Recent advances in trabeculectomy technique

Future research perspective on the interfacial physics of non-invasive glaucoma testing in pathogen transmission from the eyes

Non-contact tonometry (NCT) is a non-invasive ophthalmologic technique to measure intraocular pressure (IOP) using an air puff for routine glaucoma testing. Although IOP measurement using NCT has been perfected over many years, various phenomenological aspects of interfacial physics, fluid structure interaction, waves on corneal surface, and pathogen transmission routes to name a few are inherently unexplored. Research investigating the interdisciplinary physics of the ocular biointerface and of the NCT procedure is sparse and hence remains to be explored in sufficient depth. In this perspective piece, we introduce NCT and propose future research prospects that can be undertaken for a better understanding of the various hydrodynamic processes that occur during NCT from a pathogen transmission viewpoint. In particular, the research directions include the characterization and measurement of the incoming air puff, understanding the complex fluid-solid interactions occurring between the air puff and the human eye for measuring IOP, investigating the various waves that form and travel; tear film breakup and subsequent droplet formation mechanisms at various spatiotemporal length scales. Further, from an ocular disease transmission perspective, the disintegration of the tear film into droplets and aerosols poses a potential pathogen transmission route during NCT for pathogens residing in nasolacrimal and nasopharynx pathways. Adequate precautions by opthalmologist and medical practioners are therefore necessary to conduct the IOP measurements in a clinically safer way to prevent the risk associated with pathogen transmission from ocular diseases like conjunctivitis, keratitis, and COVID-19 during the NCT procedure.

[Comparison of new and old procedures in glaucoma surgery : Trabeculectomy, Preserflo and XEN]

Glaucoma is one of the most frequent causes of irreversible blindness worldwide. The main risk factor of the disease is an individually too high intraocular pressure and pressure reduction is still the only established treatment. If conservative pressure reduction and adherence are insufficient, and if the patient is unable to tolerate conservative treatment, surgical procedures become necessary. There are nowadays more than a dozen different surgical procedures for lowering the pressure. This article presents and discusses the procedures that have a subconjunctival pre-equatorial drainage in common. These include trabeculectomy, the XEN-gel implant and the Preserflo microshunt.

Oral Ibuprofen is Associated With Reduced Likelihood of Early Bleb Failure After Trabeculectomy in High-Risk Glaucoma Patients

PRCIS

Individuals prescribed ibuprofen after trabeculectomy have better postoperative intraocular pressure (IOP) control and a higher chance of bleb survival despite being at a higher risk of scarring.

PURPOSE

To investigate the effects of early adjunctive oral ibuprofen treatment on IOP and bleb failure in eyes at high risk of scarring.

METHODS

In these retrospective analyses, 288 eyes of 273 patients (mean ± SD age: 68.56 ± 10.47 y; 32.60% females) with primary glaucoma who underwent trabeculectomy/phacotrabeculectomy at the Singapore National Eye Centre between April 2020 and April 2021 with a follow-up duration ≥1 year were included. Of these, 77 (26.7%) eyes deemed to be at high risk of scarring were administered oral ibuprofen ≥3 months postoperatively (mean ± SD ibuprofen administration duration: 4.08 ± 2.28 wk). Participant's IOPs at baseline and at postoperative weeks 1, 2-3; and months 1, 2, 3, 6, and 12 were recorded. Bleb failure was defined as 2 consecutive IOP readings of >21, >18, and >15 mm Hg, and/or requiring remedial postoperative laser or surgery.

RESULTS

The ibuprofen group experienced significantly greater postoperative IOP reductions at week 1 [mean difference, 95%CI: -2.89 (-5.22, -0.56) mm Hg] and month 1 [-2.29 (-4.53, -0.05) mm Hg]; and substantially lower odds of bleb failure at the >18 mm Hg [odds ratio, 95% CI: 0.39 (0.20-0.79)] and >15 mm Hg [0.52 (0.29-0.94)] thresholds, compared with the non-ibuprofen group. No differences in adverse ocular hypotony events were observed.

CONCLUSION

Early adjunctive oral ibuprofen administered to individuals at high risk of posttrabeculectomy scarring is associated with greater IOP reductions and reduced likelihood of bleb failure. Our results suggest that oral nonsteroidal anti-inflammatory drugs may be a safe way of improving trabeculectomy survival in high-risk eyes.

Postoperative Complications in the Primary Tube Versus Trabeculectomy Study During 5 Years of Follow-up

PURPOSE

To describe postoperative complications encountered in the Primary Tube Versus Trabeculectomy (PTVT) Study during 5 years of follow-up.

DESIGN

Multicenter randomized clinical trial.

PARTICIPANTS

A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group.

METHODS

Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes).

MAIN OUTCOME MEASURES

Surgical complications, reoperations for complications, visual acuity, and cataract progression.

RESULTS

Early postoperative complications occurred in 24 patients (19%) in the tube group and 40 patients (34%) in the trabeculectomy group (P = 0.013). Late postoperative complications developed in 27 patients (22%) in the tube group and 32 patients (27%) in the trabeculectomy group (P = 0.37). Serious complications producing vision loss and/or requiring a reoperation were observed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P = 0.11). Cataract progression was seen in 65 patients (52%) in the tube group and 52 patients (44%) in the trabeculectomy group (P = 0.30). Surgical complications were not associated with a higher rate of treatment failure (P = 0.61), vision loss (P = 1.00), or cataract progression (P = 0.77) CONCLUSIONS: A large number of surgical complications were observed in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was higher following trabeculectomy with MMC than with tube shunt surgery. The rates of late postoperative complications, serious complications, and cataract progression were similar with both surgical procedures after 5 years of follow-up. Surgical complications did not increase the risk of treatment failure, vision loss, or cataract progression.

Endophthalmitis and blebitis following deep sclerectomy and trabeculectomy with routine use of mitomycin C

PURPOSE

The purpose of the study was to investigate the incidence for endophthalmitis and blebitis after deep sclerectomy (DS) and trabeculectomy with routine use of Mitomycin C (MMC) 0.4 mg/ml.

METHODS

Electronic medical records of patients who underwent surgery 1/2008-4/2020 were reviewed. Cumulative incidence for bleb-associated infection (BAI), including both endophthalmitis and blebitis, was calculated with cumulative incidence function (CIF) and Kaplan-Meier analysis. Risk factors for BAI were evaluated with univariate competing risk regression analysis and Log-rank analysis. Competing event in CIF was death.

RESULTS

In this retrospective single-centre cohort study, a total of 2653 patients and 3411 eyes underwent surgery: 3478 glaucoma surgeries, 2419 DS and 1059 trabeculectomies. Two cases of endophthalmitis and three of isolated blebitis developed. Median follow-up from the most recent surgery on the eye until the end of the study was 5.5 years, and until last visit at the ophthalmology department was 1.9 years. For the whole follow-up period in CIF-analysis, cumulative incidence for BAI was 0.16% (95% CI 0.06-0.36) at five years. Incidence was higher with eyes not treated with an antifibrotic during surgery (sub-hazard ratio 11.66, 95% CI 1.94-70.21, p = 0.007). Cumulative incidence between surgery and last visit with Kaplan-Meier analysis was 0.21% (95% CI 0.08-0.52) at five years, similarly, not using an antifibrotic increased incidence (Log-rank p < 0.001).

CONCLUSION

Cumulative incidence for BAI was low despite routine use of high-dose MMC.

The Norwich trabeculectomy study: risk factor analysis for the development of adverse, thin cystic blebs

PURPOSE

To investigate potential risk factors, particularly antimetabolite choice, with regard to the development of adverse bleb morphology in eyes that had undergone trabeculectomy surgery.

METHODS

A single-centre, observational cohort study of 631 consecutive eyes, which had undergone trabeculectomy over an 11-year period. For each case, bleb morphology was recorded at 2 years, and its association with the per-operative antimetabolite as well as potential confounding risk factors was analysed using univariate (unadjusted) and multivariate (adjusted) logistical regression analyses to identify those that could contribute to the development of adverse blebs. A standard protocol for 5-fluorouracil and mitomycin-C utilization was employed in the majority of cases.

RESULTS

When 5-fluorouracil was used (n = 257), 24% of patients formed cystic or partially cystic blebs, whereas with mitomycin-C (n = 299), only 12% formed such adverse blebs, the difference being statistically significant (OR = 3.54, p = 0.002 unadjusted; OR = 7.49, p = 0.00 adjusted). Of the other potential confounding factors, care within the private sector (OR = 0.30 p = 0.02) and a history of previous ocular surgery involving a conjunctival incision were identified as potential risk factors for the formation of adverse cystic blebs (OR = 0.28, p = 0.02).

CONCLUSIONS

Modern use of mitomycin-C appeared to be better than 5-fluorouracil as an adjunctive antimetabolite used at the time of trabeculectomy, with respect to the development of preferable final bleb morphology. The only potential preoperative risk factors found to be significant with respect to adverse cystic bleb development were care in the private health sector and previous ocular surgery involving a conjunctival incision.

Subtenon triamcinolone as an adjuvant in mitomycin-C-enhanced trabeculectomy in non-inflammatory glaucomas: A randomized clinical trial

This unicentric randomized clinical trial was designed to compare the surgical outcomes of mitomycin C-enhanced trabeculectomy (MMC-TRAB) with and without subtenon triamcinolone acetonide (TAAC) injection in patients with non-inflammatory glaucomas. This trial is registered at the Brazilian Registry of Clinical Trials (ReBEC) under the register number RBR-53f8nh. Consecutive non-inflammatory glaucoma patients requiring surgical intervention were randomized into two groups. In the control group, eyes underwent standard MMC-TRAB, while in the intervention group, besides the standard MMC-TRAB, these eyes also received a subtenon TAAC injection (4mg) close to the bleb site at the end of the surgery. The main outcomes of the study were surgical success rates, intraocular pressure (IOP) and number of medications at all timepoints. Success was defined as IOP ≤ 15 mmHg and subdivided in complete or qualified according to the need of medication. A total of 75 eyes of 63 different patients were included (intervention group = 39 eyes; control group = 36 eyes). There was no difference between groups at baseline (p>0.11). Multivariable regression analysis indicated that IOP levels were significantly lower in the intervention group at 18 and 24 months of follow-up when number of medications was considered as a covariate (P<0.001). Complete success rates were higher in the intervention group at 06 (90.9% vs 68.7%; p = 0.03), 12 (87.2% vs 66.7%; p = 0.02) and 18 months (87.2% vs 66.7%; p = 0.02). Additionally, although success rates at 24 months were higher in the intervention group (82.0% vs 66.7%; p = 0.09), this difference did not reach statistical significance. Qualified success rates did not significantly differ between groups at all timepoints. In conclusion, this study found significantly lower IOPs levels at 18 and 24 months of follow-up and higher complete success rates until 18 months of follow-up, with the use of subtenon TAAC as an adjuvant to standard MMC-TRABs in non-inflammatory glaucoma patients.

Post-trabeculectomy early bleb localization mimicking a 'ring of steel'

A 54-year-old-man underwent trabeculectomy with mitomycin-C (0.02%). At 4-week follow-up, there was an elevated, well-circumscribed bleb with raised intra-ocular pressure (IOP) of 32-mmHg, with a classic “ring of steel” appearance, typically seen in a tenon's cyst. A sub-tenon needle revision re-established aqueous flow. Two weeks later, the IOP was 8-mmHg without any anti-glaucoma medications. A diffuse well formed bleb was noted. Careful ocular examination helps to identify early post-operative localized bleb that may appear like a “ring of steel” but can be managed by needling, unlike a tenon's cyst, which would require more extensive intervention.

Primary trabeculectomy versus primary glaucoma eye drops for newly diagnosed advanced glaucoma: TAGS RCT

BACKGROUND

Patients diagnosed with advanced primary open-angle glaucoma are at a high risk of lifetime blindness. Uncertainty exists about whether primary medical management (glaucoma eye drops) or primary surgical treatment (augmented trabeculectomy) provide the best and safest patient outcomes.

OBJECTIVES

To compare primary medical management with primary surgical treatment (augmented trabeculectomy) in patients with primary open-angle glaucoma presenting with advanced disease in terms of health-related quality of life, clinical effectiveness, safety and cost-effectiveness.

DESIGN

This was a two-arm, parallel, multicentre, pragmatic randomised controlled trial.

SETTING

Secondary care eye services.

PARTICIPANTS

Adult patients presenting with advanced primary open-angle glaucoma in at least one eye, as defined by the Hodapp-Parrish-Anderson classification of severe glaucoma.

INTERVENTION

Primary medical treatment - escalating medical management with glaucoma eye drops. Primary trabeculectomy treatment - trabeculectomy augmented with mitomycin C.

MAIN OUTCOME MEASURES

The primary outcome was health-related quality of life measured with the Visual Function Questionnaire-25 at 2 years post randomisation. Secondary outcomes were mean intraocular pressure; EQ-5D-5L; Health Utilities Index 3; Glaucoma Utility Index; cost and cost-effectiveness; generic, vision-specific and disease-specific health-related quality of life; clinical effectiveness; and safety.

RESULTS

A total of 453 participants were recruited. The mean age of the participants was 67 years (standard deviation 12 years) in the trabeculectomy arm and 68 years (standard deviation 12 years) in the medical management arm. Over 65% of participants were male and more than 80% were white. At 24 months, the mean difference in Visual Function Questionnaire-25 score was 1.06 (95% confidence interval -1.32 to 3.43; p = 0.383). There was no evidence of a difference between arms in the EQ-5D-5L score, the Health Utilities Index or the Glaucoma Utility Index. At 24 months, the mean intraocular pressure was 12.40 mmHg in the trabeculectomy arm and 15.07 mmHg in the medical management arm (mean difference -2.75 mmHg, 95% confidence interval -3.84 to -1.66 mmHg; p < 0.001). Fewer types of glaucoma eye drops were required in the trabeculectomy arm. LogMAR visual acuity was slightly better in the medical management arm (mean difference 0.07, 95% confidence interval 0.02 to 0.11; p = 0.006) than in the trabeculectomy arm. There was no evidence of difference in safety between the two arms. A discrete choice experiment updated the utility values for the Glaucoma Utility Index. The within-trial economic analysis found a small increase in the mean EQ-5D-5L score (0.04) and that trabeculectomy has a higher probability of being cost-effective than medical management. The incremental cost of trabeculectomy per quality-adjusted life-year was £45,456. Therefore, at 2 years, surgery is unlikely to be considered cost-effective at a threshold of £20,000 per quality-adjusted life-year. When extrapolated over a patient's lifetime in a model-based analysis, trabeculectomy, compared with medical treatment, was associated with higher costs (average £2687), a larger number of quality-adjusted life-years (average 0.28) and higher incremental cost per quality-adjusted life-year gained (average £9679). The likelihood of trabeculectomy being cost-effective at a willingness-to-pay threshold of £20,000 per quality-adjusted life year gained was 73%.

CONCLUSIONS

Our results suggested that there was no difference between treatment arms in health-related quality of life, as measured with the Visual Function Questionnaire-25 at 24 months. Intraocular pressure was better controlled in the trabeculectomy arm, and this may reduce visual field progression. Modelling over the patient's lifetime suggests that trabeculectomy may be cost-effective over the range of values of society's willingness to pay for a quality-adjusted life-year.

FUTURE WORK

Further follow-up of participants will allow us to estimate the long-term differences of disease progression, patient experience and cost-effectiveness.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN56878850.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 72. See the NIHR Journals Library website for further project information.

Comparison of Surgical Outcomes of Sponge Application versus Subconjunctival Injection of Mitomycin-C during Combined Phacoemulsification and Trabeculectomy Surgery in Asian Eyes

Purpose:

To compare the outcomes of combined phacoemulsification–trabeculectomy surgery with intraoperative sponge-applied versus subconjunctival injection of mitomycin-C (MMC) in Asian eyes.

Methods:

This was a retrospective review of 95 eyes that consecutively underwent combined phacoemulsification–trabeculectomy surgery in a tertiary eye center in Singapore from January 2013 to June 2014. Data collected included intraocular pressure (IOP), best corrected visual acuity, and number of glaucoma medications. Outcome measures included postoperative IOP and complications at various timepoints up to 12 months after surgery.

Results:

Twenty eyes (21.1%) received 0.2 mg/ml subconjunctival MMC injection (“Group 1”) and 75 (78.9%) received 0.4 mg/ml sponge-applied MMC (“Group 2”). There was no difference between groups in demographics, IOP, and number of glaucoma medications preoperatively. There was a reduction in IOP at postoperative month (POM) 1, 6, and 12 in both the groups (POM12: Group 1, −2.8 ± 5.36 mmHg, P < 0.001; Group 2, −5.8 ± 6.29 mmHg, P = 0.054). At POM1, Group 2 showed a trend toward greater IOP reduction (−5.89 ± 7.67 mmHg vs. −1.55 ± 5.68 mmHg, P = 0.061). However, at both POM6 and POM12, there was no statistically significant difference in IOP reduction between the two groups. At POM12, complete success, defined as achieving an IOP of between 6 and 15 mmHg without the use of antiglaucoma medications, was achieved in 11 (55%) eyes in Group 1 and 48 (64%) in Group 2 (P = 0.9). There was a lower rate of postoperative hypotony in the Group 1 (0%) compared to Group 2 (8%) (P = 0.34).

Conclusion:

Combined phacoemulsification–trabeculectomy with subconjunctival MMC injection has comparable outcomes to that with sponge-applied MMC, with a similar reduction in IOP at 1, 6, and 12 months postoperatively and a lower postoperative complication rate.

Bleb grading by photographs versus bleb grading by slit-lamp examination

PURPOSE

Using a bleb-grading system clinically facilitates long-term follow-up of patients with previous glaucoma surgery. Clinical evaluation of these patients can be challenging for untrained ophthalmologists. Morphological bleb configuration might influence planning of follow-up visits in glaucoma patients due to different and individual prognosis after trabeculectomy. In this study, we compared the MaBAGS (Mainz Bleb Appearance Grading System), a classification system for filtering blebs with other classification systems (MBGS/Moorfields Bleb Grading System, IBAGS/Indiana Bleb Appearance Grading Scale) in reference to usability and reliability and compare it to grading by bleb photographs.

METHODS

Forty-two eyes of 31 patients after trabeculectomy were included. Three observers, two senior and one junior observer, graded all blebs using MaBAGS, MBGS and IBAGS during slit-lamp examination. Bleb photographs were reviewed at least 4 weeks after clinical examination. Statistical analysis was performed to determine agreement between the observers using intraclass correlation coefficients.

RESULTS

With MaBAGS, excellent and good levels of agreement were found for vascularity indices, Seidel test and transparency. Parameters for area and height yielded moderate agreement, while indices for conjunctival mobility and microcysts failed to show satisfying levels of agreement. Using MBGS resulted in excellent and good interobserver consistency for parameters regarding subconjunctival blood, Seidel test, and central and peripheral vascularity. Height and nonbleb vascularity reached moderate levels of agreement. Agreement for area parameters was low. With IBAGS, good levels of agreement were found for height and vascularity, and moderate for extent. In all grading systems, consistency was considerably better between the two experienced observers compared to the inexperienced grader.

CONCLUSIONS

MaBAGS shows good reproducibility. Using such a grading system improves precision of the description of a highly variable clinical finding. The reliability of grading by slit-lamp examination exceeds that of grading on photographs.

A Comparison of Trabeculectomy Surgery Outcomes With Mitomycin-C Applied by Intra-Tenon Injection Versus Sponge

PURPOSE

To compare the outcomes of mitomycin-C (MMC) delivered by intra-Tenon injection vs sponge application during trabeculectomy surgery.

METHODS

We retrospectively reviewed 566 patients with primary and secondary glaucoma diagnoses who received trabeculectomy surgery with MMC in an academic medical center. Exclusion criteria were age less than 18 years, no light perception vision, combined surgery, previous glaucoma incisional surgery, intraoperative 5-fluorouracil, or follow-up <1 month. Subjects were divided into 2 cohorts: MMC delivered by sponge application or by intra-Tenon injection. Main outcome measures were postoperative intraocular pressure (IOP) level and secondary measures were survival rate for IOP control, glaucoma medication use, complication rate, and vision.

RESULTS

After inclusion/exclusion criteria, 316 eyes were available for analysis; 131 eyes had MMC delivered via sponge and 185 eyes via injection. Mean postoperative IOP was not significantly different between treatment groups but change in IOP from baseline was lower in the sponge vs the injection group 24 months after surgery (P = .038). The MMC sponge group had significantly more tense, vascularized, or encapsulated blebs as a late complication (P = .046). Time to failure for postoperative IOP control was not significantly different between MMC treatment groups, but older patient age and limbus-based conjunctival incision were associated with significantly longer time to fail.

CONCLUSIONS

The application of MMC by injection was similar to application by sponge in lowering IOP in patients with glaucoma and the safety of both techniques appears to be comparable. Limbus-based conjunctival incision had longer time to failure for postoperative IOP control vs fornix-based incision. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Learning from the past: Mitomycin C use in trabeculectomy and its application in bleb-forming minimally invasive glaucoma surgery

Trabeculectomy has been performed since the mid-1960s and remains the gold standard for glaucoma surgery. Newer surgical options have evolved, collectively referred to as minimally invasive glaucoma surgeries. Despite producing large intraocular pressure decreases, full-thickness procedures into the subconjunctival space may be limited by fibrosis. Mitomycin C (MMC) and 5-fluorouracil have been in use with trabeculectomy with good evidence of significantly increased success at the cost, however, of an increased risk of complications. Off-label MMC application can be found in almost all clinical trials, including in combination with minimally invasive glaucoma surgeries. We explore current evidence for MMC use in trabeculectomy and how this may differ for minimally invasive glaucoma surgery devices and analyze the range of agents and doses that are used. Although we found that most studies could not show any correlation between MMC dosage and the surgical outcome, the success rates with the Xen® microshunt seemed to be higher when using 20 mcg of MMC than when using 10 mcg. Certain important methodological considerations make this hard to confirm definitively, and other factors such as placement of the device may play a more substantial role. For the PreserFlo® microshunt, preliminary data suggest higher success rates with higher MMC dosage at the cost of higher device-related adverse events and reoperations. Although the ideal dose still needs to be established, it seems very likely that MMC provides significant improvement in outcomes in bleb-forming minimally invasive glaucoma procedures.

Intraoperative injection versus sponge-applied mitomycin C during trabeculectomy: One-year study

Purpose

To determine the safety and efficacy of mitomycin C (MMC) injection versus sponge during trabeculectomy.

Methods

It is a prospective analysis of patients who underwent trabeculectomy with MMC and followed up for 1 year, divided into two groups, namely, group 1- injection (n = 21), group 2-> sponge (n = 21). The same concentration of MMC was used for both groups. Inclusion criteria were trabeculectomies with MMC for intraocular pressure (IOP) control in eyes with glaucoma (primary + secondary) with a follow-up of 1 year.

Results

Mean preoperative IOP in group 1 was 29.00 ± 11.92 mmHg and group 2 was 25.87 ± 11.09 mmHg, which reduced to 12.19 ± 4.03 and 15.56 ± 10.72 mmHg at final visit with P value of 0.0002 and 0.001, respectively. Mean preoperative number of antiglaucoma medications was 2.4 ± 0.87 in group 1 and 2.3 ± 0.96 in group 2, which reduced to 0.38 ± 0.5 and 0.91 ± 0.85 with P value of 0.001 and 0.0003, respectively. The complete success rate was 52.4% in the injection group and 26.1% in the sponge group at end of 1 year. Overall, success rate (complete + qualified) was 90.5% and 87% in group 1 and group 2 at final visit. All major complications were encountered in sponge group. 1 (11.1%) patient developed choroidal detachment and one had malignant glaucoma which got resolved by medical management. 33.3% cases had encapsulated bleb which received bleb needling. 44.4% cases underwent Argon laser suture lysis postoperatively.

Conclusion

The MMC injection may be as safe and as effective as conventional sponge application with comparable estimated complete treatment success.

Effect of the outer stent position on efficacy after minimally invasive transscleral glaucoma gel stent implantation

Purpose

The outer stent lumen can be located either deeper (in or under Tenon's layer) or more superficially in the conjunctival stroma after the transscleral XEN Glaucoma Gel Microstent (XEN‐GGM; Allergan Plc., USA) implantation. The present study aimed to investigate the effect of the postoperative conjunctival implant position on surgical success and intraocular pressure (IOP) after XEN‐GGM.

Methods

Prospective data from 66 consecutive open‐angle glaucoma eyes of 54 patients were collected preoperatively and 1 and 2 weeks, and 1, 6 and 12 months postoperatively. The layer of implantation was determined in the first month postoperatively as intra‐ and subtenon or intraconjunctival depending on the location of the outer lumen of the stent in OCT (Visante OCT; Zeiss, Germany). Primary outcome measures were differences in relative IOP reduction at 12 months between the two groups. Further, complete and qualified surgical success, number of secondary needlings and number of IOP‐lowering medications and absolute IOP were assessed.

Results

Relative IOP reduction was higher in intra‐ and subtenon group (n = 37/66, 56%) at week 1 (−54% versus −19%, p < 0.001), week 2 (−39% versus −21%, p = 0.02), month 1 (−42% versus −28%, p = 0.035) and month 12 (−39% versus −24%, p = 0.024). The mean absolute IOP was lower in intra‐ and subtenon group at week 1 (10.8 [95%CI, 8.8–14.1] versus 16.6 [95%CI, 14.1–19.0] mmHg, p < 0.001) and months 12 (13.9 [95%CI, 12.4–15.4] versus 16.7 [95%CI, 14.6–18.8] mmHg, p = 0.041). At month 6, a lower burden for IOP‐lowering medication was shown for the intra‐ and subtenon group (0.2 ± 0.5 versus 1.0 ± 1.1, p = 0.034). The mean number of secondary needlings, which were done in 47/66 (71%) of the eyes, was lower in the intra‐ and subtenon group in the first year (1.9 ± 1.7 versus 1.2 ± 1.2, p = 0.03). Qualified surgical success was higher in the intra‐ and subtenon group (90% versus 61%, p = 0.01) after 1 year.

Conclusion

The present study demonstrates a higher efficacy achieved with lower secondary needling rates in deeper implant positions in conjunctiva after XEN‐GGM.

Midterm outcome of single scleral suture technique in trabeculectomy and phacotrabeculectomy: a simplified approach

Purpose

To report outcome of trabeculectomy performed by single scleral suture in Indian eyes.

Methods

Non-randomized, non-masked, retrospective cohort analysis. Medical records of all consecutive patients who underwent trabeculectomy between 1 January 2011 and 31 December 2016 at CL Gupta Eye Institute, Moradabad (India), were reviewed and analyzed. Trabeculectomy was performed using single scleral suture for flap closure. The suture knot was buried inside sclera. The laser lysis of scleral suture was not done. Success was defined as complete success if an intraocular pressure (IOP) was >5 and ⩽21 mmHg without any glaucoma medications or re-surgery. Qualified success was defined as IOP ⩽21 mmHg with or without antiglaucoma medications.

Results

Data of 98 patients was analyzed. A total of 61 (62.2%) of them underwent trabeculectomy, and 37 (37.7%) underwent phacotrabeculectomy. The probability of complete success in patient underwent phacotrabeculectomy was 86% at 3 years, and in-patient underwent only trabeculectomy was 95% at 3 years. The probability of qualified success in patient undergone phacotrabeculectomy was 91% at 3 years, and in patient undergone only trabeculectomy was 97% at 3 years.

Conclusion

The mean postoperative IOP was significantly less then mean preoperative IOP, at all follow-up visits. This simplified technique also resulted in high midterm success probabilities with low complication rates.

Bleb-associated endophthalmitis: Proportion, presentation, management and outcomes in Victoria, Australia

IMPORTANCE

Bleb-associated endophthalmitis is a potentially vision-threatening complication of trabeculectomy. With improvements in surgical technique and changing patterns of intraoperative antimetabolite use, a re-evaluation of the incidence of bleb-associated endophthalmitis is warranted.

BACKGROUND

To investigate changes in the incidence, presentation, management and outcomes of bleb-associated endophthalmitis between 1997 and 2015 in Victoria, Australia.

DESIGN

A retrospective cohort analysis.

PARTICIPANTS

Consecutive cases of bleb-associated endophthalmitis managed at the Royal Victorian Eye and Ear Hospital (RVEEH) between 1997 and 2015.

METHODS

Medical record review of consecutive cases of bleb-associated endophthalmitis and statistical analysis were performed.

MAIN OUTCOME MEASURES

Visual acuity, including loss of light perception, intraocular pressure, and need for further surgery.

RESULTS

Sixty-seven eyes with bleb-associated endophthalmitis (BAE) were identified. Of these, 41 had trabeculectomy performed in Victoria during the study period, over which time 11 129 trabeculectomies were performed. The proportion of BAE was stable over time (0.4%). The mean age at presentation was 73.7 ± 12.1 years old and the majority of patients were Caucasian (79.1%). The mean duration between glaucoma filtration surgery and the development of bleb-associated endophthalmitis was 3 years (Interquartile Range = 0.4-6.0 years). The cultures were positive in 71.6% of cases. Approximately 1 in 8 patients required enucleation. The final visual acuity was poor with a Snellen Visual Acuity (VA) of 6/60 or worse in two-thirds of patients.

CONCLUSIONS AND RELEVANCE

Bleb-associated endophthalmitis is an uncommon complication following glaucoma filtration surgery. The proportion has remained stable over time. Visual outcomes remain poor.

One-month IOP in mitomycin C-augmented trabeculectomy can predict long-term IOP control in chronic primary angle-closure glaucoma

PURPOSE

To investigate the predictors of long-term intraocular pressure (IOP) in chronic primary angle-closure glaucoma (CPACG) treated with primary trabeculectomy.

METHODS

This study systematically reviewed cases of CPACG treated with primary trabeculectomy. The scleral flaps in all cases were sutured with two stitches in situ and two releasable sutures to ensure watertight under normal IOP conditions during surgery. Mitomycin C was used in all eyes. All patients were followed for 2 years. Digital massage of the bulbus and removal of the releasable suture were performed according to the IOP and shape of the filtering bleb. Demographic data and clinical outcomes were recorded. Factors predicting long-term IOP were identified.

RESULTS

A total of 72 patients (88 eyes) with a mean age of 58.51 ± 10.60 years were included in this study. The complete success rate was 89.77% after 2 years. The IOP began to stabilize after 7 days and reached its lowest point at the 1-month follow-up. The preoperative and early postoperative high or low IOP does not affect long-term effects (P > 0.05). There was a positive correlation between postoperative IOP at the 1-month and 2-year follow-ups (r = 0.64, P < 0.001).

CONCLUSION

In CPACG patients undergoing primary trabeculectomy, scleral flaps sutured watertightly with two stitches in situ and two releasable sutures under normal IOP conditions can ensure controllable, effective and safe treatment of CPACG. The preoperative and early postoperative high or low IOP does not affect long-term effects. One-month postoperative IOP can be used as a predictor of long-term IOP control.

Towards smart self-clearing glaucoma drainage device

For patients who are unresponsive to pharmacological treatments of glaucoma, an implantable glaucoma drainage devices (GDD) are often used to manage the intraocular pressure. However, the microscale channel that removes excess aqueous humor from the anterior chamber often gets obstructed due to biofouling, which necessitates additional surgical intervention. Here we demonstrate the proof-of-concept for smart self-clearing GDD by integrating magnetic microactuators inside the drainage tube of GDD. The magnetic microactuators can be controlled using externally applied magnetic fields to mechanically clear biofouling-based obstruction, thereby eliminating the need for surgical intervention. In this work, our prototype magnetic microactuators were fabricated using low-cost maskless photolithography to expedite design iteration. The fabricated devices were evaluated for their static and dynamic mechanical responses. Using transient numerical analysis, the fluid-structure interaction of our microactuator inside a microtube was characterized to better understand the amount of shear force generated by the device motion. Finally, the anti-biofouling performance of our device was evaluated using fluorescein isothiocyanate labeled bovine serum albumin. The microactuators were effective in removing proteinaceous film deposited on device surface as well as on the inner surface of the microchannel, which supports our hypothesis that a smart self-clearing GDD may be possible by integrating microfabricated magnetic actuators in chronically implanted microtubes.

Viscodilation of Schlemm's canal for the reduction of IOP via an ab-interno approach

Purpose

The aim of this study was to compare the 1-year efficacy and safety profile of ab-interno canaloplasty (ABiC) when performed as a stand-alone procedure or as an adjunct to cataract extraction in reducing IOP and glaucoma medication dependence.

Patients and methods

This retrospective, comparative, consecutive case series included patients with uncontrolled primary open-angle glaucoma (POAG) who underwent ABiC as a stand-alone procedure or in conjunction with cataract extraction. Data were collected over a 12-month period. Primary outcome measures were mean lower IOP and mean number of glaucoma medications. Secondary endpoints included surgical and postsurgical complications and secondary interventions.

Results

The study included 75 eyes of 68 patients (mean age: 73.7±9.9 years) with a mean baseline IOP of 20.4±4.7 mmHg on 2.8±0.9 medications, which reduced to 13.3±1.9 mmHg (n=73) on 1.1±1.1 medications at 12 months postoperative (both P<0.0001). At 12 months, 40% of eyes were medication free. In the ABiC/phacoemulsification subgroup (n=34 eyes), the mean IOP and medication use decreased from 19.4±3.7 mmHg on 2.6±1.0 medications preoperatively to 13.0±1.8 mmHg on 0.8±0.2 medications at 12 months (both P<0.001). In the stand-alone ABiC subgroup (n=41), the mean IOP and medication use decreased from 21.2±5.3 mmHg on 3.0±0.7 medications preoperatively to 13.7±1.9 mmHg on 1.3±1.1 medications at 12 months (P=0.001 and <0.001, respectively). No serious adverse events were recorded.

Conclusion

These data demonstrate that ABiC was effective at reducing IOP and medication use in eyes with uncontrolled POAG with or without cataract surgery.

Treatment Outcomes of Mitomycin C-Augmented Trabeculectomy, Sub-Tenon Injection versus Soaked Sponges, after 3 Years of Follow-up: A Randomized Clinical Trial

PURPOSE

To report the 3-year outcome of trabeculectomy with mitomycin C (MMC)-soaked sponges versus intra-Tenon injection of MMC in eyes with uncontrolled primary open-angle glaucoma.

DESIGN

Randomized clinical trial.

PARTICIPANTS

Eighty-two consecutive patients with uncontrolled primary open-angle glaucoma.

METHODS

Participants were randomized either to intra-Tenon injection of 0.1 ml of 0.01% MMC (TI group) or 0.02% subconjunctival application of MMC-soaked sponges (TS group). Patients were followed up for 3 years after surgery. The data for 73 eyes were included in the final analysis.

MAIN OUTCOME MEASURES

The primary outcome measure was the surgical success, defined as intraocular pressure (IOP) more than 5 mmHg and <21 mmHg, and IOP reduction of 20% or more from baseline, no reoperation for glaucoma, and no loss of light perception vision. Secondary outcome measures were IOP, glaucoma medications, best-corrected visual acuity (VA), bleb morphologic features according to the Indiana Bleb Appearance Grading Scale, complications, and endothelial cell count changes.

RESULTS

The cumulative probability of success at 3-year follow-up was 72.2% in the TI group and 65.1% in the TS group (P = 0.30). Uncontrolled IOP was the most common reason for failure. The mean preoperative IOP was 22.4±4.6 mmHg with an average of 3.1±1.0 medications. At 3 years, final IOP was 15.3±3.7 mmHg in the TI group and 16.4±3.5 mmHg in the TS group (P = 0.55). Mean glaucoma number of medications was 0.9±1.1 and 1.1±1.1 in the TI and TS groups, respectively (P = 0.54). Blebs tended to be more diffuse (P = 0.032), less vascularized (P = 0.013), and more shallow (P = 0.012) after intra-Tenon injection. Visual outcomes and endothelial cell changes were similar in both groups (P = 0.47 and P = 0.94, respectively).

CONCLUSIONS

Although the success rate and IOP reduction were comparable with both techniques, bleb morphologic parameters were more favorable after intra-Tenon injection of 0.1 ml of 0.01% MMC.

The impact of conjunctival flap method and drainage cannula diameter on bleb survival in the rabbit model

PURPOSE

To examine the effect of cannula diameter and conjunctival flap method on bleb survival in rabbits undergoing cannula-based glaucoma filtration surgery (GFS).

METHODS

Twelve New Zealand White rabbits underwent GFS in both eyes. The twenty-four eyes were divided into four groups. Two of the four groups (N = 12) received limbus-based conjunctival flaps (LBCF), and the other two (N = 12) received fornix-based conjunctival flaps (FBCF). Six FBCF rabbit eyes were implanted with 22-gauge drainage tubes, and the other six were implanted with 26-gauge tubes. Likewise, six LBCF rabbits received 22-gauge drainage tubes and six received 26-gauge tubes. Filtration blebs were evaluated every three days by a masked observer. Bleb failure was defined as the primary endpoint in this study and was recorded after two consecutive flat bleb evaluations.

RESULTS

Group 1 (LBCF, 22- gauge cannula) had a mean bleb survival time (Mean ± SD) of 18.7 ± 2.9 days. Group 2 (LBCF, 26-gauge cannula) also had a mean bleb survival time of 18.7 ± 2.9 days. Group 3 (FBCF, 22-gauge cannula) had a mean bleb survival time of 19.2 ± 3.8 days. Group 4 (FBCF, 26-gauge cannula) had a mean bleb survival time of 19.7 ± 4.1 days. A 2-way analysis of variance showed that neither surgical approach nor cannula gauge made a statistically significant difference in bleb survival time (P = 0.634 and P = 0.874). Additionally, there was no significant interaction between cannula gauge and conjunctival flap approach (P = 0.874), suggesting that there was not a combination of drainage gauge and conjunctival flap method that produced superior bleb survival.

CONCLUSION

Limbus and fornix-based conjunctival flaps are equally effective in promoting bleb survival using both 22 and 26-gauge cannulas in the rabbit model. The 26-gauge drainage tube may be preferred because its smaller size facilitates the implantation process, reducing the risk of corneal contact.

Discovery, characterization and clinical utility of prostaglandin agonists for the treatment of glaucoma

Topical ophthalmic formulations of analogues of the endogenous arachidonic acid cyclooxygenase metabolite, PGF_2α , are the standard of care treatment for the blinding disease glaucoma. These are the most potent and efficacious medical therapies for lowering intraocular pressure (IOP), the most important risk factor identified for disease progression. They have few side effects and offer the convenience of once-a-day dosing. It was initially believed that endogenous PGs raised IOP and caused substantial ocular surface adverse effects. However, carefully designed experiments demonstrated that esterification of the carboxylic acid afforded potent and efficacious topical ocular hypotensive activity. The final hurdle to be overcome was improvement of the side effect profile. A hypothesis was advanced that the IOP-lowering effect of PGF_2α isopropyl ester was due to activation of its cognate PG-FP receptor, while side effects were largely due to promiscuous interaction with other PG receptors. This hypothesis was validated by modification of the ω chain (carbons 13-20) to a phenyl group. This provided the first marketed FP-class PG agonist analogue (FP-PGA) ocular hypotensive agent, latanoprost. Since the introduction of latanoprost into clinical medicine to lower and control IOP, a number of additional FP-PGAs have been discovered, characterized and marketed, including travoprost, tafluprost, unoprostone isopropyl ester and bimatoprost (an amide). LINKED ARTICLES: This article is part of a themed section on Eicosanoids 35 years from the 1982 Nobel: where are we now? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.8/issuetoc.

Role of trabeculectomy in advanced glaucoma: Whether we stand to consider it a bane or a boon today?

PURPOSE

To elucidate the role of trabeculectomy in advanced glaucoma.

MATERIALS AND METHODS

Only patients with primary open-angle glaucoma were selected. All patients who had cup-disc ratio of 0.9 or a near-total cupping were given a trial of aggressive maximum medical therapy for IOP control for at least 4 weeks. Target IOP was defined as ≤ 12 mm Hg. Patients who showed progression were included in the study. A total of 10 patients were selected. Trabeculectomy was performed using limbal-based conjunctival flap. Patients were followed up for a period of 2 years for visual acuity, intraocular pressure, visual fields, slit-lamp biomicroscopy and bleb morphology.

RESULTS

Mean preoperative intraocular pressure on five drugs was 21.7 ± 3.8 mm Hg (range 18-27 mm Hg) on maximum medical therapy. Mean post-operative intraocular pressure was 11 ± 1.78 mm Hg (range 9-13 mm Hg) and 11 ± 1.92 mm Hg (range 9-14 mm Hg) at 1 month and 6 months post-operatively, respectively. Post-operatively, the visual acuity remained stable in 17 patients. It dropped by 1 Snellen line in 2 patients and 2 Snellen lines in 1 patient, respectively, over a period of 6 months and later improved to 6/6P following cataract surgery. There was no defined visual field progression in any of the 20 patients.

CONCLUSION

Besides being a cost-effective alternative to medical management, trabeculectomy not only provides a better IOP control but also has a high safety profile when performed by an experienced surgeon.

The Influence of Scleral Flap Thickness, Shape, and Sutures on Intraocular Pressure (IOP) and Aqueous Humor Flow Direction in a Trabeculectomy Model

PURPOSE

Intraocular pressure and aqueous humor flow direction determined by the scleral flap immediately after trabeculectomy are critical determinants of the surgical outcome. We used a large-scale model to objectively measure the influence of flap thickness and shape, and suture number and position on pressure difference across the flap and flow of fluid underneath it.

METHODS

The model exploits the principle of dynamic and geometric similarity, so while dimensions were up to 30× greater than actual, the flow had similar properties. Scleral flaps were represented by transparent 0.8- and 1.6-mm-thick silicone sheets on an acrylic plate. Dyed 98% glycerin, representing the aqueous humor was pumped between the sheet and plate, and the equilibrium pressure measured with a pressure transducer. Image analysis based on the principle of dye dilution was performed using MATLAB software.

RESULTS

The pressure drop across the flap was larger with thinner flaps, due to reduced rigidity and resistance. Doubling the surface area of flaps and reducing the number of sutures from 5 to 3 or 2 also resulted in larger pressure drops. Flow direction was affected mainly by suture number and position, it was less toward the sutures and more toward the nearest free edge of the flap. Posterior flow of aqueous humor was promoted by placing sutures along the sides while leaving the posterior edge free.

CONCLUSION

We demonstrate a new physical model which shows how changes in scleral flap thickness and shape, and suture number and position affect pressure and flow in a trabeculectomy.

An Analysis of 3-Year Outcomes Following Canaloplasty for the Treatment of Open-Angle Glaucoma

Purpose

To report 3-year results investigating the safety and efficacy of canaloplasty for open-angle glaucoma.

Setting

University of Oklahoma, Dean McGee Eye Institute, Oklahoma, United States of America.

Design

Nonrandomized single-center retrospective chart review.

Methods

Adult open-angle glaucoma eyes underwent canaloplasty or combined cataract-canaloplasty surgery. A tensioning suture was placed into Schlemm's canal in all eyes. Primary endpoints included the mean IOP and mean number of glaucoma medications at each follow-up visit. Secondary endpoints included visual acuity and surgical/postsurgical complications.

Results

The study cohort included 277 eyes (mean age, 72.8 years). Overall, the mean baseline IOP of 19.7 mmHg was reduced to 14.3 mmHg,14.0 mmHg, and 15.2 mmHg at 1, 2, and 3 years, respectively (p < 0.001). The average medicine use was reduced from 2.1 preoperatively to 0.4 at 12 months, and 0.5 and 0.6 at two and three years, respectively (p < 0.001). The frequency of surgical and postsurgical complications was low with no serious adverse events recorded.

Conclusion

Canaloplasty was safe and effective in achieving long-term IOP reductions and reduced dependence on antiglaucoma medications.

Incidence of short-term complications and associated factors after primary trabeculectomy in Chiang Mai University Hospital

BACKGROUND

To determine the incidence of early postoperative complications and associated factors after primary trabeculectomy in Thai glaucoma patients.

DESIGN

This was a retrospective observational study performed in Chiang Mai University Hospital.

PARTICIPANTS

One hundred and eighteen glaucoma patients participated in the study.

METHODS

All glaucoma patients underwent primary trabeculectomy with mitomycin C (MMC) using fornix-based conjunctival flap technique between December 2011 and May 2013. Surgical complications during the first 3 months of follow-up were recorded, and associated risk factors were analyzed.

MAIN OUTCOME MEASURES

The incidence of posttrabeculectomy complications was the main outcome measure.

RESULTS

One hundred and eighteen eyes of 118 patients were included. Early postoperative complications developed in 55 eyes (56.7%). Complications included hypotony (25 eyes, 27.2%), serous choroidal detachment (CD) (14 eyes, 15.6%), subconjunctival hemorrhage (12 eyes, 13.0%), hyphema (11 eyes, 12.4%), bleb leak (8 eyes, 8.8%), encapsulated bleb (2 eyes, 2.2%), aqueous misdirection (1 eyes, 1.1%), corneal epithelial defect (1 eyes, 1.1%), and overfiltration (1 eyes, 1.1%). There were no reported cases of endophthalmitis or blebitis. Hypotony was associated with serous CD (P = 0.006), and hyphema was associated with neovascular glaucoma (NVG) patients (P = 0.009). NVG was not associated with the increased rate of surgical failure (P = 0.083).

CONCLUSIONS

The incidence of early complications after first-time trabeculectomy with MMC was high (56.7%) in this Thai clinic setting, but most were transient and self-limited conditions. The correlations between hypotony and CD as well as hyphema and NVG were compatible with the previous studies.

Effect of Porcine Chondrocyte-Derived Extracellular Membrane (CDECM) on Postoperative Wound Healing in an Experimental Rabbit Model of Glaucoma Filtration Surgery

PURPOSE

We investigated whether a chondrocyte-derived extracellular membrane (CDECM) could reduce postoperative scar formation in an experimental rabbit model of glaucoma filtration surgery.

METHODS

Thirty-six male New Zealand white rabbits underwent experimental glaucoma filtration surgeries on the right eye and were randomly divided into the following two treatment groups: the CDECM group was treated with subconjunctival injections of 0.1ml CDECM (25 mg/ml; n = 18 eyes), and the operation (OP) group was treated with subconjunctival injections of 0.1 ml balanced salt solution (n = 18 eyes). The left eyes were used as controls (n = 36 eyes). The effects of the CDECM on the experimental rabbit model were investigated using histopathological, immunochemical analyses and Western blotting analyses of the inflammation, fibrosis and angiogenesis.

RESULTS

On the 14th postoperative day, the eyes of the CDECM group displayed reduced vascularity and fibrosis compared with the OP group. The vascular endothelial growth factor (VEGF), CD31 and TNFβ immunostaining were also reduced in the CDECM group. The level of TNFα mRNA was increased in the OP group. On the 28th postoperative day, the eyes of the CDECM group also exhibited reduced vascularity and less inflammation and fibrosis than those of the OP group. The expressions of VEGF, CD31, macrophage, TNFβ and NF-κB p65 were also decreased in the CDECM group. The levels of TNFα mRNA significantly differ, and the level of matrix metallopeptidase 9 (MMP9) was increased in the OP group. To determine the specific upstream pathway that was associated with NF-κB activation due to glaucoma filtration surgery, we measured Akt, PKCs and MAPKs signaling. The phosphorylation of p38 MAPK was increased in the OP group, whereas this expression was decreased by CDECM treatment.

CONCLUSIONS

CDECM seems to suppress angiogenesis, inflammation and fibrosis, which were related to wound healing in the experimental rabbit model of glaucoma filtration surgery. This effect, resulting from the inhibition of NF-κB expression, may be the blocking of the p38 MAPK signaling pathway.

In vitro mitomycin C absorption and delivery with different sponge materials used in filtering surgery

PURPOSE

The purpose of this study is to evaluate and compare mitomycin C (MMC) absorption and delivery in different materials used in filtering surgery.

METHODS

This is an in vitro study comparing polyvinyl alcohol triangular sponges (TS6, TS8), polyvinyl alcohol fluid wicks (EFW), and absorbable gelatin sponges (AGS3, AGS5), from which five different types of transport units were obtained. Seven pieces of sponge of each transport unit type were obtained as follows: two transverse strips were obtained at 6 and 8 mm from the apex of TS and divided into three equal pieces; 4×4 mm pieces of EFW; 3×3 and 5×5 mm pieces of absorbable gelatin sponges were cut. Filter paper was placed on a precision scale (0.01 mg). The seven sponge pieces of each type were weighed three times consecutively in dry and wet states, the latter after immersion for 15 seconds in 0.2 mg/mL MMC. The difference between the weights of the dry and wet filter paper at the end of each measurement sequence was also calculated and considered as an estimate of the amount of mitomycin delivered.

RESULTS

The amounts of MMC absorbed by each transport unit were as follows: (mean ± standard deviation) 27.43±5.13 for TS6, 31.91±6.63 for TS8, 15.96±2.23 for EFW, 17.96±2.05 for AGS3, and 33.81±2.05 for AGS5. The amounts of MMC delivered to the filter paper were as follows: 21.70±2.84 for TS6, 23.83±4.03 for TS8, 12.93±1.75 for EFW, 14.69±1.79 for AGS3, and 27.30±1.58 for AGS5.

CONCLUSION

Percentage MMC delivered was similar for all materials, but there was a tendency for greater delivery using larger sponges and greater homogeneity in delivery with AGS5. No statistical differences were found in percentage delivered by the different transport materials.

Bleb-related infection revisited: a literature review

Bleb-related infection (BRI) is one of the serious complications of glaucoma filtering surgery. This literature review is aimed at the evaluation of recent studies related to BRI. The review presented and discussed risk factors, and clinical and laboratory diagnosis emphasizing advances in diagnostic techniques to detect and distinguish the disease as well as to initiate immediate intensive antibacterial treatment. Clinical features of recognized prognostic factors of visual outcome were also presented. The studies showed that the prognosis of blebitis is usually good, unless infection has progressed to endophthalmitis that would signify a poorer prognosis. Despite prompt and intensive treatment of patients with bleb-related endophthalmitis, the outcomes remain unsatisfactory especially with virulent organisms and low initial visual acuity. It has been recommended that early detection and treatment of risk factors and thorough patient education are indispensable in ensuring best prognosis in post-trabeculectomy patients.

Primary Congenital Glaucoma with Delayed Suprachoroidal Hemorrhage following Combined Trabeculotomy Trabeculectomy and 5-Fluorouracil

Background. Delayed postoperative suprachoroidal hemorrhage (DSCH) may occur following intraocular surgery for the treatment of glaucoma. It is considered to be a rare and debilitating event if not managed appropriately. Reported herewith is a case of Primary Congenital Glaucoma followed by DSCH with successful immediate surgical intervention and visual restoration. Patient and Method. An 8-month-old male child had bilateral Primary Congenital Glaucoma (PCG). Combined Trabeculotomy Trabeculectomy with 5-Fluorouracil (5FU) was performed. He developed delayed suprachoroidal hemorrhage (DSCH) within 24 hours after intraocular surgery which was drained. In addition, he developed exposure keratopathy and left amblyopia. Outcome. Resolution of the DSCH was seen with surgical drainage in addition to treatments for exposure keratopathy and amblyopia. These resulted in reduced intraocular pressure and improved visual acuities. Conclusion. There appears to be a difference in the overall management of PCG and DSCH between adults and children. A high index of suspicion as well as emergency surgical treatment for DSCH and associated conditions should be performed on pediatric patients that present with these challenges.

A nanopore membrane regulator device for laser modulated flow after glaucoma surgery

Glaucoma, the second most common cause of blindness in the world, is a multifactorial disease with several risk factors, of which intraocular pressure (IOP) is a primary contributing factor. Filtration surgery is one of the most effective means to significantly lower IOP compared to medical or laser treatments, and it is typically reserved for advanced disease. However, there are high rates of postoperative complications associated with the procedure, often from over- or under-filtration. To address these problems, the glaucoma drainage device regulator (GDDR) implant was developed to allow post-operative control of aqueous flow and IOP. The device, a tube with a nanopore membrane, is placed beneath the scleral flap. Postoperatively, the membrane surface can be ruptured with a laser to augment flow through the system. This feature allows adjustable control of aqueous flow and diminishes the risk of hypotony in the early postoperative period.

A comparative study of a modified filtering trabeculotomy and conventional trabeculectomy

Purpose

The objective of the study reported here was to evaluate the outcome of a modified filtering trabeculotomy (FTO) without iridectomy in open-angle glaucoma compared with that of conventional trabeculectomy (trab).

Patients and methods

Thirty eyes of 30 patients who underwent modified FTO were prospectively followed for 1 year and were compared with 87 conventional trab patients (87 eyes), matched for age and preoperative intraocular pressure (IOP). The FTO procedure consisted of a deep sclerectomy and trabeculotomy preserving the trabeculo-Descemet membrane, without iridectomy. Main outcome measures were complete success (IOP <18 mmHg and >/=30% IOP reduction, without medication), IOP, visual acuity, medication, complications, and subsequent surgeries.

Results

In the conventional trab group, the median preoperative IOP was 23.0 mmHg (interquartile range 20.0–27.0) with 3.0 (2.0–3.0) medications, compared with 23.0 mmHg (20.0–27.0) and 3.0 (2.8–4.0) in the modified FTO group. Median postoperative IOP at 12 months was 12.0 mmHg (10.0–13.0) in the conventional trab and 11.0 mmHg (8.0–14.0) in the modified FTO group (P=0.3). The complete success rate at 1 year was 83.1% and 79.3% in the conventional trab group and modified FTO group, respectively (P=0.8). The complications hypotony (20.7%, 24.1%), choroidal detachment (2.3%, 10.3%), and bleb scarring (17.2%, 13.8%), were present in the conventional trab group and modified FTO group, respectively.

Conclusion

The outcomes of reduced IOP and medications in the FTO group were not different to those in the conventional trab group over 1 year, but some complications were more often seen with the modified FTO technique. The new filtration trabeculotomy, however, has the advantage of avoiding iridectomy, thus reducing the risk of cataract formation, and may result in the development of more favorable blebs by controlling the flow over two resistance levels.

Surgical outcome of safe surgery system trabeculectomy combined with cataract extraction

PURPOSE

To determine the efficacy of safe surgery system trabeculectomy combined with manual small incision cataract surgery/phacoemulsification in primary glaucoma coexistent with cataract.

METHODS

This is a retrospective analysis of 105 cases who underwent single-site combined surgery between January 2008 and December 2009. Safe surgery system trabeculectomy with diffuse and posterior application of mitomycin C was performed in all cases. Cataract extraction was done either by Manual Small Incision Cataract Surgery (MSICS) or phacoemulsification. Main outcome measures were success rate of trabeculectomy, as determined by four different IOP goals and incidence of postoperative complications. Analysis was performed using R-2.15, and the significance was tested at 5% level.

RESULTS

The minimum follow-up period was 12 months. The overall success rates (with or without medication) when safe surgery system trabeculectomy was combined with MSICS were 91, 70, and 51% for IOP ≤18, ≤15, and ≤12 mm Hg, respectively, and target IOP was achieved in 72% cases. The mean IOP reduction was 43.8% with MSICS and 42.08% with phacoemulsification. The surgical outcome was not significantly different for both techniques. Postoperative complications were infrequent and comparable.

CONCLUSION

The Safe Surgery System Trabeculectomy combined with cataract surgery offers excellent IOP control with minimal postoperative complications. It offers an effective and improved solution for primary glaucoma coexistent with cataract found in developing countries.

Shallow Anterior Chamber After Trabeculectomy: Risk Reduction by Use of Removable Compression Sutures

PURPOSE

To evaluate the risk of shallow anterior chamber after trabeculectomy with removable compression sutures.

METHODS

A total of 263 eyes affected by primary open-angle glaucoma that was unresponsive to medical treatments were divided into 2 groups: 126 eyes were treated with conventional trabeculectomy (group A) and 137 with a modified surgery technique using 3 removable compression 10-0 nylon sutures (group B). All the participants received intraoperative antimetabolites (mitomycin 0.04%). Increased intraocular pressure (IOP) of >14 mm Hg in the eyes of group B patients was followed by removal of compression sutures. Best corrected visual acuity, slit lamp examination, IOP, and anterior chamber depth were evaluated 1, 7, 30, 60, 90, and 180 days after surgery.

RESULTS

On the first postoperative day, 12 eyes from group A (9.5%) exhibited a shallow anterior chamber with marked hypotony and no eyes in group B showed flat anterior chamber at any control evaluation (P<0.001). The day after surgery, group A showed a mean IOP of 5.3 mm Hg (± 2.02), whereas group B had a mean of 7.4 mm Hg (± 2.10). At 7 days postoperation, the values for IOP were 10.95 (± 1.55) and 11.7 mm Hg (± 1.66) in groups A and B, respectively. One month later, mean IOP was 11.05 mm Hg (± 1.08) for group A and 13.9 mm Hg (± 3.26) for group B. The surgeon removed the compression sutures from all eyes with IOP>14 mm Hg (90%). The day after suture removal, mean IOP decreased to 10.45 mm Hg (± 1.37). There was no significant statistical difference in visual acuity between the 2 groups at any point during follow-up (P>0.001). At 180 postoperative days the difference in mean IOP between the 2 groups was statistically significant (P<0.001).

CONCLUSIONS

The application of removable corneoscleral compression sutures during trabeculectomy reduced the risk of postoperative shallow anterior chamber and allowed for safe IOP control after the procedure giving further postoperative chance to reduce the intraocular pressure.

Trabeculectomy with versus without releasable sutures for glaucoma: a meta-analysis of randomized controlled trials

Background

The aim of this study was to compare the efficacy and tolerability of trabeculectomies performed with and without releasable sutures in the treatment of patients with uncontrolled glaucoma.

Methods

A comprehensive literature meta-analysis was performed, comparing trabeculectomies performed with and without releasable sutures. The primary efficacy measure was the weighted mean difference (WMD) in percentage intraocular pressure reduction (IOPR%) at the follow-up end point. The secondary efficacy measure was the risk ratio (RR) for complete and qualified success rates of trabeculectomy at the follow-up end point. Trabeculectomy tolerability estimates were measured by the RR for adverse events. All the outcomes were reported with a 95% confidence interval (CI).

Results

The WMD of the IOPR% from baseline was −4.56 (range −9.24–0.12) when trabeculectomies without releasable sutures were compared with trabeculectomies with releasable sutures. Trabeculectomies with releasable sutures were associated with numerically greater, but nonsignificant, efficacy in terms of lowered IOP compared with trabeculectomies without releasable sutures. The complete and qualified success rate of the two surgical procedures were comparable, with RRs of 0.92 (range 0.80–1.04) and 0.99 (range 0.89–1.11), respectively, at the follow-up endpoints. Trabeculectomies without releasable sutures were associated with a significantly higher frequency of hypotony and flat anterior chambers than trabeculectomies with releasable sutures, with pooled RRs of 4.04 (range 1.88–8.68) and 2.57 (range 1.25–5.30), respectively.

Conclusion

Although the two surgical procedures resulted in equivalent efficacy in IOP control, the trabeculectomies performed with releasable sutures were better tolerated than those without releasable sutures.

Application of canaloplasty in glaucoma gene therapy: where are we?

PURPOSE

Schlemm's canal (SC) inner wall is adjacent to the juxtacanalicular trabecular meshwork (TM) over their entire circumference. We seek to transfer reporter and therapeutic genes to these outflow-modulating tissues via canaloplasty surgery in live monkeys.

METHODS

A standard canaloplasty surgical approach was performed in cynomolgus monkeys using flexible canaloplasty catheters, modified for monkey eyes with a 175-μm outer diameter and an LED-lighted tip. A 6-0 prolene suture was used for the exact localization of SC. Trypan blue was injected during catheter withdrawal to document catheter placement within SC and to determine ease of injecting fluid into SC. Before, during, and after the injection, the position of the catheter and the anatomic details were video-captured with an externally positioned noncontact endoscopic imaging system and 50 mHz ultrasound biomicroscopy (UBM).

RESULTS

A 360° catheterization and injection of dye into SC was achieved. Suture, catheter, and trypan blue were imaged with the endoscope camera system and the catheter was also visualized with UBM. Trypan blue was seen in the SC over 5 clock hours after a 1 clock-hour insertion of the catheter.

CONCLUSIONS

A modified canaloplasty catheter device might be used for gene delivery to the SC/TM area without circumferential catheterization. Further studies comparing different delivery methods of the vector/transgene into the SC using canaloplasty are needed.

[Modern filtration surgery. An update]

Preoperative treatment with steroids and nonsteroidal anti-inflammatory drugs increases the success of filtration surgery. Surgery with the patient under subconjunctival anesthesia is safe. Intraoperative application of mitomycin C is state of the art and enhances success rates. Perioperative use of bevacizumab seems to attenuate postoperative fibrosis. Postoperative hypotension is avoided by stable fixation of the scleral flap followed by stepwise controlled suturelysis or release. Transconjunctival flap suturing allows fast and simple treatment of overfiltration. The shorter the time lag between trabeculectomy and subsequent cataract surgery the higher the probability of bleb failure will be. The number of antiglaucomatous drugs and severity of glaucomatous damage before surgery correlate with the probability of failure and blindness.

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.

A Potential Application of Canaloplasty in Glaucoma Gene Therapy

Canaloplasty, a recently developed non-penetrating glaucoma surgical approach, may restore physiological outflow routes in primary open-angle glaucoma with less risk of severe postoperative complications than trabeculectomy. Since the inner wall of Schlemm's canal (SC) is directly in contact with the trabecular meshwork (TM) for 360 degrees and the catheter device used in canaloplasty allows viscoelastic to be injected into the entire length of SC, canaloplasty might also be used to perform SC/TM-targeted delivery of transgene vectors for glaucoma gene therapy. This hypothesized new method for transgene delivery may give the transgene access to the entire inner wall of SC and the whole juxtacanalicular region of the TM and allow the transgene to be expressed in both the TM and SC without affecting the cornea, iris and ciliary body. Further, this strategy might have a greater trabecular outflow resistance-decreasing effect than either the genetic or surgical approach alone.

Connexin43 modulation inhibits scarring in a rabbit eye glaucoma trabeculectomy model

We investigated whether one subconjunctival injection of connexin43 antisense oligodeoxynucleotides (Cx43 AsODN) modulates postoperative scarring in a rabbit model of glaucoma trabeculectomy surgery. In a randomised, controlled, masked-observer study, 39 rabbits underwent trabeculectomy surgery with insertion of a 22-gauge cannula in the right eyes and were randomly divided into three treatment groups. Each rabbit received an injection of Cx43 AsODN in Pluronic gel, balanced salt solution or Pluronic gel alone into the formed bled. The animals were euthanized at 8 and 24 h and at 5 and 21 days. Histology and immunohistochemistry results demonstrated that Cx43 AsODN decreased Cx43 upregulation at 8 and 24 h which led to less myofibroblast upregulation at days 5 and 21 and reduced scarring at day 21 compared to controls. We conclude that postoperative use of Cx43 AsODN inhibited subconjunctival scarring and fibrosis. Cx43 AsODN injection may be a safe and effective anti-scarring agent in glaucoma trabeculectomy surgery.