to one of the three study groups using a computer program to generate random number list. Eyes were treated by either CTT without augmentation, CTT augmented with MMC, or CTT augmented with Ologen implant. Only 63 eyes completed one year of follow-up and were evenly distributed among the three study groups; with 21 eyes in each group were statistically analyzed.

OUTCOME MEASURES

Our primary outcome measure is to report and compare the percentage of patients who demonstrated complete success with intraocular pressure (IOP) controlled and maintained below 21 mmHg without the use of antiglaucoma medications or additional glaucoma surgery over a one-year follow-up. Secondary outcome measures include reporting failure, intra- and postoperative complications of the three surgical modalities, postoperative corneal diameter, clearance of corneal edema, and postoperative cup/disk (C/D) ratio.

RESULTS

Complete success was achieved in 17 eyes (81.0%) in CTT group, 18 eyes (85.7%) in MMC group, and 17 eyes (81.0%) in Ologen group. Qualified success (IOP < 21 with or without antiglaucoma medications) was achieved in 18 eyes (85.7%) in both the CTT and the Ologen groups, with 19 eyes (90.5%) in the MMC group. Failure was observed in three eyes (14.3%) in both CTT and Ologen groups and two eyes (9.5%) in the MMC group. Based on survival analysis, CTT group had a cumulative success probability of 95.2% at three months, which dropped to 85.7% at six months and remained at that level for the 9th and 12th months of follow-up. With respect to the MMC group, the cumulative success probability at three months was 95.2%, dropped to 90.5% at six months, and remained at that level for the 9th and 12th months of follow-up. While in the Ologen group, the cumulative success probability at three months was 85.7% and remained at the same level during the 6th, 9th, and 12th months of follow-up, with p value = 0.862 using the logrank test.

CONCLUSION

CTT is a safe and effective primary surgical intervention in patients with PCG without the need for augmentation while preserving the augmented procedure's use for recurrent cases.

Trabeculectomy: Does It Have a Future?

The trabeculectomy (TRAB) procedure has undergone various modifications to increase the long-term surgical success and safety profiles. The main issues with TRAB include short and long-term complications, that are more common with the concomitant use of anti-fibrotic agents. While many surgeons have predicted the demise of trabeculectomy amidst newer non-penetrating glaucoma surgeries, it is still the gold standard procedure for patients with an advanced or rapidly progressing disease and for those patients who need very low intraocular pressures. This review article is unique in summarizing the evolution of trabeculectomy and its efficacy compared to neoteric shunt procedures while trying to predict if trabeculectomy has a future in the modern surgical world. We have compared the outcomes and complications of trabeculectomy to all the surgical procedures available to date and have tried to evolve an algorithm to help surgeons to decide on their preferred technique.

The surgical management of glaucoma: A review

After a long period of little change, glaucoma surgery has experienced a dramatic rise in the number of possible procedures in the last two decades. Glaucoma filtering surgeries with mitomycin C and glaucoma drainage devices remain the standard of surgical care. Other newer surgeries, some of which are minimally or microinvasive glaucoma surgeries, target existing trabecular outflow, enhance suprachoroidal outflow, create subconjunctival blebs, or reduce aqueous production. Some require the implantation of a device such as the iStent, Hydrus, Ex-PRESS, XEN and PRESERFLO, whilst others do not-Trabectome, Kahook dual blade, Ab interno canaloplasty, gonioscopy-assisted transluminal trabeculotomy, OMNI and excimer laser trabeculotomy. Others are a less destructive variation of an established procedure, such as micropulse transscleral cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cycloplasty. Cataract surgery alone can be a significant glaucoma operation. These older and newer glaucoma surgeries, their mechanism of action, efficacy and complications are the subject of this review.

Comparison of bleb morphology by anterior segment optical coherence tomography and clinical outcome after phacotrabeculectomy with mitomycin C or Ologen implant

Purpose:

To compare the bleb morphology by Anterior Segment Optical Coherence Tomography (ASOCT) and clinical outcome after Phacotrabeculectomy with either mitomycin C or Ologen implant.

Methods:

In a prospective interventional active controlled study, 93 patients aged 18 years and above underwent phacotrabeculectomy with either mitomycin C (53 eyes) or ologen implant (40 eyes), followed up for 12 months. The primary outcome measure was to note the evolution of bleb morphology by ASOCT in the two groups over 12 months. Secondary outcome measures were mean IOP, reduction in the need for anti-glaucoma medications, and complications seen in the two groups.

Results:

All parameters in the two groups were comparable preoperatively (P>0.05). Best corrected visual acuity at 12 months was 0.38±0.27 in mitomycin group and 0.31±0.23 in ologen group (P=0.151). Post-operative IOP at 12 months was 14.09±3.1mmHg (95%CI 13.22-14.97) in mitomycin group, and 13.25±2.5 mmHg (95%CI 12.40-14.30) in ologen group (P=0.254).The mean number of medications was 0.36±0.68 in mitomycin group and 0.38+/-0.70 in ologen group at 12 months (P=0.91). Overall success was achieved in 98.1 % of patients in mitomycin group and 90 % of patients in ologen group at 12 months. No major sight-threatening complications were noted in any group. AS-OCT imaging at 12 months showed multiform reflectivity with multiple large cystic spaces in both groups, with good IOP control.

Conclusion:

Phacotrabeculectomy using Mitomycin C and Ologen implant resulted in similar morphologic and functioning blebs at one year with comparable efficacy in controlling intraocular pressure.

Long-term perimetric stabilization with a management algorithm of set target intraocular pressure in different severities of primary angle-closure glaucoma

Purpose

To evaluate long-term perimetric stabilization at set Target (IOPs) in primary angle-closure glaucoma with visual field defects.

Methods

Two hundred forty-eight eyes, of 124 primary angle-closure glaucoma (PACG) patients on medical treatment, and 124 eyes, of 95 patients after trabeculectomy performed at least 5 years prior were evaluated. One hundred eighty-five eyes had a follow-up of ≥10 years. Target IOPs for mild, moderate, and severe glaucomatous optic neuropathy were set at ≤18, ≤15, and ≤12 mmHg, respectively. Progression was evaluated by event-based changes on guided progression analysis. Primary outcome measure was therapy required to achieve individualized Target IOP. Secondary outcome measure was assessment of perimetric change over time.

Results

Mean baseline IOP was 23.34 ± 6.16 mmHg in medically treated and 36.08 ± 9.73 mmHg in surgically treated eyes (P = 0.0001). All eyes with a baseline IOP of <25 mmHg were on medications alone, 65.33%, of those with a baseline IOP of 25-30 mmHg were on medications, while 34.67% required trabeculectomy. In total, 91.4% of eyes with a baseline IOP of >30 mmHg underwent a trabeculectomy for achieving Target IOP. Perimetric stabilization was achieved in 98.17% of PACG eyes. "Target" IOP was achieved for mild, moderate, and severe glaucomatous optic neuropathy, medically in 90.2, 73.9, and 29.7%, and surgery was required in 9.8, 26.1, and 70.3%, respectively. Overall analysis found that percentage reduction in IOP was significantly more after trabeculectomy than medical treatment, 64.16 ± 14.91 and 43.61 ± 13.73%, P = 0.0001. Decrease in IOP was significantly greater 5-9 years after trabeculectomy, in comparison to ≥10 years, P = 0.001.

Conclusion

Medications controlled IOP to "Target" in PACG eyes with mild and moderate glaucoma for over ≥10 years, when the baseline IOP off treatment was <30 mmHg. Trabeculectomy was necessary in PACG eyes having severe glaucomatous optic neuropathy, or with a baseline IOP of >30 mmHg to achieve Target IOP. These appropriate initial therapeutic interventions and Target IOPs are therefore suggested as a clinically validated algorithm of care for different severities of PACG.

Trabeculectomy with OloGen versus Mitomycin C for the Treatment of Silicone Oil-Induced Glaucoma

AIM

To compare the intraocular pressure-lowering effect and success rate of trabeculectomy with OloGen to that of trabeculectomy with mitomycin C (MMC) in cases of silicone oil-induced glaucoma.

MATERIALS AND METHODS

Forty eyes of forty patients with elevated intraocular pressure (IOP) after vitrectomy and silicone oil injection (followed by silicone oil removal) were assigned to two groups. Group A included 20 cases who underwent trabeculectomy with OloGen, while group B cases contained 20 cases undergoing trabeculectomy with MMC. The follow-up period was 24 months. Patients enrolled had IOP > 21 mmHg despite being on antiglaucoma medications.

RESULTS

The mean postoperative IOP reduction was lower in group A than in group B at all follow-up visits, but this difference was not statistically significant (p > 0.05). Moreover, group A and B patients were found to be similar as regards the need for postoperative antiglaucoma medications on all follow-up visits. The Kaplan-Meier survival analysis curves for the two groups revealed slightly higher success rates in group B than in group A. However, these differences were not statistically significant for both qualified success (IOP ≤ 21 mmHg with or without antiglaucoma medications) and complete success (IOP ≤ 21 mmHg without antiglaucoma medications). There was no significant difference in the postoperative complication rate between the two groups.

CONCLUSION

OloGen implant lowers IOP to a similar extent as MMC when combined with trabeculectomy for the treatment of silicone oil-induced glaucoma, and with comparable success rates. The rate of postoperative complications is similar for OloGen implantation and MMC.

The use of Ologen Collagen Matrix implants to treat ocular hypotony developing after trabeculectomy: A case series

PURPOSE

Late hypotony is an undesirable and challenging complication of glaucoma surgery. We describe our use of the Ologen Collagen Matrix to treat late hypotony developing after trabeculectomy.

STUDY DESIGN

A retrospective study performed at three eye surgery centers in Brazil.

PARTICIPANTS

Eighteen patients who underwent 19 eye surgeries.

INTERVENTION

Subconjunctival Ologen was implanted at the trabeculectomy sites to treat over-filtering or leaking blebs in patients experiencing late hypotony after trabeculectomy (obtained 6 months after glaucoma surgery). The primary outcome was the intraocular pressure (IOP); we gathered preoperative data records from 19 Ologen treated eyes and days 1, 7, 30, 60, and 180 postoperatively. The secondary outcomes included visual acuity and macular thickness measured via optical coherence tomography; we compared preoperative data to subsequent ones up to sixth-month-evolution.

RESULTS

Over the 6-month period, the IOP rose from 2.89 ± 1.59 mmHg preoperatively to 8.21 ± 3.46 mmHg (p = 0.0001). Visual acuity improved from 0.33 ± 0.29 to 0.21 ± 0.31 LogMar (p = 0.0013). Macular thickness fell from 325.62 ± 58.7 to 283.08 ± 47.35 µm (p = 0.0097). We encountered two complications: one related to suture dehiscence following an ocular trauma and one instance of transitory choroidal detachment.

CONCLUSION

Subconjunctival Ologen implants preserved bleb function and successfully treated post-trabeculectomy hypotony as revealed by data collected at the 6-month follow-up. Longer follow-up is necessary to confirm long-term efficacy and safety. There are no financial conflicts of interest to disclose.

Surgical and laser interventions for pseudoexfoliation glaucoma systematic review of randomized controlled trials

To assess the comparative effectiveness and safety of different surgical and laser techniques in people with pseudoexfoliation glaucoma (PXFG). We conducted a systematic review including randomized controlled trials (RCT) that compared any pair of surgical or laser treatment versus other type of intervention in PXFG. RCT were identified by a highly sensitive search of electronic databases and two individuals independently assessed trial eligibility, abstracted data and assessed risk of bias. We performed Bayesian Meta-Analysis when outcomes were comparable. The search strategy identified 6171 records. Six studies (262 subjects) were included. Two trials analyzed the same pair of surgical interventions comparing phacoemulsification as solo procedure or combined with trabecular aspiration and we performed meta-analysis. Other RCTs compared the following interventions: trabecular aspiration associated with phacoemulsification versus phacotrabeculectomy, non-penetrating deep sclerectomy associated or not with phacoemulsification, selective versus argon laser trabeculoplasty and one-site versus two-site phacotrabeculectomy. For IOP data, none of the trials reported a difference between pairs of surgical techniques, nor changes in visual acuity or number of post-operative medications. The overall risk of bias is moderate to high. There are no apparent differences in efficacy and safety, although with large uncertainty, between surgical or laser techniques for PXFG. Based on the low-quality evidence from the six studies included in this review, it is not possible to justify the preferential use of non-penetrating surgery, MIGS or trabecular aspiration (with or without cataract surgery) in PXFG. Further research is needed to determine the optimal management of this condition.

Cross-linked hyaluronic acid viscoelastic scleral implant in trabeculectomy

Purpose:

Patients with glaucoma undergoing trabeculectomy develop bleb cicatrix causing poor postoperative intraocular pressure (IOP) control and low success rates. Several approaches have been explored over the years for better outcomes. This study assesses the safety, efficacy, and outcome of trabeculectomy with HealaFlow^® (Anteis S. A, Geneva, Switzerland), a high-molecular-weight cross-linked hyaluronic acid viscoelastic gel, and comparing it with the antimetabolite Mitomycin-C (MMC).

Methods:

A prospective, interventional, case-controlled study conducted at a tertiary care hospital in Southern India on 60 eyes of patients requiring trabeculectomy divided in two groups – HealaFlow scleral implant and adjuvant low-dose MMC (0.1 mg/mL). Postoperative IOP reduction along with bleb morphology was assessed over follow-up at 1 week, 1 month, 3 months, 6 months, and 12 months.

Results:

Preoperatively IOP in the two groups was statistically similar. Postoperative IOP on day 1 had statistically significant reduction in both groups with greater reduction in MMC group. However, by 12 months, the IOP reduction was statistically similar in both groups, i.e., 46.24% (to 11.04 ± 2.55 mmHg) and 54.47% (to 11.99 ± 3.37 mmHg) in HealaFlow^® group and MMC group, respectively (P > 0.05). The bleb morphologies were similar and complications were seen equally, which resolved by 4 weeks. A complete success rate of 89.29% and a qualified success rate of 10.71% were observed equally in both groups.

Conclusion:

Absorbable biosynthetic cross-linked hyaluronic acid and low-dose MMC are equally safe and efficacious in trabeculectomy with significant IOP reduction and good bleb morphology. Therefore, it is a novel substitute for MMC.

Trabeculectomy in pregnancy: Case studies and literature review

Glaucoma management during pregnancy is a challenge for the patient and doctor. During pregnancy, the intraocular pressure (IOP) decreases. However, some women with preexisting glaucoma have elevated IOP requiring enhanced medical treatment. Glaucoma refractory to medical treatment combined with disease progression may necessitate laser trabeculoplasty or surgical intervention. Surgery during pregnancy has potential risks for both the mother and fetus. The challenges include problems with anesthesia, positioning for surgery, difficulties in the surgical procedure, potential risk with antimetabolites, and concerns with the management of postoperative complications. We report two case scenarios that highlight the challenges associated with trabeculectomy in pregnant women and the modifications that can be adopted to improve safety and the efficacy of glaucoma filtering surgery during pregnancy.

Ologen augmentation of Ahmed glaucoma drainage devices in pediatric glaucomas

Background

Limited data exists on the effectiveness of the collagen matrix, Ologen, on increasing Ahmed glaucoma valve (AGV) success in childhood glaucomas.

Methods

Ocular examination and surgical details of pediatric patients who underwent AGV placement ± Ologen augmentation between 2012 and 2020. Complete success was defined as intraocular pressure (IOP) between 5 and 20 mmHg without glaucoma medications and additional IOP-lowering surgeries. Qualified success was defined as above, except IOP control maintained with or without glaucoma medications.

Results

Twenty-two eyes of 16 patients underwent AGV placement of which 6 eyes had Ologen-augmentation (OAGV) and 16 eyes had conventional surgery (CAGV). Average age was 6.4 ± 5.1 years with 4.2 ± 2.5 follow-up years. There was no difference in age, number of previous surgeries, and preoperative IOP and glaucoma medications. At final follow-up, success rate was 100% (5 eyes complete, 6 eyes qualified) in the OAGV group compared to 31% (0 eyes complete, 5 eyes qualified) in the CAGV group. One and two-year survival rates were 100% for OAGV compared to 62 and 38% for CAGV. Postoperative IOP was significantly lower at 1-month and final follow-up (p = 0.02) as was the number of glaucoma medications at 3, 6, 12-months and final follow-up (p < 0.05) in the OAGV group.

Conclusions

Ologen-augmentation increased the success and survival rates of AGVs in childhood glaucomas. Further, Ologen mitigated the hypertensive phase and decreased medication dependency. Longer follow-up with a greater number of eyes is required to fully evaluate the effectiveness of OAGV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01827-4.

Experimental models of glaucoma filtration surgery

Glaucoma filtration surgery plays an important role in achieving intraocular pressure (IOP) reduction in patients who have high IOP despite maximum medical therapy. Preclinical experimental models of glaucoma filtration surgery contribute a great deal to our knowledge of the wound healing processes that predispose to scarring and may lead to poor outcomes. However, this research needs to be interpreted in the light of the specific study design, animal model and methods used. We review the existing literature addressing various models of experimental glaucoma filtration surgery, discuss the considerations in assessing these models and describe future steps in evaluating potential therapeutics and bleb characteristics that could impact translational research in this field.

Outcomes of trabeculectomy with polyvinylpyrrolidone collagen versus mitomycin in primary open angle glaucoma. 36-month follow-up

PURPOSE

Describe and compare the effects of intraoperative application of Polyvinylpyrrolidone Collagen (PVP) versus Mitomycin C (MMC) on the pattern of change in mean IOP reduction and mean number of medications over 36-months follow-up in patients with primary open angle glaucoma (POAG) undergoing trabeculectomy.

METHODS

Prospective, randomized, comparative study. Twenty-six eyes of 26 patients with POAG and no previous incisional glaucoma surgery underwent trabeculectomy and were randomized to PVP or MMC and completed a 36-month follow-up. Main outcome measures were IOP and number of glaucoma medications. Multivariate longitudinal analysis was performed by fitting a linear trend model adjusting for baseline response for the IOP outcome and a log-linear regression model with within-subject associations for the number of hypotensive medications outcome. Sensitivity analysis was performed to assess lower and higher order polynomial trends over time in IOP.

RESULTS

The univariate analysis revealed that the mean IOP reduction from baseline to 36 months was 7.62mmHg (3.05; 12.18) in the MMC group and 8.15mmHg (-0.64; 16.95) in the PVP group. Mean percentage IOP reduction from baseline was 37.09% (15.93; 58.17) and 36.08% (5.16; 67.20) in the PVP group. Mean change in number of medications from baseline to 36 months was -0.92 medications (-3.38; +1.54) for the MMC group and -1 medication (-3.12; +1.12) for the PVP group. Both groups had a statistically significant decline in mean IOP over the follow-up period (p<0.001) but there was no discernible difference between the two exposure groups in the rate of change in IOP (p=0.5975). Sensitivity analysis showed that a linear trend model is adequate to describe the IOP reduction over the follow-up period. Both groups had a statistically significant change in the number of hypotensive medications used between baseline and month 36 (p<0.05) but there was no discernible difference between exposure groups (p=0.2917). Both the PVP and MMC groups showed an initial reduction in number of medications until month 12 and a relatively linear increase towards month 36. A longer follow-up may be warranted to reveal differences in the number of medications between the two exposure groups. Postoperative complications were less frequent in the PVP group.

CONCLUSIONS

The use of PVP during trabeculectomy achieves and maintains a statistically significant IOP reduction from baseline to 36 months and decreases the number of glaucoma medications. Secondary outcome measures showed a lower incidence of adverse events in the PVP group.

Surgical management of complicated inflammatory glaucoma

Case report: We report a case of a 26-year-old woman with a previous history of complicated ulcerative colitis, as well as multiple episodes of recurrent anterior uveitis in control with adalimumab and methotrexate, who develops ocular hypertension refractory to topical treatment. The implant of an EXPRESS^® is proposed, but in the immediate post-operative period, the implant causes atalamia and does not achieve the correct control of intraocular pressure. A XEN^® stent was implanted. Due to failure, it was decided to remove the stent and to release a subconjunctival fibrosis that had formed at the subconjunctival portion of the XEN^®, in association with coating by an Ologen^® collagen matrix, which led to an improvement of the results. Conclusions: The surgical management of inflammatory glaucoma is complex in young patients with a scar component. The new minimally invasive techniques are effective in cases refractory to topical treatment, whose characteristics prevent the use of conventional ones.

The role of mitomycin C and porcine extracellular matrix in phacotrabeculectomy

PURPOSE

To compare between mitomycin C alone, porcine extracellular matrix alone, and combined low dose mitomycin C with porcine extracellular matrix in term of efficacy and safety in phaco-trabeculectomy surgery.

STUDY DESIGN

Prospective comparative.

METHODS

Sixty eyes of 60 patients complaining of primary open angle glaucoma and cataract, undergoing phaco-trabeculectomy, were distributed into three groups: group I: surgery was augmented with mitomycin C, group II with porcine extracellular matrix, and group III with porcine extracellular matrix combined with low dose mitomycin C. Intraocular pressure was evaluated, postoperatively, at day 1, week 1, and 1, 3, 6, 9, and 12 months. Bleb vascularity, pre- and post-operative intraocular pressure lowering medications, success of IOP control and complications were also evaluated.

RESULTS

After 12 months, the mean preoperative intraocular pressure (mm Hg) improved from 30.85 ± 4.7, 33.8 ± 4.2, and 31.05 ± 5.4 mm Hg, in groups I, II, and III respectively, to 13.8 ± 4.7 (55.2%), 15.2 ± 4.8 (55%), and 13 ± 4.9 (58.1%) (p > 0.05). Success of IOP control, postoperative IOP lowering medications and complications were comparable (p > 0.05). Bleb vascularity was significantly different (p < 0.05).

CONCLUSION

Mitomycin C, porcine extracellular matrix and their combination are equally effective in phacotrabeculectomy.

Does TRABECULECTOMY meet the 10-10-10 challenge in PACG, POAG, JOAG and Secondary glaucomas?

PURPOSE

Evaluation of the intraocular pressure (IOP) lowering efficacy of trabeculectomies over > 10 years and their ability to stabilize glaucomatous optic neuropathy.

METHODS

In total, 181 eyes (136 patients), which underwent trabeculectomy (10 min surgery) at least 10 years prior and were on regular follow-up, were evaluated. Qualified/complete success was taken as criteria A: IOP ≤ 12 mmHg, B: IOP ≤ 15 mmHg and C: IOP ≤ 18 mmHg, with all > 5 mmHg, with/without medications. Target IOP in advanced glaucoma is about 10 mmHg, therefore trabeculectomy 10-10-10 challenge!

RESULTS

The mean age of patients was 46.32 ± 11.50 years. Absolute success was 50.27%, 54.14% and 59.66% according to criteria A, B and C at last follow-up, while qualified success was 70.11%, 81.77% and 96.13%. An IOP of ≤ 12 mmHg was noted in 34, 64.15%, PACG eyes, 14, 73.68%, POAG, 15, 65.22%, JOAG and 64, 74.42%, secondary glaucoma eyes. The reduction in IOP overall was 64.83 ± 16.80% at last review and was 59.47 ± 16.07% in PACG, 62.40 ± 17.72% in POAG, 71.89 ± 8.50% in JOAG and 67.74 ± 18.10% in secondary glaucoma eyes. "Target" IOP was achieved in 97.29% of early glaucoma, 85.71% moderate glaucoma and 70% severe glaucoma eyes. 97.24% of patients were perimetrically stable. 2.21% of eyes post-trabeculectomy had a shallow anterior chamber needing surgical intervention. Visual acuity was maintained or better in 93.92% of patients, with a cataract surgery performed in 6.63% eyes. A repeat trabeculectomy was performed in 3.31% of eyes.

CONCLUSION

Trabeculectomy 10-10-10 is achievable in the long term, with few complications or repeat surgical interventions in the majority of POAG, PACG, JOAG and secondary glaucomas. Therefore, trabeculectomy should not be relegated to a last resort, but should be undertaken as soon as possible, if medical therapy is inadequate, unaffordable or compliance is an issue.

Phacotrabeculectomy using collagen matrix implant (Ologen® ) versus mitomycin C: a prospective randomized controlled trial

PURPOSE

To compare the efficacy and safety of collagen matrix implant (Ologen^® ; OLO) with mitomycin C (MMC) in phacotrabeculectomy.

METHODS

Prospective, single-centre, nonblinded, randomized controlled trial. A total of 53 eyes of 45 patients were enrolled in the study protocol with 27 eyes randomly assigned to OLO and 26 to MMC. The follow-up was 12 months. The primary outcome measure was mean change from baseline intraocular pressure (IOP) in both groups after 12 months. The secondary outcome measures were cumulative success rates at 12 months with Kaplan-Meier analysis, change in number of medications, change in best corrected visual acuity (BCVA), and bleb morphology assessed using Moorfields Bleb Grading System and anterior segment swept-source optical coherence tomography.

RESULTS

The mean IOP decreased from 26.4 ± 6.1 mmHg to 13.7 ± 3.8 in the OLO group and from 23.4 ± 3.6 mmHg to 13.3 ± 2.8 in the MMC group at 1 year without significant intergroup differences. At 1 year, the overall success rates were 92.6% and 92.3% in the OLO and MMC groups, respectively. There were no significant differences in the overall success rates, BCVA, number of medications, morphology of the filtering blebs and rate of complications at the end of the follow-up.

CONCLUSION

Ologen (OLO) provides similar surgical outcomes in phacotrabeculectomy compared with adjunctive MMC. It may be a new, safe and effective alternative to MMC for combined phacoemulsification and trabeculectomy surgery.

Efficacy of collagen matrix implant on adhesions in restrictive strabismus: An experimental study in a rabbit model

PURPOSE

To determine the efficacy of a biodegradable collagen matrix implant (Ologen, Aeon Astron Europe BV, Leiden, the Netherlands) in reducing adhesions in a rabbit model of restrictive strabismus.

METHODS

A prospective, masked-observer, controlled experimental study was performed. Sixty superior rectus muscles of 30 rabbits were resected and Marlex mesh was fixed beneath the resected muscle using nonabsorbable suture. Forty eyes underwent one of two different procedures; the resected muscle was wrapped with preserved human amniotic membrane (AM group) or Ologen (Ologen group). Randomly selected 20 eyes served as controls. Eyes were enucleated at 4 weeks after surgery to measure the severity of adhesion using a push pull gauge. Histopathological examination was performed.

RESULTS

At postoperative week four, the average tensile strength of the myoscleral adhesion was significantly lower in the Ologen group (151.8 ± 42.7 gram force) compared to controls (347.9 ± 68.6 gram force) and AM group (193.0 ± 44.3 gram force) (p < 0.001 and p = 0.045, respectively). Ologen group showed significantly lower degree of acute inflammation, chronic inflammation and rectus muscle fibrosis compared with controls (all p < 0.01). The degree of chronic inflammation was significantly lower in the Ologen group compared with AM group (p = 0.012).

CONCLUSION

Compared to amniotic membrane, Ologen is more effective in reducing mesh-related extraocular muscle adhesions in a rabbit model of restrictive strabismus.

Five Years' Outcomes of Trabeculectomy with Cross-linked Sodium Hyaluronate Gel Implantation for Chinese Glaucoma Patients

Background:

Trabeculectomy is the most efficient surgical treatment. Prevention failure of bleb cicatrix would lead to unsatisfactory postoperative intraocular pressure (IOP) controlling and unsatisfactory success rate. The aim of this study was to evaluate the 5-year outcomes of trabeculectomy with a cross-linked sodium hyaluronate gel implantation for Chinese glaucoma patients.

Methods:

This is a prospective, case-controlled study. Patients who were to be applied first-time trabeculectomy in the Department of Ophthalmology of Peking University Third Hospital between 2010 and 2012 were included in the study. Totally, 60 eyes were randomly assigned to the trabeculectomy group (TA group) or the trabeculectomy with cross-linked sodium hyaluronate gel implantation group (TH group). Follow-up was finished at 1 week, 1 month, 3 months, 1 year, 3 years, and 5 years after the operation. The statistical index of demographic data, IOP, bleb shape, and any complications or medications or surgical procedures were recorded and assessed by SPSS 19.0 software through independent t-test, one-way analysis of variance (ANOVA) and Pearson's Chi-square test, respectively.

Results:

The baseline IOP was comparable between the two groups (t= −1.00, P= 0.32) while the postoperative IOP was significantly lower in the TH group at 1, 3 and 5 years' time points (P = 0.00, P= 0.01 and P = 0.01, respectively). According to the Indiana Bleb Appearance Grading Scale, the height and extent of bleb were better in the TH group at all follow-up time points (P < 0.05), however, the comparison of bleb vascularity showed no statistical difference (P > 0.05). TA group had a higher percentage of complications (13% vs. 3%) compared to TH group; however, there was no statistical difference in the comparison of each statistical item (P > 0.05, respectively). The complete success at 5 years was higher in the TH group than that in the TA group (78% vs. 54%, P = 0.03).

Conclusion:

Our results suggested that implantation of cross-linked sodium hyaluronate gel with trabeculectomy was more efficient and would improve the prognosis of glaucoma patients.

[Glaucoma surgery: from traditional filtration techniques to modern principles of bioengineering]

The article reviews the history of glaucoma surgery and analyses the connection between the accumulation of knowledge on glaucoma progression and the emergence of effective surgical treatment methods based on glaucoma pathogenesis. It also describes modern principles of preventing filtering bleb scarring. Particular attention is devoted to biodegradable collagen matrix implants.

Outcome of trabeculectomy with Ologen versus Mitomycin C: A comparative prospective study in Bangladesh

AIMS:

To compare the efficacy and safety of trabeculectomy with Ologen versus Mitomycin C in primary glaucoma.

MATERIALS AND METHODS:

This is a prospective study of patients aged 18 years and above, diagnosed with primary glaucoma randomised to having trabeculectomy with Ologen or Mitomycin C. The primary outcome measure was success of trabeculectomy defined as intraocular pressure >5 mmHg but ≤21 mmHg. Complete success was defined as intraocular pressure achieved without anti-glaucoma medication and qualified success was defined as intraocular pressure achieved with additional anti-glaucoma medication.

RESULTS:

At the end of 12 months follow-up, the postoperative mean intraocular pressure in the Ologen group was 12.8 ± 1.6 mmHg and 13.4 ± 2.2 mmHg in the Mitomycin C group. The Ologen group achieved complete success in 86.5% and qualified success in 13.5% of the patients, while the Mitomycin C group achieved complete and qualified success in 85.5% and 14.5%, respectively. There was no statistically significant difference in the success rate of both the groups ( p = 0.57). Furthermore, no significant intraocular pressure difference was noted between the two groups at the end of 12 months follow-up ( p = 0.14).

CONCLUSION:

Trabeculectomy augmented with Ologen appeared to be as successful and safe as trabeculectomy augmented with Mitomycin C, with no reported adverse reaction to Ologen.

Simplifying "target" intraocular pressure for different stages of primary open-angle glaucoma and primary angle-closure glaucoma

Lowering of intraocular pressure is currently the only therapeutic measure for Glaucoma management. Many longterm, randomized trials have shown the efficacy of lowering IOP, either by a percentage of baseline, or to a specified level. This has lead to the concept of 'Target" IOP, a range of IOP on therapy, that would stabilize the Glaucoma/prevent further visual field loss, without significantly affecting a patient's quality of life. A clinical staging of Glaucoma by optic nerve head evaluation and perimetric parameters, allows a patient's eye to be categorized as having - mild, moderate or severe Glaucomatous damage. An initial attempt should be made to achieve the following IOP range for both POAG or PACG after an iridotomy. In mild glaucoma the initial target IOP range could be kept as 15-17 mmHg, for moderate glaucoma 12-15 mmHg and in the severe stage of glaucomatous damage 10-12 mmHg. Factoring in baseline IOP, age, vascular perfusion parameters, and change on perimetry or imaging during follow up, this range may be reassessed over 6 months to a year. "Target" IOP requires further lowering when the patient continues to progress or develops a systemic disease such as a TIA. Conversely, in the event of a very elderly or sick patient with stable nerve and visual field over time, the target IOP could be raised and medications reduced. An appropriate use of medications/laser/surgery to achieve such a "Target" IOP range in POAG or PACG can maintain visual fields and quality of life, preventing Glaucoma blindness.

Trabeculectomy with Ologen implant versus mitomycin C in congenital glaucoma secondary to Sturge Weber Syndrome

AIM

To compare the efficacy and safety of collagen matrix implant [Ologen (OLO) implant] versus mitomycin C (MMC) with subscleral trabeculectomy (SST) for the surgical treatment of congenital glaucoma (CG) in Sturge-Weber Syndrome (SWS).

METHODS

A prospective comparative randomized study of 20 eyes of 16 patients with CG associated with SWS was divided into two groups. The first group (MMC Group) included 10 eyes that were subjected to SST with MMC. The second group (OLO Group) included 10 eyes that were subjected to trabeculectomy with a collagen matrix implant (OLO implant). Postoperative evaluation included intraocular pressure (IOP) level, bleb evaluation, complications, and the need for further medication or surgical intervention.

RESULTS

The mean preoperative IOP was 29±3.16 mm Hg in MMC and 29.8±3.08 mm Hg in OLO eyes. Mean 12-month percentage reduction in IOP was significant in both groups (57.9% and 56.3%). At the end of the 12 postoperative follow-up month, in the MMC Group, 80% of eyes achieved the complete success, 20% of eyes had qualified success with no failed surgery in comparison to OLO Group which 70% of eyes achieved the complete success, 20% of eyes had qualified success with 10% failed surgery. In terms of complications, the MMC Group had a higher rate of complications than the OLO Group in the form of thin polycystic bleb in 6 eyes (60%), blebitis in only one eye (10%) treated with topical antibiotics, shallow anterior chamber in two eyes (20%).

CONCLUSION

This study proves that the use of a collagen matrix implant yields equally effective results as MMC when combined with trabeculectomy for the treatment of CG in SWS. Furthermore, OLO implantation is safe and has low incidences of complications.

Improving Glaucoma Surgical Outcomes with Adjunct Tools

Conventional glaucoma surgeries, such as trabeculectomy and glaucoma drainage device (GDD) surgery, have been enhanced by surgeons to improve outcome and decrease complications. Over the last two decades, adjuncts, such as collagen matrix implants, fibrin adhesives, and amniotic membrane transplantation (AMT) have been found to be effective in modulating fibrosis and scarring during the wound-healing process, reducing postoperative inflammation, and repairing bleb leakage or conjunctival erosion. The use of these tools provides several advantages when used in trabeculectomy, GDD surgery, and surface reconstruction associated with glaucoma surgery complications. Their use will be discussed in this review. How to cite this article: Lu LJ, Hall L, Liu J. Improving Glaucoma Surgical Outcomes with Adjunct Tools. J Curr Glaucoma Pract 2018;12(1):19-28.

[Revision after filtration surgery]

BACKGROUND

In contrast to all other glaucoma surgeries, filtration surgery is associated with biomicroscopically visible wound healing, which enables the surgeon to perform revision surgeries if necessary.

OBJECTIVES

The aim of this review is to provide general considerations and to give a structured overview about bleb revisions after trabeculectomy.

MATERIALS AND METHODS

The different revision techniques are explained in detail and in the context of perioperative management.

RESULTS

Preoperative preparation and modifications of the surgical techniques reduce the incidence of postoperative revisions. The site of the fibrosis defines the revision technique (bleb needling, needle revision, bleb revision with reopening). The increased percolation rate of aqueous humor in postoperative hypotony contributes to fibrosis and may lead to maculopathy, choroidal effusion, and suprachoroidal hemorrhage.

DISCUSSION

Discontinuing administration of local medication and pretreatment with steroids without preservative for at least one week prior to surgery increase surgical success of trabeculectomy and reduce the incidence of postoperative revisions. Postoperative management after filtration surgery should be performed after consulting the surgeon. The primary endpoint of trabeculectomy is an intraocular pressure between 8 and 12 mm Hg without local antiglaucomatous medication. In postoperative hypotony revisions should be done earlier and based on the pathological findings.

Viscocanalostomy combined with trabeculotomy and mitomycin C in the treatment of primary congenital glaucoma

AIM

To evaluate the long-term outcome of viscocanalostomy combined with trabeculotomy and mitomycin C in the treatment of primary congenital glaucoma.

METHODS

This is a retrospective study. Forty-two eyes of 26 patients with primary congenital glaucoma were enrolled. Intraocular pressure (IOP), corneal diameter (mm) and cup/disc (C/D) were measured before and after the surgery respectively. Follow-up period was 30mo.

RESULTS

The mean preoperative IOP was 30.6±7.35 mm Hg. Of the 42 eyes, 2 eyes were required conversion to trabeculectomy for the absence of Schlemm's canal. Of remained 40 eyes, 38 eyes (95%) achieved successful IOP control. The average postoperative IOP was 11.69±4.18 mm Hg at 12mo. The mean reduction was 18.91 mm Hg (P<0.0001). Eighteen (75%) eyes presented a reduction in corneal diameter, and 25 (62.5%) eyes presented a C/D ratio reversal after the surgery. There was no serious complication in any patients over the follow-up period.

CONCLUSION

Viscocanalostomy combined with trabeculotomy and mitomycin C is useful in the management of primary congenital glaucoma.