Bleb vascularity following post-trabeculectomy subconjunctival bevacizumab: a pilot study

Intravitreal bevacizumab improves trabeculectomy survival at 12 months: the bevacizumab in trabeculectomy study-a randomised clinical trial

AIMS

To evaluate the effect of an intraoperative dose of intravitreal bevacizumab (Avastin) on surgical success following trabeculectomy with mitomycin-C (MMC) over 12 months.

METHODS

A single centre, parallel, double-blinded randomised, placebo-controlled trial recruiting patients requiring trabeculectomy for progressing glaucoma. Patients were randomised to intravitreal bevacizumab or placebo.

MAIN OUTCOME MEASURE

The primary outcome of treatment success was defined by 'complete success' when intraocular pressure (IOP) remained less than a predefined target IOP without the requirement of topical medication, or 'qualified success' where topical medication was required to meet the predefined target IOP threshold. Secondary outcomes included the need for subsequent IOP-lowering interventions, and structural parameters associated with bleb function.

RESULTS

From 131 patients randomised to bevacizumab (n=65) or placebo (n=66), 128 patients completed 12 months of follow-up (98%). At 12 months, success rates were higher in the bevacizumab group (complete success: 94% vs 83%; p=0.015; qualified success: 98% vs 90%; p=0.033). Within the placebo group, the requirement for topical therapy was higher at 6 months (p=0.045) and 12 months (p=0.045), and the requirement for bleb needling was higher at 1 month (p=0.035). Blebs within the bevacizumab group were larger at 1 month (p<0.001) and demonstrated less vessel inflammation (p<0.0001).

CONCLUSION

Bevacizumab given as a single intravitreal dose during trabeculectomy with MMC resulted in improved surgical success as 12 months. Furthermore, bevacizumab was associated with a significant reduction in the need for additional medication or further surgery to achieve target IOP. Bevacizumab was also associated with larger blebs that were less inflamed and required fewer subsequent interventions.

TRIAL REGISTRATION NUMBER

ACTRN12614000375651.

Assessing safety and success after using bevacizumab, 5-fluorouracil or placebo in primary trabeculectomy. A Prospective Randomized placebo controlled 1-Year Follow-up Study

PURPOSE

The aim of this study was to determine whether glaucoma patients after trabeculectomy could benefit more from subconjunctival injections of bevacizumab than 5-FU or placebo.

METHODS AND RESULTS

Fifty-one eyes of 51 patients were recruited for primary MMC (0.2mg/ml for 1 min) augmented trabeculectomy. 17 patients were randomly assigned to receive 1.25mg (0.05ml) of bevacizumab augmentation, 21 patients were assigned to receive 0.1ml of 50mg/ml 5-FU and 13 patients were assigned to a control group receiving a normal saline injection as a placebo. Initial recruitment included 58 patients, but seven patients had to be excluded from the study for various reasons. Postoperative follow up of IOP and bleb characteristics was carried out at 1 day, 1 week, 3 weeks, 6 weeks, 6 months and 1 year after surgery. All analyses where carried out by two masked clinicians. IOP reduction was statistically significant (P < 0.05) across all three groups between baseline visit and final 1-year postoperative visit. There was no significant difference of the final average IOP values between the three groups. Bleb evaluation was made using the Moorfields bleb grading system (MBGS) after 1 year follow up. Central bleb area was statistically greater in the Bevacizumab group when compared with the 5-FU group but not with the placebo group. The vascularity of the central bleb was significantly different between the groups with the Bevacizumab group showing the least vascularity. Vascularity of the peripheral bleb was also decreased in the Bevacizumab group when compared with the placebo group but not with the 5-FU group.

CONCLUSION

The 12-month IOP results showed no significant differences between the groups of patients after Bevacizumab, 5-FU or placebo to augment primary MMC enhanced trabeculectomy. However, by the analysis of bleb morphology there was a significant difference in terms of central bleb area and vascularity.

[Monocentric, Retrospective, Comparative Study of the Safety and Effectiveness of Wound Modulation with Bevacizumab after Combined Cataract Surgery with Implantation of the CyPass Stent]

BACKGROUND

Because of the known positive effect of bevacizumab (Avastin^®) on wound modulation in trabeculectomy, a retrospective study evaluated the safety and efficacy of wound modulation with Avastin following combined cataract surgery with CyPass stent.

METHOD

Retrospectively, the pre-, intra- and postoperative data (after three and six months) were collected from 484 eyes after combined surgery (n = 187 without Avastin, n = 297 with Avastin). The safety criteria were intraoperative complications and postoperative slit-lamp microscopic findings. Efficacy criteria were intraocular pressure (IOP) and number of IOP-lowering drugs.

RESULTS

With respect to age and sex distribution, early postoperative fibrin reaction, intraocular pressure and reduction in medication, the two groups (with and without Avastin) did not differ statistically significantly. However, iris tissue reactions were statistically significantly more frequently observed three months postoperatively in the control group than in the Avastin group (chi square test: p = 0.02, n = 47/128); there is a slight trend after six months towards less iris tissue reaction in the Avastin group (chi square test: p = 0.15, n = 45/125). Other trends in favour of the Avastin group were identified within the failure rate (2% compared to 6% at three months (chi square test: p = 0.103, n = 50/130) and 4 to 10% at six months (chi square test: p = 0.106, n = 50/130) and within the proportion of eyes without supplemental hypotensive medication, with 86 vs. 74% and 68 vs. 56% (chi square test: three months: p = 0.053; six months: p = 0.12; n = 50/130). In addition, 85% of the eyes in the Avastin group reached the postoperative pressure threshold of ≤ 21 mmHg without supplemental hypotensive medication three months postoperatively and 65% after six months compared to 74% (chi square test: p = 0.099, n = 50/130) and 54% (chi square test: p = 0.11, n = 50/130) in the control group.

CONCLUSION

The postoperative injection of Avastin into the anterior chamber is safe, reduces iris tissue reactions and improves efficacy up to six months postoperatively to a clinically limited extent.

Intracameral bevacizumab role in trabeculectomy: A 1-year prospective randomized controlled study

Purpose:

To evaluate the effect of intracameral Bevacizumab on trabeculectomy success rates.

Methods:

A prospective, randomized, interventional clinical trial. Patients with primary open-angle glaucoma were randomly assigned to two groups: trabeculectomy with mitomycin C and trabeculectomy with mitomycin C and intracameral bevacizumab. Complete success is defined as an intraocular pressure (IOP) reduction of at least 30% from baseline IOP to a measured pressure of between 5 and 18 mm Hg without the use of IOP lowering medications. Qualified success is defined as same achievement of reduced IOP, but with the use of IOP lowering medications. Overall success is defined as same achievement of reduced IOP with or without the use of IOP lowering medications.

Results:

Thirty-three patients in the mitomycin C group and 36 patients in the mitomycin C and bevacizumab group were included in final analyses. The IOP at presentation was 28.3 ± 8 and 28.4 ± 8.6 mm Hg, compared to 10.8 ± 3.4 and 12.3 ± 3.7 mm Hg at 12 months (p < 0.0001) for the mitomycin C group and the mitomycin C and bevacizumab group, respectively. Complete success at 12 months was achieved in 65% of the mitomycin C group compared to 60% of the mitomycin C and bevacizumab group (p = 0.77). Overall success was achieved in 82% compared to 80% of patients at 12 months (p = 0.78). Both groups showed a statistically significant reduction in IOP after 6 and 12 months (p ⩽ 0.001). There were no statistically significant differences in visual acuity and complications.

Conclusion:

Intracameral bevacizumab during mitomycin C trabeculectomy in patients with primary open-angle glaucoma apparently does not improve success rates. The adjuvant use of intracameral bevacizumab is therefore not justified.

Important Metabolites in Maintaining Folate Cycle, Homocysteine, and Polyamine Metabolism Associated with Ranibizumab Treatment in Cultured Human Tenon's Fibroblasts

The anti-fibrotic properties of ranibizumab have been well documented. As an antagonist to vascular endothelial growth factor (VEGF), ranibizumab works by binding and neutralizing all active VEGF-A, thus limiting progressive cell growth and proliferation. Ranibizumab application in ocular diseases has shown remarkable desired effects; however, to date, its antifibrotic mechanism is not well understood. In this study, we identified metabolic changes in ranibizumab-treated human Tenon's fibroblasts (HTFs). Cultured HTFs were treated for 48 h with 0.5 mg/mL of ranibizumab and 0.5 mg/mL control IgG antibody which serves as a negative control. Samples from each group were injected into Agilent 6520 Q-TOF liquid chromatography/mass spectrometer (LC/MS) system to establish the metabolite expression in both ranibizumab treated cells and control group. Data obtained was analyzed using Agilent Mass Hunter Qualitative Analysis software to identify the most regulated metabolite following ranibizumab treatment. At p-value < 0.01 with the cut off value of two-fold change, 31 identified metabolites were found to be significantly upregulated in ranibizumab-treated group, with six of the mostly upregulated having insignificant role in fibroblast cell cycle and wound healing regulations. Meanwhile, 121 identified metabolites that were downregulated, and seven of the mostly downregulated are significantly involved in cell cycle and proliferation. Our findings suggest that ranibizumab abrogates the tissue scarring and wound healing process by regulating the expression of metabolites associated with fibrotic activity. In particular, we found that vitamin Bs are important in maintaining normal folate cycle, nucleotide synthesis, and homocysteine and spermidine metabolism. This study provides an insight into ranibizumab's mechanism of action in HTFs from the perspective of metabolomics.

Combined Application of Bevacizumab and Mitomycin C or Bevacizumab and 5-Fluorouracil in Experimental Glaucoma Filtration Surgery

The present study aimed at observing the effect of a single subconjunctival injection of bevacizumab (BVZ) combined with 5-fluorouracil (5-Fu) or mitomycin C (MMC) on the antiscarring effect of glaucoma filtration surgery (GFS). The inhibitory effect of combined BVZ and 5-Fu in retinal pigment epithelial cells on vascular endothelial growth factor (VEGF) levels was demonstrated through in vitro experiments. Combined BVZ and 5-Fu and combined BVZ and MMC inhibited cell cycle, induced apoptosis, and inhibited human umbilical vein endothelial cell migration. Also, the cytotoxicity of combined BVZ and 5-Fu was lower. In animal experiments, the observation of filtering bleb survival, hematoxylin and eosin and Masson staining of filtering bleb scars, and mRNA expression levels of fibrosis markers in filtering blebs showed that combined BVZ and 5-Fu had a better antiscarring effect compared with single drugs; however, the antiscarring effect of combined BVZ and MMC was not significantly different from MMC. Therefore, the findings of this study provided more reference for the clinical use of adjuncts to inhibit scarring after GFS and helped understand the regulatory effect of combined anti-VEGF antibody BVZ and antimetabolites on wound healing more comprehensively.

Modulation of Fibroblasts in Conjunctival Wound Healing

Modulating conjunctival wound healing has the potential to improve outcomes after glaucoma filtration surgery and for several ocular disorders, including ocular cicatrial pemphigoid, vernal keratoconjunctivitis, and pterygium. Although anti-inflammatories and antimetabolites have been used with success, these nonspecific agents are not without their complications. The search for novel and more targeted means to control conjunctival fibrosis without such limitations has brought much attention to the regulation of fibroblast proliferation, differentiation, extracellular matrix production, and apoptosis. This review provides an update on where we stand with current antifibrotic agents and outlines the strategies that novel agents use, as they evolve from the bench to the bedside.

Use of Anti-VEGF Agents in Glaucoma Surgery

A number of antivascular endothelial growth factor agents are currently available to treat various ocular conditions. These agents have similar, but distinct, biologic qualities and have been explored in the management of neovascular glaucoma and in glaucoma surgery. Several different delivery methods are described, and because these medications are routinely given as intraocular injections, some benefits over traditional antifibrotic medications when used in glaucoma surgery are noted. These agents effectively induce regression of anterior segment neovascularization and facilitate initial surgical management of neovascular glaucoma, but the long-term outcome of this condition remains dependent on definitive management of the underlying process. Use in trabeculectomy or tube shunt procedures for other types of glaucoma has shown promise in modulating bleb morphology but has not yet been found to be as effective as traditional antifibrotic agents. There are reports of persistently raised intraocular pressure after repeated use of the anti-VEGF agents, possibly related to frequency of injection. These medications have wide application in the field of surgical glaucoma, but a definitive role has yet to be defined.

Suppression of Human Tenon Fibroblast Cell Proliferation by Lentivirus-Mediated VEGF Small Hairpin RNA

Purpose. The functions of vascular endothelial growth factor (VEGF) in scar formation after trabeculectomy were investigated in a human Tenon fibroblast cell line from glaucoma patients using lentivirus-mediated VEGF shRNA. Methods. Human Tenon fibroblast (HTF) cells were isolated from scar tissue of glaucoma patients during secondary surgery. Lentivirus-VEGF-shRNA was constructed and transfected into HTF cells. Subsequently, VEGF mRNA and protein expression were analyzed using quantitative RT-PCR and western blotting, respectively, and the effects of VEGF knockdown were analyzed. The inhibition of HTF proliferation was monitored according to total cell numbers using ScanArray. Results. Both mRNA and protein levels of VEGF were reduced by lentivirus-mediated VEGF-shRNA, and proliferation of HTF cells was inhibited. Conclusions. Primary cultures of human Tenon fibroblast (HTF) were established, and proliferation was decreased following inhibition of VEGF. VEGF may be a suitable therapeutic target for reducing scar tissue formation in glaucoma patients after filtration surgery.

Innovations and adaptations in trabeculectomy

PURPOSE OF REVIEW

This article examines the current literature reporting updates on trabeculectomy techniques, complications, and cost-effectiveness.

RECENT FINDINGS

Trabeculectomy continues to be the standard for glaucoma surgery when a low intraocular pressure is required. Recent publications describe technique modifications that successfully increase efficacy and lower complications. There is also an ongoing effort to define the role of trabeculectomy in the management of glaucoma from a cost and public health standpoint.

SUMMARY

The current literature continues to support the use of trabeculectomy as a method of lowering intraocular pressure in glaucoma management. Efficacy has been improved by ongoing surgical innovation, and reported complication rates are lower than those previously noted. Trabeculectomy has a favorable cost-benefit profile when compared with medical therapy or other surgical techniques. In spite of these ongoing changes, trabeculectomy appears to be decreasing in frequency in favor of newer surgeries and medications.

Wound Dehiscence and Device Migration after Subconjunctival Bevacizumab Injection with Ahmed Glaucoma Valve Implantation

Purpose:

To report a complication pertaining to subconjunctival bevacizumab injection as an adjunct to Ahmed Glaucoma Valve (AGV) implantation.

Case Report:

A 54-year-old woman with history of complicated cataract surgery was referred for advanced intractable glaucoma. AGV implantation with adjunctive subconjunctival bevacizumab (1.25 mg) was performed with satisfactory results during the first postoperative week. However, 10 days after surgery, she developed wound dehiscence and tube exposure. The second case was a 33-year-old man with history of congenital glaucoma and uncontrolled IOP who developed AGV exposure and wound dehiscence after surgery. In both cases, for prevention of endophthalmitis and corneal damage by the unstable tube, the shunt was removed and the conjunctiva was re-sutured.

Conclusion:

The potential adverse effect of subconjunctival bevacizumab injection on wound healing should be considered in AGV surgery.

VEGF inhibitors in glaucoma surgery

Vascular endothelial growth factor (VEGF) is a signaling protein, that controls vasculogenesis, angiogenesis, vascular support and stimulates permeability of small blood vessels. The following isoforms are presently known: VEGF-A, VEGF-B, VEGF-C, VEGF-В and PGF. VEGF-A, that regulates neoangiogenesis and fibroblast formation, is thought to play the most important role in human organism. Increased expression of VEGF may lead to development and aggravation of pathological conditions including oncology. The article presents a review of preclinical and clinical studies of the main VEGF-inhibitors - bevacizumab and ranibizumab, as well as a brief account on other existing medications of this group. It describes ophthalmological indications for the use of antiangiogenetic agents, as well as the ways of their possible off-label use. The review presents investigations of intravitreal and intracameral injections of VEGF-inhibitors in patients with retinal, chorioidal, iris, and anterior chamber angle neovascularization. It gives examples of successful anti-VEGF use before Ahmed glaucoma valve drainage device implantation and in cases of neovascular glaucoma, induced by radiation therapy for intraocular tumors. Tenon’s capsule’s fibroblasts take part in the process of postoperative wound healing and scarring. According to the latest research, this process could be modulated by angiogenesis inhibitors. This review also recounts the use of anti-angiogenic agents to inhibit postoperative fibroblast proliferation, when used as monotherapy, or as an adjuvant to mitomycin С or 5-fluorouracil. It reviews the research on VEGF-inibitors use in combination with postoperative needling.

Anti-vascular endothelial growth factor for control of wound healing in glaucoma surgery

BACKGROUND

Trabeculectomy is performed as a treatment for glaucoma to lower intraocular pressure (IOP). The surgical procedure involves creating a channel through the wall of the eye. However scarring during wound healing can block this channel which will lead to the operation failing. Anti-vascular endothelial growth factor (VEGF) agents have been proposed to slow down healing response and scar formation.

OBJECTIVES

To assess the effectiveness of anti-VEGF therapies administered by subconjunctival injection for the outcome of trabeculectomy at 12 months follow-up and to examine the balance of benefit and harms when compared to any other anti-scarring agents or no additional anti-scarring agents.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2015, Issue 10), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2015), EMBASE (January 1980 to November 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 12 November 2015.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of anti-VEGF therapies administered by subconjunctival injection compared to any other anti-scarring agents or no additional anti-scarring agents (no treatment or placebo) in trabeculectomy surgery.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcome was successful trabeculectomy at 12 months after surgery which was defined as achieving a target IOP (usually no more than 21 mm Hg) without any additional intervention. Other outcomes included: qualified success (achieving target IOP with or without additional intervention), mean IOP and adverse events.

MAIN RESULTS

We included five RCTs (175 participants, 177 eyes) that met the inclusion criteria in this review.One trial conducted in Iran (37 participants, 37 eyes) compared anti-VEGF (bevacizumab 0.2 mg) versus control (sham injection) in people with refractory glaucoma. We judged this study to be at low risk of bias.The primary outcome of this review was not reported; mean IOP at three months was 15.1 mm Hg (standard deviation 1.0) in both anti-VEGF and control groups.Four trials compared anti-VEGF to mitomycin C (MMC) (138 particpants, 140 eyes). These studies were conducted in India, Iran, Turkey and the USA. The anti-VEGF agent used in these four trials was bevacizumab 2.5 mg (two trials), bevacizumab 1.25 mg three times and ranibizumab 0.5 mg. Two trials were at high risk of bias in two domains and one trial was at high risk of bias in four domains.Only one of these trials reported the primary outcome of this review (42 participants, 42 eyes). Low quality evidence from this trial showed that people receiving bevacizumab 2.5 mg during primary trabeculectomy were less likely to achieve complete success at 12 months compared to people receiving MMC but the confidence interval (CI) was wide and compatible with increased chance of complete success for anti-VEGF (risk ratio (RR) 0.71, 95% CI 0.46 to 1.08), Assuming that approximately 81% of people receiving MMC achieve complete success, the anticipated success using anti-VEGF agents would be between 37.2% and 87.4%. The same trial suggested no evidence for any difference in qualified success between bevacizumab and MMC (RR 1.00, 95% CI 0.87 to 1.14, moderate quality evidence). Two trials of primary trabeculectomy provided data on mean IOP at 12 months; one trial of bevacizumab 2.5 mg and one trial of ranibizumab 0.5 mg. Mean IOP was 1.86 mm Hg higher (95% CI 0.15 to 3.57) in the anti-VEGF groups compared to the MMC groups (66 people, low quality evidence). Data were reported on wound leak, hypotony, shallow anterior chamber and endophthalmitis, but these events occurred rarely and currently there are not enough data available to detect any differences, if any, between the two treatments.

AUTHORS' CONCLUSIONS

The evidence is currently of low quality which is insufficient to refute or support anti-VEGF subconjunctival injection for control of wound healing in glaucoma surgery. The effect on IOP control of anti-VEGF agents in glaucoma patients undergoing trabeculectomy is still uncertain, compared to MMC.Further RCTs of anti-VEGF subconjunctival injection in glaucoma surgery are required, particularly compared to sham treatment with at least 12 months follow-up.

Efficacy of Adjunctive Subconjunctival Bevacizumab on the Outcomes of Primary Trabeculectomy With Mitomycin C: A Prospective Randomized Placebo-controlled Trial

Purpose:

To evaluate the efficacy of subconjunctival bevacizumab (ScB) as adjuvant therapy to primary trabeculectomy with mitomycin C (MMC) in primary open-angle glaucoma.

Materials and Methods:

Forty-six eyes of primary open-angle glaucoma patients were randomized to receive ScB (1.25 mg/0.05 mL) injections (the MMC+ScB group) at the end of the operations, or sham-treated controls (the MMC group). Intraocular pressure (IOP) was the primary outcome and secondary outcomes included bleb appearance, visual acuity, number of medications, complications, and proportion of eyes achieving successful outcomes at the 12-month follow-up.

Results:

Of 39 eyes, 20 eyes from the MMC+ScB group, and 19 eyes from the MMC group completed the follow-up. The mean postoperative IOP was 15.5±4.1 mm Hg in the MMC+ScB group (P<0.01; 40% reduction), and 14.7±4.3 mm Hg in the MMC group (P<0.01; 44% reduction). The differences in IOPs, at all follow-up visits, were not significant (P>0.05). The mean bleb vascularity score, at 1 month, in the MMC+ScB group was lower than the MMC group (1.55±0.51 vs. 2.26±0.6, respectively, P=0.01), but was not retained at follow-ups. The success rates at 12 months after surgery were 85% in the MMC+ScB group and 89.5% in the MMC group (P=0.53). The cumulative probabilities of surgical success were 80% and 73.7% in the MMC+ScB and in the MMC group, respectively (P=0.52).

Conclusion:

Single adjunctive ScB injection did not appear to have an additive benefit on outcomes of MMC trabeculectomy, in terms of IOPs and success rates.

Modulation of wound healing in glaucoma surgery

Glaucoma is a neurodegenerative disease and is the second most important cause of irreversible blindness. Filtration surgery remains the most effective therapy to reduce intraocular pressure in glaucoma patients. The main determinant of long-term surgical success is the healing response. Excessive postoperative wound healing with subsequent fibrosis may lead to obstruction of the created channel which frequently results in early surgical failure and consequent progression of visual field loss. Preoperative use of antimitotics, such as mitomycin-C and 5-fluorouracyl, effectively improves surgery outcome. However, the use of these nonspecific antiproliferative agents can be associated with severe side effects. This review provides an overview of the most important efforts that have been made to explore novel, more specific, and safer agents to prevent glaucoma filtration failure and improve surgery outcome.

Time Heals All Wounds: Obstacles in Glaucoma Surgery from an Asian Perspective

Glaucoma is the leading cause of irreversible blindness worldwide and is a particular burden on the Asian population. Glaucoma surgeries such as trabeculectomy and glaucoma drainage implants are routinely performed to lower intraocular pressure (IOP) to prevent disease progression. However, scarring of the filtering bleb limits their long-term success and Asian eyes are more at risk. Although this is so, many existing studies have been done on Caucasian patients, but few have focused solely on Asian patients. Intraoperative anti-metabolites such as Mitomycin-C (MMC) and 5-Fluorouracil (5-FU) are the current mainstay of adjunctive treatments to reduce scarring, and in this review, we evaluate the evolution, benefits and side effects of these agents. Recently, newer methods of wound modulation including anti-vascular endothelial growth factor (VEGF) agents and collagen implants are also being investigated as part of a multi-pronged approach to tackle this problem. Some opportunities exist to limit scarring post-operatively, but it is an ongoing battle.

Angiogenesis in glaucoma filtration surgery and neovascular glaucoma: A review

Angiogenesis may pose a clinical challenge in glaucoma, for example, during the wound healing phase after glaucoma filtration surgery and in the severe secondary glaucoma called neovascular glaucoma (NVG). Upregulation of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis, occurs in eyes that have undergone glaucoma filtration surgery, as well as those with NVG. This has led investigation of the ability of anti-vascular endothelial growth factor therapy to improve outcomes, and we examine the findings with respect to the safety and efficacy of anti-vascular endothelial growth factor agents, mainly bevacizumab and ranibizumab, in eyes that have undergone glaucoma filtration surgery or have NVG. Combining conventional therapies-such as antimetabolites after filtration surgery and panretinal photocoagulation in NVG-and anti-vascular endothelial growth factor drugs may produce a synergetic effect, although further studies are required to evaluate the long-term efficacy of combination treatments.

Wound Healing Modulation in Glaucoma Filtration Surgery- Conventional Practices and New Perspectives: Antivascular Endothelial Growth Factor and Novel Agents (Part II)

Glaucoma filtration surgery is regularly performed for the treatment of glaucoma and trabeculectomy is often regarded as the ‘gold standard' glaucoma operation. The biggest risk of failure of the operation is bleb scarring. The advent of antifibrotic agents, such as mitomycin C (MMC) and 5-fluorouracil (5FU) has vastly prolonged the longevity of the bleb, but concerns remain regarding the potential increase in postoperative complications. More selective therapeutic targets have therefore been explored. One of these is vascular endothelial growth factor (VEGF) inhibition. VEGF inhibition has a role not only in subconjunctival angiogenesis inhibition but also it has direct anti-fibrotic properties. Newer pharmacological compounds and materials have also been developed in recent years in attempt to modulate the wound healing in different ways after glaucoma surgery. These include physical barriers to scarring and vehicles for sustained release of pharmacological agents, and early promising results have been demonstrated. This two-part review will provide a discussion of the application of anti-fibrotic agents in glaucoma filtration surgery and evaluate the newer agents that have been developed.

How to cite this article: Fan Gaskin JC, Nguyen DQ, Ang GS, O'Connor J, Crowston JG. Wound Healing Modulation in Glau coma Filtration Surgery–Conventional Practices and New Pers pectives: Antivascular Endothelial Growth Factor and Novel Agents (Part II). J Curr Glaucoma Pract 2014;8(2):46-53.

Improving patient outcomes following glaucoma surgery: state of the art and future perspectives

Of all the treatments currently used to lower intraocular pressure in glaucoma patients, filtration surgery is known to be the most effective. However, in a significant percentage of cases, the constructed channel closes due to excessive scar formation, resulting in surgical failure. The process of postoperative wound healing is characterized by the coagulative and inflammatory phase, followed by the proliferative and repair phase, and finally the remodeling phase. Perioperative antimitotic agents, such as mitomycin C and 5-fluorouracil, are known to modulate the process of wound healing and to improve surgical outcome, but they carry a risk of vision-threatening complications. New alternative strategies to prevent filtration failure, such as inhibition of transforming growth factor-β, vascular endothelial growth factor, and placental growth factor, have shown promising results in the improvement of surgical success. However, it remains necessary to broaden the therapeutic approach by focusing on combined therapies and on extended drug delivery.

Anti-VEGF agents with or without antimetabolites in trabeculectomy for glaucoma: a meta-analysis

PURPOSE

We aimed to evaluate the intraoperative application of antimetabolites compared with anti-vascular endothelial growth factor (VEGF) agents with or without antimetabolites in trabeculectomy (Trab) for glaucoma.

METHODS

Relevant studies were selected through extensive search using PubMed, EMBASE, the Cochrane Library, and Web of Science databases in August 2013. The primary efficacy estimate was measured using weighted mean difference of the percentage of intraocular pressure reduction (IOPR%) from baseline to end-point, and the secondary efficacy estimates were odds ratio (OR) and 95% confidence interval (CI) for complete success rate and qualified success rate. ORs were also used to measure the tolerability estimate for adverse events. Meta-analyses of fixed or random effects models were conducted using RevMan software 5.2 to pool the results of the studies included. Heterogeneity was assessed using Chi(2) test and the I(2) measure.

RESULTS

Nine studies enrolling a total of 349 patients were included. The weighted mean difference of IOPR% from baseline was 7.23 (95% CI: 2.57-11.89) for antimetabolites vs. anti-VEGF agents and 3.96 (95% CI: -4.18-12.10) for antimetabolites vs. anti-VEGF agents plus antimetabolites. The pooled ORs comparing antimetabolites with anti-VEGF agents were 2.37 (95% CI: 0.78, 7.21) for the complete success rate and 1.93 (95% CI: 0.52, 7.16) for qualified success rate. The pooled ORs comparing antimetabolites with anti-VEGF agents plus antimetabolites were 1.43 (95% CI: 0.48, 4.29) for the complete success rate and 2.11 (95% CI: 0.12, 37.72) for qualified success rate. The rates of adverse events did not significantly differ between antimetabolites and anti-VEGF agents, with pooled ORs of 0.86 (0.28-2.69) for bleb leakage, 3.01 (0.45-20.10) for choroidal effusion, 0.96 (0.23-3.98) for flat anterior chamber, and 0.90 (0.12-6.60) for hypotony. Further, the rates of adverse events were similar between antimetabolites and anti-VEGF agents plus antimetabolites, with pooled ORs of 0.40 (0.08-2.00) and 8.00 (0.93-68.59) for bleb leakage and hypotony, respectively.

CONCLUSIONS

In comparison with anti-VEGF agents, antimetabolites were more effective in lowering IOP in Trab, while the intraoperative application of these two types of agents did not indicate statistically significant differences in the complete success rate, qualified success rate, or incidence of adverse events.

The Anti-VEGF Epidemic: What are the Implications for Glaucoma Services?

The early reports on intraocular bevacizumab injections talked about a transient predictable probably volume-related rise in intraocular pressure (IOP). As the usage of the drug increased across the globe, sustained IOP elevation was noted. This article provides an insightly into the causes of IOP spikes and its impact on glaucoma practice.

Bevacizumab in Glaucoma: Where do We Stand?

The use of antivascular endothelial growth factors such as bevacizumab and ranibizumab has brought about a revolution in management protocols of various ophthalmic disorders. A lot has been written about these agents, still lacunae exist in our understanding due to paucity of randomized control trials with large number of patients. This brief review attempts to throw light on the clinical applications of these molecules for glaucoma.

HOW TO CITE THIS ARTICLE

Khanna A. Bevacizumab in Glaucoma: Where do We Stand? J Current Glau Prac 2012;6(2):75-78.