Low-dose 5-fluorouracil trabeculectomy as initial surgery in uncomplicated glaucoma: long-term followup

Wound modulation in glaucoma surgery: The role of anti-scarring agents

Filtration surgery is one of the most frequently performed surgeries in the management of glaucoma, and trabeculectomy is considered the gold standard surgical technique for the same. Though trabeculectomy has been reported to have an excellent initial success rate, about 30% of them fail in 3 years, and nearly 50% of them fail in 5 years. The most significant risk of failure still seems to be wound scarring, especially episcleral fibrosis, leading to bleb failure. As a result, it is essential to explore the role of anti-scarring agents, including mitomycin C, and 5-fluorouracil in wound modulation and improving the bleb survival rate. Since these agents are widely used in trabeculectomy, it is crucial to understand the various modes of application, advantages, and adverse effects of these agents. On an evidence-based approach, all these points have been highlighted in this review article. In addition, the newer agents available for wound modulation and their scope for practical application are discussed.

Effect of vincristine on intraocular pressure and tear fluid oxidative stress biomarkers in canine transmissible venereal tumor

BACKGROUND

The ocular side effects of cancer chemotherapeutic drugs are relatively uncommon. Nonetheless, the ocular system has a potentially high sensitivity to toxic substances. This study proposed a framework to assess the effect of vincristine chemotherapy on intraocular pressure, tear protein, and oxidative stress in canines with transmissible venereal tumor (TVT).

METHODS

The study group comprised 10 dogs with TVT, whose diagnosis was based on cytology, and all dogs were treated with vincristine for 4 weeks. Each animal was given a complete ophthalmic examination, followed by a standard Schirmer tear test. Before and 20 min after administering vincristine, intraocular pressure (IOP) was measured in the eyes with a noncontact tonometer. At any of the times mentioned, tear samples were collected using the Schirmer test procedure and were subjected to protein analysis-oxidative stress index (OSI), total antioxidant capacity (TAC), total oxidant status (TOS), nitric oxide (NO), and malondialdehyde (MDA) were determined, and standard statistical analysis was applied.

RESULTS

No significant differences were found in protein in tears, but mean Pre and Postinjection IOP revealed a significant decrease in the eyes each week. Also, results indicated significant differences in oxidative stress markers: increased OSI, NO, and MDA, and reduced TAC.

CONCLUSION

The importance of an increase in oxidative stress levels in the tears of vincristine-treated patients should be taken seriously, as it appears to play a role in the pathogenesis of eye disease. Therefore, during the treatment weeks prior to prescribing vincristine, eye diseases should be evaluated and considered.

Long-Term Safety and Outcomes of β-radiation for Trabeculectomy

PRCIS

β-radiation is a neglected antiscarring therapy with past concerns for safety. This report found it safe and efficacious when used as an adjuvant to trabeculectomy surgery in 101 people (135 eyes) over 20 years.

PURPOSE

β-radiation has been used as an adjunct to prevent scarring in trabeculectomy surgery for many decades. Safety concerns were raised with the use of high doses on the bare sclera. Moorfields Eye Hospital has a large cohort of patients who have received β-radiation therapy. We report a review of the long-term safety and efficacy.

METHODS

Cases undertaken between August 1992 and August 1996 were reviewed. Those with records available for postoperative review of more than 5 years were included. Failure (reintervention/>21 mm Hg on 2 successive occasions) and any complication previously reported in association with β-radiation were the primary outcomes.

RESULTS

In total, 292 operations using β-radiation were recorded and 101 people (135 eyes) with trabeculectomy surgery and postoperative follow-up for over 4.5 years were included. The median follow-up period was 22.5 years. At the final follow-up, 48 (48%) single eyes per person had failed and 20/51 (51%) eyes with primary open angle glaucoma had cataract surgery. Other complications were rare and associated with copathology.

CONCLUSION

In glaucoma patients at risk of scarring and failure after trabeculectomy, as an antiscarring adjuvant, a 750 cGY dose of β-radiation was found to be safe and efficacious in the long term.

Long-term success after trabeculectomy in open-angle glaucoma: results of a retrospective cohort study

OBJECTIVE

To evaluate the long-term outcomes of trabeculectomy (TE) surgery in a large cohort with a minimum follow-up of 3 years.

DESIGN

Retrospective cohort study.

SETTING

University Eye Hospital, Germany.

PARTICIPANTS

Three hundred and seventy-nine patients with open-angle glaucoma underwent TE with mitomycin C (MMC) between January 2013 and February 2017 with a minimal follow-up of 3 years. Eligible patients were identified via an electronic surgical case register.

INTERVENTIONS

All patients had undergone TE with MMC following a set surgical protocol. To assess the influence of cataract surgery following TE, eyes which underwent cataract surgery at least 6 months after TE were matched 1:3 by sex and age to eyes who did not undergo cataract surgery during the follow-up period.

MAIN OUTCOME MEASURES

Primary outcome was the proportion of surgical success based on intraocular pressure (IOP), surgical complications, the need for revision surgery, loss of light perception and the need for additional pressure-lowering medication.

RESULTS

The mean follow-up time was 6 (±0.8, IQR: 5.4-6.5) years. Seventy-three per cent of eyes achieved qualified surgical success at the last follow-up (IOP≥5 mm Hg and ≤18 mm Hg, without surgical complications or complete loss of vision) but necessitated additional medical therapy, complete surgical success with no additional medical therapy was achieved in 69% of eyes. There was no significant difference in the success probability between eyes that had undergone cataract surgery after TE and those that had not (p=0.45).

CONCLUSIONS

The results demonstrate a high and stable success rate of TE after a mean follow-up time of approximately 6 years, that is, not affected by later cataract surgery.

The clinical and pathogenic spectrum of surgically-induced scleral necrosis: A review

The onset of scleral necrosis after ocular surgery may have catastrophic ocular and systemic consequences. The two most frequent surgeries causing surgically-induced scleral necrosis (SISN) are pterygium excision and cataract extraction. Several pathogenic mechanisms are involved in surgically induced scleral necrosis. All of them are poorly understood. Ocular trauma increasing lytic action of collagenases with subsequent collagen degradation, vascular disruption leading to local ischemia, and immune complex deposition activating the complement system represents some of the events that lead to scleral necrosis. The complex cascade of events involving different pathogenic mechanisms and the patient's abnormal immune response frequently leads to delayed wound healing that predisposes the development of scleral necrosis. The management of SISN ranges from short-term systemic anti-inflammatory drugs to aggressive immunosuppressive therapy and surgical repair. Therefore, before performing any ocular surgery involving the sclera, a thorough ophthalmic and systemic evaluation must be done to identify high-risk patients that may develop SISN.

Trabeculectomy in patients with diabetes: subconjunctival Mitomycin C with or without intravitreal bevacizumab

BACKGROUND/AIMS

To evaluate the success of Mitomycin C (MMC) augmented trabeculectomy with or without intravitreal bevacizumab in patients with diabetes without neovascular glaucoma.

METHODS

Fifty-six patients with diabetes who needed trabeculectomy were randomised to either combination of 2.5 mg intravitreal bevacizumab and subconjunctival MMC (group A, 28 eyes) or subconjunctival MMC alone (group B, 28 eyes). The main outcome measures were intraocular pressure (IOP), number of antiglaucoma medications, bleb morphology and success probability. Surgical success was defined as complete according to two levels of IOP (≤18 and <15 mm Hg) and at least 20% reduction from preoperative IOP without antiglaucoma medications and qualified as complete success but with antiglaucoma medications. Total success was the sum of complete and qualified success.

RESULTS

The mean age was 65.2±12.9 and 67.4±10.2 years in groups A and B, respectively (p=0.50). All patients completed at least 1 year of follow-up. The mean 1-year IOP decreased from 25.2±12.0 mm Hg to 10.1±2.8 in group A and from 26.4±11.6 mm Hg to 15.2±6.9 in group B (all p<0.001). Overall, postoperative IOP measurement was statistically significantly lower in group A at month 12 (p=0.001). The number of medications in groups A and B at month 12 was 0.3±0.8 and 1.0±1.2, respectively (p=0.02). The cumulative probability of success at month 12 was not statistically significant (89.3% group A, 78.6% group B; p=0.27).

CONCLUSION

In patients with diabetes with primary trabeculectomy, combined administration of intravitreal bevacizumab and subconjunctival MMC resulted in lower IOP and number of antiglaucoma medication compared with subconjunctival MMC alone.

Outcome and Complications of Combined Modified Deep Sclerectomy and Trabeculectomy for Surgical Management of Glaucoma: A Pilot Study

Purpose

To report the outcome and complications of a combined surgical technique of modified deep sclerectomy and trabeculectomy (mDST) for glaucoma.

Patients and Methods

Retrospective study of 44 eyes of 43 patients with open and closed angle glaucoma who underwent mDST. Outcome measures were: Surgical Success with 3 criteria - (i) criterion 1 = intraocular pressure (IOP) ≤21 mmHg or reduced by ≥20% of pre-operative IOP or IOP ≥6 mmHg on 2 consecutive time points after 3 months; (ii) criterion 2 = IOP ≤18 mmHg or reduced by ≥30% of pre-operative IOP or IOP ≥6 mmHg on 2 consecutive time points after 3 months and (iii) criterion 3 = IOP ≤15 mmHg or reduced by ≥40% of pre-operative IOP or IOP ≥6 mmHg on 2 consecutive time points after 3 months; IOP Reduction; Use of Anti-glaucoma Medication; Complications; Visual Acuity and Postoperative Interventions.

Results

Median follow-up was 40 months (range 24–77 months). At the final follow-up visit, the mean postoperative IOP was 11.5 ± 4.7 mmHg (p<0.0001). Mean number of anti-glaucoma medications decreased from 2.45 ± 1.21 to 0.54 ± 0.95 (p<0.0001). Surgical success in terms of IOP reduction was 50%; 43.2%; 36.4% for the 3 criteria respectively (complete success) and 70.5%; 56.8%; 47.7% for the 3 criteria respectively (qualified success). The complications noted were shallow/flat anterior chamber in 2 (4.54%), hyphema & bleb leak in 3 (6.81%), aqueous misdirection in 1 (2.27%), hypotonic maculopathy in 2 (4.45%) and hypotony requiring intervention in 6 (13.63%) eyes.

Conclusion

Combined mDST was found to be an effective surgical procedure in reducing IOP. It was associated with complications commonly encountered in glaucoma filtering surgery. The use of intra-scleral space maintainer may help lower the risk of flat or shallow anterior chamber during the early postoperative period.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/a82NJoWmPLg

The EX-PRESS glaucoma shunt versus nonpenetrating deep sclerectomy with Esnoper implant in combined surgery for open-angle glaucoma: a prospective randomized study

PURPOSE

To report 1-year treatment outcomes of P50 EX-PRESS implant versus nonpenetrating deep sclerectomy (NPDS) with Esnoper V2000 combined with phacoemulsification.

DESIGN

Randomized, prospective and multicentre clinical trial.

METHODS

Settings: Six clinical centres.

POPULATION

Patients 54-89 years of age without previous filtering surgery with cataract and glaucoma who required lower levels of intraocular pressure (IOP).

INTERVENTIONS

Phaco-EX-PRESS P50 or Phaco-NPDS with Esnoper V2000, both groups with mitomycin C (0.2 mg/ml for 2 min).

MAIN OUTCOME MEASURES

IOP, complete success rate (IOP: ≥6 and ≤18 mmHg), visual acuity, use of medical therapy and systematic assessment of complications and postoperative interventions.

RESULTS

A total of 98 eyes were enrolled, including 50 in the EX-PRESS group and 48 in the NPDS group. At 12 months, IOP (mean ± SD) was 13.9 ± 3.3 mmHg in EX-PRESS group and 13.3 ± 3.6 mmHg in NPDS group (p = 0.38). Success rate was 75% and 80% in EX-PRESS and NPDS groups, respectively (p = 0.53). The number of glaucoma medications (mean ± SD) was 0.2 ± 0.55 in EX-PRESS group and 0.17 ± 0.44 in NPDS group (p = 1.00). The total number of complications was 66 in 35 subjects in EX-PRESS group and 39 in 23 subjects in NPDS group (p = 0.02). The incidence of more than one complication was n = 13 (26%) versus n = 9 (18.8%) in EX-PRESS and NPDS groups, respectively (p = 0.38). The total number of required postoperative interventions was 59 and 26 in EX-PRESS and NPDS groups, respectively (p = 0.01). Visual acuity was similar in both groups at month 12 (p = 0.13). Surgical time (mean ± SD) was 52.6 ± 13.6 min in EX-PRESS group and 63.3 ± 19.4 min in NPDS group (p = 0.01).

CONCLUSION

Phaco-EX-PRESS surgery had similar success rate compared to Phaco-NPDS during 1 year of follow-up. Both procedures were associated with similar IOP reduction and use of additional medical therapy at 12 months. EX-PRESS surgery required more postoperative interventions and had more complications, but needed less surgical time compared to NPDS.

Evaluating the efficacy of short duration Mitomycin C in safe surgery system trabeculectomy combined with cataract surgery

Purpose: To compare the efficacy of 0.2 mg/ml Mitomycin C (MMC) applied for 1-minute versus 2-minutes in patients undergoing combined surgery for primary glaucoma coexistent with cataract. Materials and methods: This was a randomized controlled clinical trial of 63 patients operated on for primary glaucoma (POAG or PACG) with visually significant cataract. All patients underwent safe surgery system trabeculectomy with manual small incision cataract surgery (MSIC) and implantation of PC IOL. Patients were randomized into intra-operative MMC 0.2 mg/ml for 1-minute (study group) and MMC 0.2 mg/ml for 2-minutes (control group). Success was measured on the basis of two different intraocular pressure (IOP) goals (IOP ≤21 mmHg, IOP ≤18 mmHg) and mean IOP reduction from baseline at the end of 12 months. Results: At 12 months, significant decreases in mean IOP were observed in both groups (P<0.001).The mean IOP reduction was 31.33±9.06% in the study group, as compared to 43.32±9.38% in the control group (P<0.001). The overall success for IOP ≤21 mm Hg was 80.5% in the study group and 90.9% in the control group (P<0.05). Kaplan-Meier analysis showed an insignificant difference in overall success rates of the two groups. Conclusion: The IOP reduction with 2-minute MMC (0.2 mg/ml) is more effective than 1-minute MMC after 12 months. It offers a decrease in anti-glaucoma medications and substantial visual recovery in combined surgery done for primary glaucoma coexistent with cataract.

[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.

Bleb-related infections and long-term follow-up after trabeculectomy

PURPOSE

Bleb-related infections are serious complications after trabeculectomy. They can be limited to the bleb or disseminate and lead to endophthalmitis. We herein report on all bleb-related infections that have been diagnosed at the Eye Center of the University of Freiburg, Germany, since 1999.

METHODS

We reviewed a total of 1816 consecutive trabeculectomies that were performed at our hospital between the years 1999 and 2014 (353 without and 1463 with intraoperative application of mitomycin C). All bleb-related infections that were diagnosed at our clinic during the same period were included in the analysis. We fitted a Cox proportional hazards model to characterize risk factors for bleb-related infections.

RESULTS

We diagnosed a total of 19 bleb-related infections in this period. Three patients with bleb-related infections that came to our clinic had their trabeculectomy performed elsewhere. The overall percentage of bleb-related infections was 0.1% after 2 years (Kaplan-Meier estimate at median follow-up). Nine eyes suffered from only localized infection of the bleb. Seven eyes developed endophthalmitis. Four infections occurred during the first postoperative month. The median age on the day of diagnosis was 71 years; the median age at surgery was 69 years. In the Cox model, intraoperative application of mitomycin C and a fornix-based conjunctival flap were identified as significant risk factors (hazard ratio: 79.02, 4.69; p < 0.01, p < 0.01). The whole group showed a reduction of visual acuity in the median from logMAR 0.12 to 0.2. Eyes that suffered from endophthalmitis showed a loss from 0.3 to 0.96, while the localized infections had a reduction from 0.04 to 0.07.

CONCLUSION

Bleb-related infections are a rare complication following trabeculectomy and can be localized on the bleb or can lead to endophthalmitis, thereby threatening visual acuity. The risks and benefits of mitomycin C-augmented trabeculectomies should be taken into consideration.

Trabeculectomy bleb needling and antimetabolite administration practices in the UK: a glaucoma specialist national survey

AIMS

To evaluate, describe and quantify the diversity in postoperative antimetabolite administration and bleb needling practices among glaucoma specialists performing trabeculectomy surgery within the UK and Ireland.

METHODS

A cross-sectional online survey was distributed to all consultant glaucoma specialists who are on the United Kingdom and Eire Glaucoma Society (UKEGS) contact list. Participants were asked specific questions about their current practices for post-trabeculectomy antimetabolite administration followed by questions directly related to bleb needling procedures.

RESULTS

60 (83%) of UKEGS glaucoma subspecialty consultants completed the survey. 70% of respondents administered 5-fluorouracil (5-FU) in their clinic room while 30% used a separate treatment room. Doses of 5-FU varied considerably but 70% used 5 mg as standard. Techniques used to reduce corneal toxicity included precipitation with amethocaine (44%) or benoxinate (14%), saline wash (14%) and modified injection technique (8%). Topical antibiotics and/or betadine were used to prevent infection following 5-FU injection in just over 50%. Bleb needling was exclusively performed in operating theatre by 56% of respondents and solely at the slit lamp in the clinic room by 12%. A further 30% used a combination of both theatre and outpatient clinic rooms. Anti-metabolites used were 5-FU (72%) and mitomycin C (22%) with 12% using either of the two substances.

CONCLUSIONS

There is a significantly wide variety of current practices for antimetabolite administration and bleb needling within the UK and Ireland. This may be influenced by a glaucoma surgeon's specific experience and audit results as well as particular clinical set-up, availability of antimetabolite and clinic room space.

The CLC-2 Chloride Channel Modulates ECM Synthesis, Differentiation, and Migration of Human Conjunctival Fibroblasts via the PI3K/Akt Signaling Pathway

Recent evidence suggests that chloride channels are critical for cell proliferation, migration, and differentiation. We examined the effects of transforming growth factor (TGF)-β1 on chloride channel expression and associations with human conjunctival fibroblast (HConF) biology. To investigate the potential role of chloride channel (CLC)-2 in migration, transition to myofibroblasts and extracellular matrix (ECM) synthesis of HconF, a small interfering RNA (siRNA) approach was applied. TGF-β1-induced migration and transition of fibroblasts to myofibroblasts characterized by α-smooth muscle actin (α-SMA) expression, supported by increased endogenous expression of CLC-2 protein and mRNA transcripts. ECM (collagen I and fibronectin) synthesis in HConF was enhanced by TGF-β1. CLC-2 siRNA treatment reduced TGF-β1-induced cell migration, transition of fibroblasts to myofibroblasts, and ECM synthesis of HConF. CLC-2 siRNA treatment in the presence of TGF-β1 inhibited phosphorylation of PI3K and Akt in HConF. These findings demonstrate that CLC-2 chloride channels are important for TGF-β1-induced migration, differentiation, and ECM synthesis via PI3K/Akt signaling in HConF.

Current and Future Techniques in Wound Healing Modulation after Glaucoma Filtering Surgeries

Filtering surgeries are frequently used for controlling intraocular pressure in glaucoma patients. The long-term success of operation is intimately influenced by the process of wound healing at the site of surgery. Indeed, if has not been anticipated and managed accordingly, filtering surgery in high-risk patients could end up in bleb failure. Several strategies have been developed so far to overcome excessive scarring after filtering surgery. The principal step involves meticulous tissue handling and modification of surgical technique, which can minimize the severity of wound healing response at the first place. However, this is usually insufficient, especially in those with high-risk criteria. Thus, several adjuvants have been tried to stifle the exuberant scarring after filtration surgery. Conventionally, corticosteroids and anti-fibrotic agents (including 5-fluorouracil and Mitomycin-C) have been used for over three decades with semi-acceptable outcomes. Blebs and bleb associated complications are catastrophic side effects of anti-fibrotic agents, which occasionally are encountered in a subset of patients. Therefore, research continues to find a safer, yet effective adjuvant for filtering surgery. Recent efforts have primarily focused on selective inhibition of growth factors that promote scarring during wound healing process. Currently, only anti-VEGF agents have gained widespread acceptance to be translated into routine clinical practice. Robust evidence for other agents is still lacking and future confirmative studies are warranted. In this review, we explain the importance of wound healing process during filtering surgery, and describe the conventional as well as potential future adjuvants for filtration surgeries.

Wound Healing Modulation in Glaucoma Filtration Surgery-Conventional Practices and New Perspectives: The Role of Antifibrotic Agents (Part I)

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 anti-fibrotic 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. Vascular endothelial growth factor inhi bition has a role not only in sub conjunctival angiogenesis inhi bition but also it has direct anti-fibrotic properties. Newer phar macological 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 Glaucoma Filtration Surgery–Conventional Practices and New Pers pectives: The Role of Antifibrotic Agents (Part I). J Curr Glaucoma Pract 2014;8(2):37-45.

Trabeculectomy in the 21st century: a multicenter analysis

OBJECTIVE

To evaluate the efficacy and safety of current trabeculectomy surgery in the United Kingdom.

DESIGN

Cross-sectional, multicenter, retrospective follow-up.

PARTICIPANTS

A total of 428 eyes of 395 patients.

METHODS

Consecutive trabeculectomy cases with open-angle glaucoma and no previous incisional glaucoma surgery from 9 glaucoma units were evaluated retrospectively. Follow-up was a minimum of 2 years.

MAIN OUTCOME MEASURES

Surgical success, intraocular pressure (IOP), visual acuity, complications, and interventions. Success was stratified according to IOP, use of hypotensive medications, bleb needling, and resuturing/revision for hypotony. Reoperation for glaucoma and loss of perception of light were classified as failures.

RESULTS

Antifibrotics were used in 400 cases (93%): mitomycin C (MMC) in 271 (63%), 5-fluorouracil (5-FU) in 129 (30%), and no antifibrotic in 28 (7%). At 2 years, IOP (mean ± standard deviation) was 12.4 ± 4 mmHg, and 342 patients (80%) achieved an IOP ≤ 21 mmHg and 20% reduction of preoperative IOP without IOP-lowering medication, whereas 374 patients (87%) achieved an IOP ≤ 21 mmHg and 20% reduction of preoperative IOP overall. An IOP ≤18 mmHg and 20% reduction of preoperative IOP were achieved by 337 trabeculectomies (78%) without IOP-lowering treatment and by 367 trabeculectomies (86%) including hypotensive medication. Postoperative treatments included suture manipulation in 184 patients (43%), resuturing or revision for hypotony in 30 patients (7%), bleb needling in 71 patients (17%), and cataract extraction in 111 of 363 patients (31%). Subconjunctival 5-FU injection was performed postoperatively in 119 patients (28%). Visual loss of >2 Snellen lines occurred in 24 of 428 patients (5.6%). A total of 31 of the 428 patients (7.2%) had late-onset hypotony (IOP <6 mmHg after 6 months). In 3 of these, visual acuity decreased by >2 Snellen lines. Bleb leaks were observed in 59 cases (14%), 56 (95%) of which occurred within 3 months. Two patients developed blebitis. Bleb-related endophthalmitis developed in 1 patient within 1 month postoperatively and in 1 patient at 3 years. There was an endophthalmitis associated with subsequent cataract surgery.

CONCLUSIONS

This survey shows that good trabeculectomy outcomes with low rates of surgical complications can be achieved, but intensive proactive postoperative care is required.

Current variations of glaucoma filtration surgery

PURPOSE OF REVIEW

Trabeculectomy continues to be the most effective incisional surgery for uncontrolled glaucoma. Since its introduction by Cairns in 1968, the procedure has undergone numerous modifications. This article will summarize the current variations of glaucoma filtration surgery and evidence-based review of their potential advantages and disadvantages.

RECENT FINDINGS

Recent innovations in glaucoma filtration surgery have focused on wound modulation to enhance long-term surgical outcomes and the search for a small incision surgery with more predictable outcomes, lower complication rates, and rapid visual recovery. Amniotic membranes, antivascular endothelial growth factor agents, and tissue-engineered biodegradable implants are currently being investigated as alternatives to mitomycin C and 5-fluorouracil to reduce inflammation and subsequent bleb failure with fewer complications. The Ex-PRESS glaucoma filtration device appears promising with its unique feature of small-incision surgery, fewer intraoperative and postoperative complications, and its ability to lower intraocular pressure significantly, which appears to be comparable with standard trabeculectomy.

SUMMARY

Knowledge and surgical expertise in handling current variations of glaucoma filtration surgery are essential to offer an individualized approach with the overall goal of optimizing surgical outcomes and minimizing complications.

Efficacy and safety of a steel drainage device implanted under a scleral flap

OBJECTIVE

To evaluate the efficacy and safety of a stainless steel miniature glaucoma drainage device (Ex-PRESS X200) implanted under a scleral flap for the surgical treatment of primary open-angle glaucoma (POAG).

STUDY DESIGN

Clinical, prospective, noncomparative, nonrandomized study. The efficacy and safety were evaluated on the full sample, with a minimum follow-up of 12 months (maximum 24, mean 18).

PARTICIPANTS

Thirty-seven eyes of 35 patients.

METHODS

The Ex-PRESS device was implanted under a scleral flap in patients with POAG.

RESULTS

Preoperative intraocular pressure (IOP) was 27.6 (SD 8.7) mm Hg; at last follow-up, IOP was 12.4 (SD 3.4) mm Hg (55.1% reduction). The success rates (IOP < 18 mm Hg and < 15 mm Hg at last visit without medications) were 78.4% (29/37) and 70.3% (26/37), respectively. Kaplan-Meier analyses (probability of IOP < 18 mm Hg and < 15 mm Hg without medications) at last follow-up were 72.6% and 47.9%, respectively. Early postoperative complications were clinically mild and included postoperative IOP < 5 mm Hg: 12 cases at 1 day, 8 cases at 1 week, 3 cases at 1 month, 1 case at 3 months; serous choroidal detachment: 9 cases, of which 3 spontaneously resolved, whereas in 6 cases, hypotony and flat chamber were treated with viscoelastic injection in the anterior chamber. At last follow-up, 6 patients were treated with 2 IOP-lowering medications. No sight-threatening consequences of surgery were observed. There were 8 cases (21.6%, n = 37) of bleb needling.

CONCLUSIONS

Our data support the efficacy and safety of the implantation of this device under a scleral flap. The IOP reduction obtained was significant and long standing and complications were mild.

Magnetic resonance imaging in patients implanted with Ex-PRESS stainless steel glaucoma drainage microdevice

PURPOSE

To evaluate whether artifacts caused by a stainless steel glaucoma drainage device can alter the interpretation of magnetic resonance imaging (MRI) scans of the optic nerve and brain.

DESIGN

Consecutive case series.

METHODS

Five patients (7 eyes) with Ex-PRESS devices (Optonol Ltd, Neve Ilan, Israel) positioned at the limbus were studied. For each subject, an axial T1-weighted, axial and coronal T2-weighted with fat saturation, and whole brain proton density (PD)/T2-weighted MRI scan was obtained. Standard MRI protocol was not optimized for the imaging of patients harboring Ex-PRESS implants. The effects of the device on PD/T2 pulse sequence imaging of the optic nerve and brain were rated from 1 (optic nerve margins unidentifiable or brain details altered) to 5 (excellent visualization of the optic nerve and brain).

RESULTS

For optic nerve visualization, 1 optic nerve scored 2, 3 optic nerves scored 3, and 3 optic nerves scored 4 (mean, 3.3 +/- 0.8 standard deviation). For whole brain imaging, 4 patients scored 4 and 1 patient scored 5 (mean, 4.2 +/- 0.4 standard deviation).

CONCLUSIONS

Our data demonstrate that interpretation of MRI scans of the orbit and brain is unaffected by the artifacts caused by the Ex-PRESS shunt, whereas optic nerve imaging may be affected. We are unaware of previous reports of this finding and could find no reference to it in a computerized search using PubMed.

The Ex-PRESS glaucoma shunt versus trabeculectomy in open-angle glaucoma: a prospective randomized study

INTRODUCTION

The purpose of this study was to establish the efficacy and safety of the Ex-PRESS (Optonol Ltd., Neve Ilan, Israel) mini glaucoma shunt in open-angle glaucoma.

METHODS

This was a prospective, randomized trial. Eyes from enrolled patients were randomly assigned to either Ex-PRESS implantation under a scleral flap, or trabeculectomy. The main outcome measures were: mean intraocular pressure (IOP), postoperative medication use, visual acuity, and incidence of complications. Complete success was defined as an IOP of >4 mmHg and <or=18 mmHg without the use of antiglaucoma medications. A more stringent target of IOP >4 mmHg and <or=15 mmHg was also noted.

RESULTS

There were 78 patients (80 eyes) with primary open-angle, pseudoexfoliative, or pigmentary glaucoma enrolled in the study. A total of 84.6% of patients receiving Ex-PRESS and 60.0% of patients receiving trabeculectomy (P=0.0230) achieved complete success. The respective proportions of patients achieving an IOP >4 mmHg and <or=15 mmHg were 76.9% and 50.0% (P=0.0193). At 1-year follow-up, complete success rates were 81.8% for Ex-PRESS and 47.5% for trabeculectomy (P=0.0020), and 71.7% and 37.5% (P=0.0070), respectively, for the more stringent target. There was a similar level of postoperative interventions and complications for each group.

CONCLUSIONS

In open-angle glaucoma, the Ex-PRESS mini glaucoma shunt implanted under a superficial scleral flap produces significantly higher success rates, and a similar complication rate, compared with trabeculectomy. The Ex-PRESS is a safe and effective device for treating open-angle glaucoma.

Cost-effectiveness of latanoprost and timolol maleate for the treatment of glaucoma in Scandinavia and the United Kingdom, using a decision-analytic health economic model

PURPOSE

To assess the cost-effectiveness of latanoprost or timolol in glaucoma treatment in Norway, Sweden, Denmark (Scandinavia) and the United Kingdom (UK).

METHODS

A Markov model was constructed to perform a cost-effectiveness analysis. Health states were 'stable' and 'progressed' glaucoma, and transition probabilities for both primary open-angle and exfoliation glaucoma were derived from the medical literature. Practice patterns were obtained from surveys completed by 54 ophthalmologists geographically dispersed throughout each country. Country specific unit costs were used for medications, patient visits, diagnostics, and therapeutic procedures.

RESULTS

Over the life of the model latanoprost was less expensive than timolol by 5.3-7.6% (Scandinavia) and 2.1% (UK). Following adjustments, therapy in the original timolol-treated cohort was slightly more effective in each country with a difference in 0.003-0.015 years to progression of glaucoma existing between latanoprost. This may have resulted from the model design, which reflected that physicians ultimately control most patients' glaucoma over 5 years by adding or changing therapy. The associated incremental cost-effectiveness ratios for latanoprost vs timolol generated by the Scandinavian and the UK models, respectively, were: Norway 351,396 NOK; Sweden 988,985 SEK; Denmark 351,641; and the UK 4751 GBP.

CONCLUSIONS

Over 5 years, in the UK timolol is the cost-effective option, whereas in Scandinavia latanoprost may be the cost-effective alternative to timolol.

Non-penetrating glaucoma surgery augmented with mitomycin C or 5-fluorouracil in eyes at high risk of failure of filtration surgery: long-term results

PURPOSE

To investigate the long-term efficacy and safety of non-penetrating glaucoma surgery (NPGS) augmented with mitomycin C (MMC) or 5-fluorouracil (5FU) in eyes at high risk of failure of glaucoma filtration surgery.

METHODS

Prospective study of all eyes, undergoing NPGS with 0.04% MMC (1 to 2 min topical or 0.04 mL subconjunctival injection into the superior fornix) or 5FU (25 mg/mL topically for 5 min). Complete success was an intraocular pressure (IOP)<or=21 mmHg on no medication and qualified success an IOP<or=21 mmHg with topical medication. An additional criterion for success was a >or=20% drop in IOP or a reduction of at least two medications.

RESULTS

Twenty-three eyes of 22 patients with a mean follow up of 41.4 months were reviewed. Fifteen eyes had failed trabeculectomy and seven had uveitic glaucoma. Mean preoperative IOP reduced from 25.8+/-7.8 to 15.4+/-4.9 mmHg at final visit, a mean change of 41%. Median number of preoperative medications decreased from 3 to 0 postoperatively. Cumulative probability of success was 100% at 2 years, 94% at 3 years and 85% at 4 years. No patient developed any long-term complications. Complete success was achieved in 11 eyes and qualified success in 10 eyes. Two eyes failed and required further surgery.

CONCLUSION

NPGS augmented with small-volume MMC/5FU provides good long-term IOP control in eyes at high risk of failure with a lower incidence of complications compared with augmented trabeculectomy and eliminates the need for postoperative bleb or suture manipulation.

Randomized comparison of the intraocular pressure-lowering effect of phacoviscocanalostomy and phacotrabeculectomy

PURPOSE

To compare the intraocular pressure (IOP)-lowering effect of combined viscocanalostomy and phacoemulsification and combined trabeculectomy and phacoemulsification with mitomycin C in eyes with primary open-angle glaucoma.

DESIGN

Prospective randomized 1-year trial.

PARTICIPANTS

Forty consecutive patients (40 eyes) with primary open-angle glaucoma and cataract.

INTERVENTION

Eyes were assigned randomly either to trabeculectomy with mitomycin C or to viscocanalostomy in combination with phacoemulsification and intraocular lens implantation.

MAIN OUTCOME MEASURES

Success rate based on IOP.

RESULTS

Mean baseline IOP was 24.0+/-2.0 mmHg in the viscocanalostomy group and 23.7+/-2.6 mmHg in the trabeculectomy group (P = 0.7). Mean postoperative IOP was 13.7+/-2.2 mmHg at 3 months, 14.8+/-3.3 mmHg at 6 months, and 14.9+/-3.0 mmHg at 12 months in the viscocanalostomy group and 12.1+/-4.0 mmHg at 3 months, 13.8+/-4.7 mmHg at 6 months, and 14.1+/-4.4 mmHg at 12 months in the trabeculectomy group. There was no significant difference in the mean IOP between the groups at any time. At 12 months, 17 patients (85%) in the viscocanalostomy group and 16 patients (80%) in the trabeculectomy group achieved an IOP of 20 mmHg or less without medication (P = 0.7). Complications included 2 cases (10%) of flat/shallow anterior chamber and 4 cases (20%) of hypotony in the trabeculectomy group, whereas intraoperative microperforation of Descemet's membrane occurred in 3 cases (15%) in the viscocanalostomy group.

CONCLUSIONS

There was no significant difference in IOP reduction between viscocanalostomy and trabeculectomy with mitomycin C in combination with phacoemulsification and intraocular lens implantation in patients with primary open-angle glaucoma.

The Clinical Applications of Fluorouracil in Ophthalmic Practice

Fluorouracil (5-fluorouracil, 5-FU) is a pyrimidine analogue that was originally known for its widespread use as an anticancer drug. The ability of 5-FU to reduce fibroblastic proliferation and subsequent scarring has made it an important adjunct in ocular and periorbital surgeries. It is used in primary glaucoma filtering surgeries and in reviving failing filtering blebs, in dacryocystorhinostomy, pterygium surgery, and in vitreoretinal surgery to prevent proliferative vitreoretinopathy. In addition, 5-FU is also gaining recognition in the treatment and surgical management of ocular surface malignancies like ocular surface squamous neoplasia; however, the specific action of the drug on highly proliferating cells limits its use in primary acquired melanosis of the conjunctiva. When applied topically, this drug has a low rate of sight-threatening adverse effects, is inexpensive, and is easy to administer, making it an important tool in enhancing the success rate in ophthalmic surgery and in reducing the recurrence of ocular surface neoplasia.

Dose, timing and frequency of subconjunctival 5-fluorouracil injections after glaucoma filtering surgery

BACKGROUND

Although adjunctive postoperative 5-fluorouracil (5-FU) injections are known to improve the success rate of glaucoma surgery, it is still unknown what dose, timing and frequency of application will give the best results with respect to the inhibition of postoperative scarring and intraocular pressure regulation. We therefore designed the following retrospective investigation.

METHODS

We studied 172 eyes from 172 patients who had undergone trabeculectomy with adjuvant 5-FU-therapy. Variations of dosage, timing and frequency were analysed retrospectively. Surgery was defined as a complete success when the patient reached an intraocular pressure under 21 mmHg and a reduction of 20% 12 months after the operation. A relative success was achieved with these criteria under additional local medication. Not reaching these postoperative criteria for a complete success was classified as failure.

RESULTS

On average, adjunctive 5-FU-treatment was started 4.6+/-5.85 days postoperatively. The injections contained between 2 mg and 5 mg FU, and the mean total dose was 26.6+/-13.2 mg (range 5-65 mg). Surgery on 94 patients (54.65%) was classified as "complete success", that on 25 patients (14.53%) was classified as "relative success" and that on 53 eyes (30.81%) was classified as "failure" 12 months (+/-3 months) postoperatively. The best results were obtained when the treatment started on or before the first postoperative day (68.0-71.4% complete success; P<0.05). In contrast, an increase in 5-FU dosage did not result in an increased success rate of trabeculectomy. None of the 172 patients suffered from vision-threatening complications such as endophthalmitis or hypotony maculopathy.

CONCLUSION

Early treatment with 5-FU significantly increases the success rates of filtering surgery.

Do injections of 5-fluorouracil after trabeculectomy have toxic effects on the anterior segment?

OBJECTIVE

To discourage fibrosis of the filtering bleb, 5 fluorouracil (5-FU) may be injected after trabeculectomy. 5-FU is an antimetabolite that also can damage extraocular tissues at concentrations as low as 0.5%. This study ascertained whether repeated injection of 5-FU has toxic effects on intraocular structures.

METHODS

After unilateral trabeculectomy in anesthetized New Zealand rabbits, 5-FU (5.0 mg/0.1 mL) was injected at the trabeculectomy site every 5 days for 15 days. Evaluation included slit-lamp examination, confocal microscopy, and intraocular pressure (IOP). After sacrifice, aqueous humor (AH) was drawn and eyes excised for scanning electron microscopy (SEM) and light microscopy.

RESULTS

The 5-FU injection not decrease IOP beyond trabeculectomy alone. Bleb height remained constant, thickness increased, and vascularity decreased. No changes in cornea or anterior segment were observed. No inflammation was observed in the bleb or surrounding tissues by slit-lamp or histologic examination. Protein in AH increased from 0.6 +/- 0.5 microg/mL at baseline to 19.8 +/- 4.4 microg/mL after trabeculectomy but only to 0.9 +/- 0.6 microg/mL after trabeculectomy plus 5-FU. Both in vivo confocal microscopy and SEM revealed deleterious effects on corneal epithelial and endothelial cells with a minor shift toward smaller cells.

CONCLUSIONS

In this study 5-FU did not provoke an intraocular inflammatory response and had minimal effect on extraocular structures. Changes in corneal epithelium and endothelium detectable by confocal microscopy suggest a small toxic effect. These in vivo measurements by confocal microscopy were confirmed by SEM. Repeated administration did not cause additional cumulative toxic effects in the anterior segment. Therefore, multiple injections of 5- FU into the filtering bleb pose minimal risk to intraocular structures.

Long term effect on IOP of a stainless steel glaucoma drainage implant (Ex-PRESS) in combined surgery with phacoemulsification

AIM

To evaluate the efficacy and safety of a stainless steel miniature glaucoma drainage device (Ex-PRESS R50) for the surgical treatment of primary open angle glaucoma (POAG) and cataract when combined with phacoemulsification.

METHODS

Clinical, prospective, multicentre, single treatment arm, non-randomised, non-masked study. The Ex-PRESS device was implanted at the limbus under a conjunctival flap. Phacoemulsification cataract extraction and in the bag IOL implantation were performed through clear cornea temporally.

PRIMARY OUTCOME

IOP change; secondary outcomes: side effects and VA changes.

RESULTS

26 eyes of 25 patients were implanted with the device. The mean (SD) follow up was 23.9 (10.4) months and the mean age was 75.1 (7.1) years. 17/26 eyes have more than 3 years of follow up. One case was discontinued because of device removal, one because of death, and three were lost to follow up.

EFFICACY

preoperative IOP was 21 (4) mm Hg; at 1, 2, and 3 years IOP was 15.3 (3.1) mm Hg (35% reduction), 16.6 (2.7) mm Hg (29% reduction), and 16 (2.6) mm Hg (22% reduction) respectively. Kaplan-Meyer determined overall success rate (IOP < or = 21 mm Hg at the last visit with or without medications) as 76.9%. The number of antiglaucoma medications was reduced by 95% at year 1. Only six patients (23%) were taking IOP lowering treatment at their last visit, five with one medication and one with two medications. Side effects: early postoperative complications were clinically mild and included six cases of hypotony (IOP <5 mm Hg), three cases of hyphaema (<2 mm) with no clinically significant further effects. Long term complications were two cases (7.7%) of device rotation (one treated by reposition) and three cases (11.5%) of conjunctival erosion at 2 and 3 years.

CONCLUSIONS

The Ex-PRESS implant, combined with phacoemulsification cataract extraction, is clinically safe and effective, maintaining in the long term a large reduction in IOP and in the number of antiglaucoma medications.

Reducing intraocular pressure: is surgery better than drugs?

Reducing IOP is presently the evidence based, most accepted and most practised therapeutical approach for glaucoma patients. Currently topical ocular hypotensive medications, with its different classes, as well as filtering surgery (trabeculectomy and non-penetrating glaucoma surgery) are in the forefront of therapeutic modalities for IOP reduction. This article looks at the potential advantages and disadvantages of topical medications versus filtering surgery. It does not directly address the question of initial treatment of glaucoma, or what is the better treatment of glaucoma, as other review articles had, but rather looks in a more specific on the pros and the cons of each in relation to IOP reduction. In other words this article deals with the situation once the decision has been made to reduce IOP.

Postoperative 5-fluorouracil versus intraoperative mitomycin C in high-risk glaucoma filtering surgery: extended follow up

PURPOSE

To compare the long-term efficacy and safety of postoperative subconjunctival 5-fluorouracil (5-FU) injections with that of intraoperative mitomycin C (MMC) in eyes at high risk for failure of trabeculectomy.

METHODS

In a retrospective, non-randomized comparative trial, 36 eyes of 36 consecutive patients at high risk for failure of trabeculectomy underwent glaucoma filtering surgery with either postoperative subconjunctival 5-FU injections (19 eyes) or intraoperative application of MMC (17 eyes). Intraocular pressure, number of postoperative antiglaucoma medications, postoperative visual acuity, interventions, and complications were evaluated.

RESULTS

Overall success (intraocular pressure </=21 mmHg) at 1 year was 73.6% in the 5-FU group and 82.3% in the MMC group. The cumulative 4-year success was 52.6% in the 5-FU group and 60.5% in the MMC group (P = 0.6). At 4-year follow up, mean +/- SD intraocular pressures were 17.58 +/- 4.01 mmHg in the 5-FU group and 13.33 +/- 3.36 mmHg in the MMC group (P = 0.01). There was no significant difference in the number of post-operative medications (P = 0.84), appearance of blebs (P = 0.20), final visual acuity (P = 1.00), and complications (P > 0.05) between the groups.

CONCLUSIONS

These results suggest that both postoperative 5-FU injections and intraoperative MMC application have long-term success in high-risk patients. However, MMC results in a greater decrease in intraocular pressure than 5-FU.

Antifibrotics and wound healing in glaucoma surgery

When medical and laser therapy fail to control intraocular pressure, glaucoma filtration surgery needs to be performed. Glaucoma surgery is unique in that its success is linked to interruption of the wound-healing response in order to maintain patency of the new filtration pathway. In this article we will review the wound-healing pathway and the pharmacologic interventions that have been employed clinically and experimentally to interrupt wound healing, particularly steroids and the antifibrotic agents 5-fluorouracil and mitomycin C. A review of the published literature looking at use of these agents to enhance success as well as the associated complications are presented, critiqued, and interpreted in order to put the studies in proper perspective. Future directions and recommendations regarding use of these agents are available and an introduction to newer wound modulating agents such as anti-transforming growth factor beta 2 is presented.

Viscocanalostomy and phacoviscocanalostomy: long-term results

PURPOSE

To determine the safety and efficacy of viscocanalostomy and cataract extraction by phacoemulsification combined with viscocanalostomy (phacoviscocanalostomy) in the management of medically uncontrolled glaucoma.

SETTING

Department of Ophthalmic Surgery, Warrington Hospital, Warrington, England.

METHODS

This prospective nonrandomized study comprised 101 consecutive eyes of 73 patients with medically uncontrolled glaucoma having viscocanalostomy or phacoviscocanalostomy. Outcomes measured were intraocular pressure (IOP) control, visual acuity, gonioscopy, bleb morphology, and complications associated with surgery. Examinations were performed preoperatively and 1 and 7 days and 1, 3, 6, 9, and 12 months postoperatively and then at 6-month intervals. The mean follow-up was 23.9 months +/- 11 (SD) (range 6 months to 3.5 years).

RESULTS

The mean preoperative IOP was 24.9 +/- 5.7 mm Hg on 2.27 +/- 0.8 medications and the mean postoperative IOP at last follow-up, 16.14 +/- 2.9 mm Hg on 0.1 medications. A postoperative IOP of 21 mm Hg or less was achieved in 93% of eyes. In the remaining 7%, an addition of a mean of 1.4 medications achieved an IOP less than 21 mm Hg. No case required further glaucoma surgery. The mean percentage of IOP reduction in eyes having viscocanalostomy alone was 37% and in eyes having phacoviscocanalostomy, 33%. Complications were minor and included 4 small hyphemas, 5 small choroidal detachments, 1 iris prolapse through the phaco incision, and 10 intraoperative microperforations of the trabeculo-Descemet's window. Transient postoperative pressure elevations secondary to topical steroids occurred in 18% of eyes.

CONCLUSIONS

Viscocanalostomy and phacoviscocanalostomy were safe and effective in the surgical management of glaucoma and combined glaucoma and cataract. There was a low incidence of complications postoperatively and throughout the long-term follow-up.

Long-term follow-up of initial 5-fluorouracil trabeculectomy in primary open-angle glaucoma in Japanese patients

PURPOSE

To evaluate the long-term efficacy and safety of initial trabeculectomy with subconjunctival 5-fluorouracil in Japanese patients with primary open-angle glaucoma.

SUBJECTS AND METHODS

Clinical records of 117 eyes from 117 patients with records of up to 14 years were retrospectively analyzed using the appropriate statistical methods.

RESULTS

The mean follow-up period was 6.2 +/- 3.6 years. Criteria for successful intraocular pressure control and success probability by Kaplan-Meier method at 12 years were intraocular pressure < 21 mm Hg without medication plus a 30% or more reduction in intraocular pressure, 50.4 +/- 5.2% (SE) 38.2 +/- 5.3%; and intraocular pressure < 16 mm Hg without medication plus a 30% or more reduction in intraocular pressure, 45.9 +/- 5.1% (36.5 +/- 5.2%). Cox multiple regression analysis showed that a younger age was associated with a higher success probability (P <0.01). Eyes with lower postoperative intraocular pressure tended to show more positive value of the MD slope (P = 0.0669), whereas 7% of successfully treated eyes showed a negative postoperative MD slope (P < 0.1). The probabilities for developing bleb leaks and bleb-related infections in eyes with a functioning bleb were 28.9 +/- 12.5% and 13.0 +/- 10.4% at 12 years.

CONCLUSION

Trabeculectomy with 5-fluorouracil as an initial surgery in Japanese patients with primary open-angle glaucoma was effective for long-term control of glaucoma. However, the probability of late-onset bleb-related complications was not low in eyes with a functioning bleb, stressing the importance of constant care regarding bleb status.

Modulation of wound healing after glaucoma surgery

The healing process after glaucoma filtration is the main determinant of surgical failure and, even more important, the final intraocular pressure. The ability to fully control wound healing may ultimately give us the ability to set the intraocular pressure in the low teens for all patients undergoing glaucoma filtration surgery. The authors review the changes in how to use antimetabolites to improve safety, and many of the exciting new areas of progress, including growth factor neutralization and future molecular therapies to control wound healing.