The use of amniotic membrane in trabeculectomy for the treatment of primary open-angle glaucoma: a prospective study

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).

The developments in amniotic membrane transplantation in glaucoma and vitreoretinal procedures

The main reasons why Amniotic Membrane (AM) is transplanted in Ophthalmology are: to provide a substrate for cellular growth and to provide tectonic support or as a biological bandage and barrier that protects the wound to facilitate an environment for wound healing. The application of AM is well-documented in corneal disorders of various aetiologies [1], however, research within the field has highlighted how it can be used in conjunctival disorders and most recently, in glaucoma and vitreoretinal procedures. This review explores the preservation modalities of AM and summarises the current literature regarding AM transplantation in Glaucoma and Vitreoretinal conditions. AM transplantation in conjunction with trabeculectomy was reported to be used in two different surgical techniques. They differ in relation to the position of the implant: below the scleral flap or over the entire exposed sclera. The results of these studies suggest that AM transplant is a safe procedure that helps in the improvement of the intraocular pressure when associated with trabeculectomies. Moreover, it enhances trabeculectomies success rates when used along with mitomycin C [2]. The use of AM is also described for managing leaking blebs. It is mentioned to be a suitable alternative to conjunctival advancement. Regarding AM transplantation in glaucoma shunt or valve surgeries, the current literature is relatively limited. However, AM has been described as a good tectonic support for shunt procedures [3]. Successful results are described in the literature for surgical treatments using AM plug for vitreoretinal procedures. In particular macular hole closure and rhegmatogenous retinal detachment. In conclusion, AM transplant is a very promising and versatile adjutant therapy. However, further studies are also required for a better understanding and refinement of surgical techniques.

Ologen implant versus mitomycin C in combined trabeculectomy and phacoemulsification

Purpose:

To comparatively evaluate in Indian eyes with coexisting cataract and primary open-angle glaucoma the outcome of mitomycin C (MMC) and Ologen implant as adjunctives in combined phacoemulsification with trabeculectomy.

Methods:

Eyes with primary open-angle glaucoma that underwent trabeculectomy and phacoemulsification with IOL implantation with either MMC application or Ologen implant between June 2019 and February 2020 were followed up for 12 months. Thirty-four eyes of 34 participants were studied. The primary outcome was intraocular pressure (IOP), and the secondary outcomes were the number of ocular hypotensives, best distance visual acuity (BDVA), and bleb morphology.

Results:

In 16 eyes treated with MMC and 18 eyes treated with Ologen implant, it was observed that the mean postoperative IOP (14.62 ± 2.89 mm Hg with MMC and 14.56 ± 4.14 mm Hg with Ologen implant) was not significantly different in both groups (P = 0.47). Number of ocular hypotensives and BDVA were also comparable between the two groups. However, bleb morphology was better with Ologen implantation. One eye in the MMC group developed hypotony which was conservatively managed

Conclusion:

MMC and Ologen are both effective adjunctives in combined phaco-trabeculectomy. However, the Ologen implant provides better bleb health and safety.

Use of Amniotic Membrane in MMC-Augmented Trabeculectomy: A Retrospective Comparative Study

Purpose

Amniotic membrane transplantation (AMT) has shown promising results as an antifibrotic agent in trabeculectomy. We aimed to evaluate the additional effect of AMT in MMC-augmented trabeculectomy.

Patients and Methods

This retrospective study analyzed the results of the first 12 postoperative months of glaucomatous eyes submitted to Moorfields Safer Surgery Trabeculectomy with MMC alone (non-AMT group) compared to MMC and AMT (AMT group). Both groups were compared in terms of intraocular pressure (IOP), number of antihypertensive medications and need for surgical reinterventions. Absolute and relative success rates 12 months after surgery were defined as IOP <18 mmHg, without and with the use of antihypertensive medications, respectively.

Results

The analysis included 51 eyes of 45 glaucoma patients (29 eyes in the non-AMT group and 22 in the AMT group). Mean IOP decreased from 24.72±5.11 mmHg and 26.86±10.62 mmHg preoperatively in non-AMT and AMT groups to 12.86±4.22 mmHg and 12.60±4.43 mmHg, respectively, at 12 months (p = 0.84). Postoperative number of medications decreased significantly in both groups. Absolute success was seen in 71% of non-AMT eyes and 55% of AMT eyes (p = 0.46), whereas relative success was obtained in 14% and 30%, respectively (p = 0.55). Reinterventions were needed in 28% of the eyes (11 bleb injection/needling and 4 Ahmed tube implantation) in the non-AMT group and in 27% of the AMT group (10 bleb injection/needling and 1 Ahmed tube implantation) (p = 0.89).

Conclusion

Trabeculectomy combined with MMC and AMT did not show better results than trabeculectomy with MMC alone.

Outcome of Trabeculectomy with Collagen Matrix Implant versus Mitomycin C in Primary Glaucoma: A Comparative Study

Background:

Glaucoma is a serious vision-threatening condition appropriately called as the silent killer of sight. The effect of postoperative fibrosis on success of filtration surgeries requires modulation of the wound healing process.

Aim:

The aim of the study was to compare trabeculectomy augmented with collagen matrix implant with mitomycin C in primary glaucoma.

Materials and Methods:

This prospective, longitudinal, hospital-based, analytical, and interventional study was conducted on 36 eyes of 36 patients. Group 1 included 18 patients who underwent trabeculectomy combined with subconjunctival collagen matrix implant and Group 2 included 18 patients who underwent trabeculectomy augmented with intraoperative mitomycin C (0.04 mg/ml) for 2 min. Each patient underwent detailed ocular examination and comparison was drawn by recording intraocular pressure (IOP), bleb characteristics, and postoperative complications.

Results:

The cumulative success rates at the end of our study were similar in two groups, 94.44% in Group 1 and 88.89% in Group 2 (P = 1.000). The mean reduction in IOP at 24 weeks in Group 1 was 18.67 ± 7.59 mmHg and in Group 2 was 21.32 ± 5.84 mmHg. The reduction in IOP was similar between the two groups (P = 0.290). The mean fall in IOP was 56.46% in Group 1 and 64.70% in Group 2 at 24 weeks. Mean bleb score in Group 1 was 10.33 ± 1.23 and in Group 2 was 8.89 ± 1.41, and the difference was statistically significant (P = 0.002). Shallow anterior chamber, overfiltration, and hypotony were statistically higher in Group 2 than in Group 1 (P = 0.041, 0.041, and 0.046, respectively).

Conclusion:

Collagen matrix implant as an adjuvant to trabeculectomy is noble, safe, and effective option as compared to mitomycin C.

Trabeculectomy with subconjunctival collagen implant in Indian eyes: Long-term results

Purpose

To report long-term safety and efficacy of trabeculectomy with collagen implant in Indian population.

Methods

All cases of trabeculectomy with Ologen^® Collagen Matrix implant performed over a 7-year period from May 2008 through April 2015 at a tertiary referral institute were reviewed. A total of 30 eyes of 28 patients were included in the study with two patients undergoing bilateral trabeculectomy. Outcomes measured included intraocular pressure (IOP) control, number of antiglaucoma medications used, bleb morphology, and complications/reoperations.

Results

Trabeculectomy resulted in reduction in IOP from 36.46 to 11.65 mm Hg in the immediate postoperative period (day 1), a 68% decrease to 15.18 mm Hg at 84 months (58% decrease). The mean IOP reduction decreased over time from 63% in the first year to 55% after 5 years of follow-up. Fourteen eyes attained a follow-up of 5 years and eight eyes a follow-up of ≥7 years. No sight-threatening complication such as hypotony, bleb leak, and bleb-related endophthalmitis was observed in our series, and only intervention required was 5-fluorouracil needling in one case.

Conclusion

Ologen-augmented trabeculectomy is effective in controlling IOP over a long-term follow up from minimal 3 to maximal 7 years. No untoward events jeopardizing bleb safety were noted at any time. This modality is a viable alternative for patients with contraindications to use of antimetabolites.

Simultaneous use of amniotic membrane and Mitomycin C in trabeculectomy for primary glaucoma

Purpose:

This study aimed to propose the role of amniotic membrane transplantation (AMT) as an additional modulator in primary Mitomycin C (MMC)-augmented trabeculectomy.

Methods:

This was a randomized prospective interventional study. Forty eyes of 39 adult patients with uncontrolled primary glaucoma were randomly divided into two equal groups. Control group underwent trabeculectomy augmented with MMC while the study group underwent additional AMT. Patients were followed up for 12 months and outcomes measured were intraocular pressure (IOP), need for additional intervention, and bleb morphology.

Results:

Complete success (defined as IOP <16 mmHg on no medication) could be achieved in 85% eyes in study group while it was 60% in control group (P = 0.04). IOP reduced by 71.1% in study group from 41.9 ± 10.6 to 12.1 ± 2.7 mmHg and from 40.5 ± 8.5 to 12.8 ± 4.5 mmHg in control group, a decline of 68.29%. Blebs in AMT group showed better bleb morphology in terms of significantly better extent (E3) on day 1 (P = 0.03) and better height (H2 and H3) (P = 0.04), according to the Indiana Bleb Appearance Grading Scale, at all follow-up visits along with normal vascularity. The study group required significantly lesser (P = 0.03) bleb needlings as compared to control group.

Conclusion:

Amnion enhanced the efficacy of MMC-modulated trabeculectomy in terms of eyes with complete success and lesser interventions such as bleb needling. This reiterates the role of amnion as a safe and effective bleb modulator. A diffusely elevated bleb with healthier conjunctiva can go a long way in predicting better health and longevity of the bleb.

Is device-modified trabeculectomy better than classic surgery for treatment of glaucoma?

Several techniques have emerged as complement or replacement for trabeculectomy, the standard surgery for glaucoma. Device-modified trabeculectomy is a recently developed technique whose results compared to the classical technique have not been fully defined. To answer this question, we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We identified eight systematic reviews including 34 studies overall. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. We concluded device-modified trabeculectomy probably leads to greater overall success rate and may decrease intraocular pressure more than classical surgery. In addition, this technique would probably have a better safety profile than standard trabeculectomy.

Trabeculectomy With Mitomycin-C Versus Trabeculectomy With Amniotic Membrane Transplant: A Medium-term Randomized, Controlled Trial

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering effect of trabeculectomy with the use of amniotic membrane transplant (AMT) compared with the standard trabeculectomy with Mitomycin-C (MMC) in patients with primary open-angle glaucoma.

PATIENTS AND METHODS

This study was a patient-masked, randomized, controlled comparison trial involving 52 eyes of 52 patients with bilateral primary open-angle glaucoma. Patients were randomized to receive trabeculectomy with AMT or trabeculectomy with MMC. The main outcome for comparison was the IOP-lowering effect of both procedures. Surgical success was considered if the patient's IOP was <22 mm Hg, and the IOPs were lowered by >20% without the use of any medication.

RESULTS

All surgeries passed uneventfully without intraoperative complications, and all patients showed significantly (P<0.05) lower IOP on the first postoperative day compared with their respective preoperative IOP with nonsignificant (P>0.05) difference between both study groups. All patients, irrespective of the operative procedure maintained significantly (P<0.05) lower IOP compared with their respective preoperative IOP till the end of 24 months follow-up. Moreover, patients of the AMT group showed lower IOP compared with those included in the MMC group throughout the follow-up period; however, the difference was not statistically significant at any point of the study period.

CONCLUSIONS

AMT exhibits potential as an alternative to MMC in trabeculectomy surgery. Over 24 months of follow-up, the use of AMT with trabeculectomy was safe and effective with an IOP-lowering effect comparable to that achieved with the use of MMC, and a reduced rate of postoperative complication.

Device-modified trabeculectomy for glaucoma

BACKGROUND

Glaucoma is an optic neuropathy that leads to vision loss and blindness. It is the second most common cause of irreversible blindness worldwide. The main treatment for glaucoma aims to reduce intraocular pressure (IOP) in order to slow or prevent further vision loss. IOP can be lowered with medications, and laser or incisional surgeries. Trabeculectomy is the most common incisional surgical procedure to treat glaucoma. Device-modified trabeculectomy is intended to improve drainage of the aqueous humor to lower IOP. Trabeculectomy-modifying devices include Ex-PRESS, Ologen, amniotic membrane, expanded polytetrafluoroethylene (E-PTFE) membrane, Gelfilm and others. However, the effectiveness and safety of these devices are uncertain.

OBJECTIVES

To assess the relative effectiveness, primarily with respect to IOP control and safety, of the use of different devices as adjuncts to trabeculectomy compared with standard trabeculectomy in eyes with glaucoma.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2014, Issue 12), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to December 2014), EMBASE (January 1980 to December 2014), PubMed (1948 to December 2014), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to December 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), 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 search for trials. We last searched the electronic databases on 22 December 2014.

SELECTION CRITERIA

We included randomized controlled trials comparing devices used during trabeculectomy with trabeculectomy alone. We also included studies where antimetabolites were used in either or both treatment groups.

DATA COLLECTION AND ANALYSIS

We used standard procedures expected by Cochrane.

MAIN RESULTS

We found 33 studies that met our inclusion criteria, of which 30 were published as full-length journal articles and three as conference abstracts. Only five studies have been registered. The 33 studies included a total of 1542 participants with glaucoma, and compared five types of devices implanted during trabeculectomy versus trabeculectomy alone. Five studies reported the use of Ex-PRESS (386 participants), eight studies reported the use of Ologen (327 participants), 18 studies reported the use of amniotic membrane (726 participants), one study reported the use of E-PTFE (60 participants), and one study reported the use of Gelfilm (43 participants). These studies were conducted in North America, South America, Europe, Asia, and the Middle East. Planned participant follow-up periods ranged from three months to five years. The studies were reported poorly which limited our ability to judge risk of bias for many domains. Only two studies explicitly masked outcome assessment so, we rated 31 studies at high risk of detection bias.Low-quality evidence from three studies showed that use of Ex-PRESS compared with trabeculectomy alone may be associated with a slightly lower IOP at one year (mean difference (MD) -1.58 mm Hg, 95% confidence interval (CI) -2.74 to -0.42; 165 eyes). Cataract surgery and hyphema may be less frequent in the Ex-PRESS group than in the trabeculectomy-alone group (cataract surgery: risk ratio (RR) 0.32, 95% CI 0.14 to 0.74, 3 studies, low-quality evidence; hyphema: RR 0.33, 95% CI 0.12 to 0.94, 4 studies, low-quality evidence). The effect of whether Ex-PRESS prevents hypotony was uncertain (RR 0.92, 95% CI 0.63 to 1.33, 2 studies, very low-quality evidence). All these studies received funding from the device manufacturer.Very low-quality evidence from five studies suggests that use of Ologen compared with trabeculectomy alone is associated with slightly higher IOP at one year (MD 1.40 mm Hg, 95% CI -0.57 to 3.38; 177 eyes). The effect of Ologen on preventing hypotony was uncertain (RR 0.75, 95% CI 0.47 to 1.19, 5 studies, very low-quality evidence). Differences between the two treatment groups for other reported complications also were inconclusive.Low-quality evidence from nine studies suggests that use of amniotic membrane with trabeculectomy may be associated with lower IOP at one year compared with trabeculectomy alone (MD -3.92 mm Hg, 95% CI -5.41 to -2.42; 356 eyes). Low-quality evidence showed that use of amniotic membrane may prevent adverse events and complications, such as hypotony (RR 0.40, 95% CI 0.17 to 0.94, 5 studies, low-quality evidence).The report from the only E-PTFE study (60 eyes) showed no important differences for postoperative IOP at one year (MD -0.44 mm Hg, 95% CI -1.76 to 0.88) between the trabeculectomy + E-PTFE versus the trabeculectomy-alone groups. Hypotony was the only postoperative complication observed less frequently in the E-PTFE group compared to the trabeculectomy-alone group (RR 0.29, 95% CI 0.11 to 0.77).The one Gelfilm study reported uncertainty in the difference in IOP and complication rates between the two groups at one year; no further data were provided in the study report.

AUTHORS' CONCLUSIONS

Overall, the use of devices with standard trabeculectomy may help with greater IOP reduction at one-year follow-up than trabeculectomy alone; however, due to potential biases and imprecision in effect estimates, the quality of evidence is low. When we examined outcomes within subgroups based on the type of device used, our findings suggested that the use of an Ex-PRESS device or an amniotic membrane as an adjunct to trabeculectomy may be slightly more effective in reducing IOP at one year after surgery compared with trabeculectomy alone. The evidence that these devices are as safe as trabeculectomy alone is unclear. 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 and 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).

Clinical outcomes of amniotic membrane loaded with 5-FU PLGA nanoparticles in experimental trabeculectomy

AIM

To evaluate the effect of amniotic membrane loaded with 5-fluorouracil poly (lactic-co-glycolic acid) (PLGA) nanoparticles (5-FU-NPs) in the surgical outcomes of experimental trabeculectomy in rabbits.

METHODS

Thirty-two New Zealand white rabbits were randomly categorized into four groups with 8 rabbits in each group. Group 1, the control group, performed traditional trabeculectomy without adjuvant treatment. While the experimental groups performed compound trabeculectomy with different implantations including amniotic membrane (group 2), 5-FU-NPs (group 3) and amniotic membrane loaded with 5-FU-NPs (group 4). Clinical evaluations including IOP measurement and filtration bleb analysis were performed in all groups postoperatively.

RESULTS

There is no significant difference of mean IOP in all groups at first 7d after surgery. While at P14, mean IOPs of experimental group 2 (9.8±2.1 mm Hg), groups 3 (8.9±2.8 mm Hg) and group 4 (7.6±2.3 mm Hg) were significantly reduced compared to control group (12.4±2.6 mm Hg; n=8, P<0.05). At P21, mean IOPs of groups 3 (11.7±3.2 mm Hg) and group 4 (9.9±1.6 mm Hg) were significantly decreased compare to control group (17.9±1.6 mm Hg) and group 2 (16.6±2.8 mm Hg; n=8, P<0.05). At P28, mean IOPs of groups 3 (13.8±3.3 mm Hg) and group 4 (10.6±2.0 mm Hg) were also significantly reduced compare to control group (19.4±2.3 mm Hg) and group 2 (18.5±2.4 mm Hg; n=8, P<0.05). Meanwhile mean IOP of group 4 is significantly decreased compared to group 3 at P28 (n=8, P<0.05). Survival analysis of functional filtration blub in all groups revealed the longest survival time in group 4 (24.9±5.1d) compared to that in group 3 (20.6±4.3d), group 2 (15.0±5.2d) and control group (10.1±5.7d).

CONCLUSION

Amniotic membrane loaded with 5-Fu-NPs may function as an effective anti-scarring implant and provides improved long-term surgical outcomes for experimental trabeculectomy in rabbits.

Amniotic membrane transplantation in failed trabeculectomy

PURPOSE

To determine the efficacy and safety of amniotic membrane transplantation for trabeculectomy in patients with previous failed filtering blebs.

METHODS

A consecutive series of 19 eyes from 18 patients with 1 or more failed trabeculectomies were enrolled in this retrospective study. Trabeculectomy, with amniotic membrane positioned as a "graft" under the scleral flap, was performed, and the intraocular pressure (IOP), number of antiglaucoma medications, appearance of the filtering bleb, and intraoperative and postoperative complication data were retrospectively analyzed for a period of 24 months. Success was defined as IOP<21 mm Hg at the end of the follow-up period.

RESULTS

The median preoperative pressure was 29 mm Hg [interquartile range (IQR)=5 mm Hg], with an average of 2.8 glaucoma medications (range, 1 to 4). At 6 months postoperatively the median IOP was 18 mm Hg (IQR=1.75 mm Hg) with no further significant increases recorded, settling at 19 mm Hg (IQR=3.25 mm Hg) at the end of the 24-month follow-up. Success was achieved in all 19 cases (100%), and only 1 patient (5%) required postoperative antiglaucoma therapy to reach the target pressure. At 24 months after surgery, 18 of 19 (95%) amniotic membrane filtering blebs were functioning well without antiglaucoma therapy. No patients had severe intraoperative or postoperative complications.

CONCLUSIONS

Amniotic membrane transplantation in trabeculectomy seems to be a safe and useful procedure for improving the surgical outcome and maintaining low postoperative IOP in patients with a high risk of surgical failure.

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.

Comparison of trabeculectomy and trabeculectomy with amniotic membrane transplantation in the same patient with bilateral glaucoma

AIM

To observe effects of trabeculectomy with amniotic membrane transplantation (AMT) in controlling postoperative intraocular pressure (IOP) in patients with medically uncontrolled glaucoma.

METHODS

This study included adult patients with requiring bilateral glaucoma surgery. Each patient underwent trabeculectomy (Non-AMT group) in one eye and with AMT (AMT group) in the other eye according to randomized principle. Success was defined as intraocular pressure (IOP)<21mmHg without any anti-glaucoma medications at 24 months follow-up. The two groups were compared in terms of IOP, complications and success rate.

RESULTS

Thirty-four eyes of 17 patients were investigated in this study. There was no statistically signifcant difference in pre-operative IOP between the two groups. The mean IOP was lower in AMT group compared with Non-AMT group on follow up months 12, 18, and 24.Postoperative complications were more frequent in Non-AMT group (35.3%, 6/17) compared with AMT group (5.9%, 1/17). The success rate of surgery was 88.2% (15/17) in Non-AMT group and 100% (17/17) in AMT group.

CONCLUSION

Trabeculectomy with AMT is an effective procedure to reduce IOP and complications, thereby improving surgical success rates.