A randomised, prospective study comparing trabeculectomy with viscocanalostomy with adjunctive antimetabolite usage for the management of open angle glaucoma uncontrolled by medical therapy

Viscocanalostomy and combined phacoemulsification with viscocanalostomy: A five-year follow-up

Purpose:

To assess the effectiveness and safety of viscocanalostomy (VC) and phaco-viscocanalostomy (PV) surgeries in eyes with a five-year follow-up.

Methods:

Retrospective review of patients who underwent VC and PV between January 2010 and December 2012 in the Stanley Eye Unit Abergele, UK. Patients were included for the analysis if they had a full 5-year follow-up or required redo surgery in the 5-year period. Success was defined as an intraocular pressure (IOP) of <21 mmHg. The subanalysis included IOP <16 mmHg, IOP reduction >20%, and IOP reduction >30%, the complication rate, and the drop in the use of glaucoma medications post-surgery.

Results:

A total of 370 eyes from 303 patients were included for the analysis. The mean preoperative IOP was 23 mmHg ± 5.3 mmHg with an average of 3.0 ± 0.1 medications. By year 5, this was reduced to 14.3 mmHg ± 6.5 mmHg with a mean of 1.0+/- 0.9 medications; 47.8% of the eyes had an IOP of <21 mmHg by year 5 without medication with a total of 92.6% of the eyes reaching this target with medication. The main complication in this group was the perforation of the Trabeculo Descemet’s Window (TDW) but this was not associated with a poorer outcome.

Conclusion:

This large data set of eyes undergoing VC surgery demonstrates the effectiveness and safety of this technique over 5 years.

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.

Outcomes of Phaco-viscocanalostomy in Primary Open Angle Glaucoma versus Pseudoexfoliation Glaucoma

Purpose

Viscocanalostomy represents an alternative to standard penetrating glaucoma surgery. The aim of this study is to compare the outcomes of combined phacoemulsification and viscocanalostomy in eyes with primary open-angle glaucoma (POAG) versus eyes with pseudoexfoliation glaucoma (PEXG).

Methods

In this prospective non-randomized comparative study, eyes with cataract and POAG or PEXG were enrolled. Pre- and postoperative data including best corrected visual acuity (BCVA), intraocular pressure (IOP), and the number of antiglaucoma medications administered were recorded at each visit. All patients underwent phacoviscocanalostomy. Complete success was defined as the IOP of 21 mmHg or less without the administration of medication while a qualified success reported the same IOP parameters either with or without the administration of medication.

Results

Fifty-four eyes with POAG and fifty-four with PEXG underwent phacoviscocanalostomy. The mean follow-up time was 23.36 ± 8.8 months (range, 6-40 months). The mean postoperative IOP reduced significantly in both groups, although the mean IOP reduction was significantly greater in PEXG eyes (14.7 ± 8.9 vs 10.1 ± 7.7 mmHg) (P = 0.05). At the final follow-up visit, the mean postoperative IOP was 14.1 ± 2.1 and 16.6 ± 3.5 mmHg in the PEXG and POAG eyes, respectively (P = 0.001). A complete success rate of 88.9% and 75.9% was achieved in PEXG and POAG eyes, respectively (P = 0.07). The qualified success rate was 100% in the PEXG and 85.2% in POAG groups (P = 0.03).

Conclusion

Phacoviscocanalostomy achieved significant IOP reduction and visual improvement in both POAG and PEXG patients. Our results indicated that in terms of IOP reduction, this procedure was more effective in treating PEXG.

Deep sclerectomy and trabeculectomy augmented with Mitomycin C: 2-year post-operative outcomes

Purpose

Two-year post-operative outcomes of both deep sclerectomy (DS) and trabeculectomy surgery (Trab) augmented with Mitomycin C (MMC) at a single tertiary eye centre.

Methods

Retrospective review of DS + MMC and trabeculectomy + MMC at a single centre between February 2015 and March 2018. Patients with a minimum of 12-month follow-up were included. Post-operative follow-up: day 1, week 1, months 1/3/6/12/18/24. Primary outcomes: changes in intraocular pressure (IOP) and changes in LogMAR visual acuity (BCVA) pre- and post-procedure. Secondary outcomes: changes in number of eye drops, number of follow-up clinic visits, post-operative complications and further surgical interventions. Complete success: IOP ≤ 21 mmHg off all IOP-lowering medications. Qualified success: IOP ≤ 21 mmHg on medication. Failure: IOP > 21 mmHg at 24 months or ≤ 5 mmHg on 2 consecutive follow-up visits after 3 months +/− additional incisional glaucoma surgery +/− loss of light perception. Statistical analysis performed using Microsoft Excel + SPSS.

Results

90 eyes: DS + MMC = 46 eyes, Trab + MMC = 44 eyes. DS + MMC v Trab + MMC: mean pre-op IOP = 19.57 mmHg v 18.89 mmHg, significantly reduced at all post-operative time-points for both groups (p < 0.001). Mean IOP reduction from baseline = 33.94% v 38.39%; > 30% IOP reduction = 54.35% v 68.18%. IOP ≤ 16 mmHg = 82.61% (38/46) v 95.46% (42/44), IOP ≤ 12 mmHg = 52.17% (24/46) v 72.72% (32/44). Complete success = 67.39% v 61.36%, qualified success = 26.09% v 29.55%, failure = 6.52% v 9.09%. Post-op BCVA: no statistically significant differences between two groups (p = 0.09). Mean pre-op drops v post-op drops = 2.98 v 0.38 (DS + MMC; p < 0.001); 2.68 v 0.39 (Trab + MMC; p < 0.001). Further surgical intervention = 13% v 29.55%. Mean number of post-op clinic visits DS + MMC v Trab + MMC = 10.09 v 13.02 (p = 0.005).

Conclusion

Both procedures achieve sustained intraocular pressure and drop reduction at 2 years post-op. DS + MMC has lower complication rates requiring less intervention and significantly fewer clinic visits, which may be an important factor for deciding surgical management of glaucoma patients in the era of Covid-19 to reduce patient/clinician exposure to the virus.

Chemokine (C-C motif) ligand 2 and chemokine (C-C motif) ligand 7 in angle-closure glaucoma

PURPOSE

To compare the concentrations of chemokine (C-C motif) ligand 2 (CCL2) and chemokine (C-C motif) ligand 7 (CCL7) in aqueous humour of eyes with acute primary angle-closure (APAC), primary angle-closure glaucoma (PACG) or with age-related cataract.

METHODS

The prospective investigation included a study group of 56 patients (24 patients with APAC; 32 patients with PACG) undergoing glaucoma surgery and a control group of 21 patients undergoing routine cataract surgery. The interval between glaucoma attack and trabeculectomy was 19.4 ± 9.8 days.

RESULTS

The concentrations of CCL2 (3037 ± 501 versus 1127 ± 141 pg/ml; p = 0.003) and CCL7 (10.5 ± 2.4 versus 2.8 ± 0.4 pg/ml; p < 0.001) were significantly higher in the APAC group than in the PACG group, while the concentrations of both cytokines did not differ significantly between the PACG group and the control group (CCL2: 1190 ± 98 pg/ml; p = 0.10; CCL7: 2.0 ± 0.6; p = 0.18). The concentrations of both cytokines were significantly and inversely correlated with the interval between the acute angle-closure attack and surgery (CCL2: p = 0.02; ρ = -0.48; CCL7: p = 0.04; ρ = -0.42). Higher CCL2 concentrations were associated with higher prevalence of surgical failure (28.6% versus 7.1%; p = 0.036).

CONCLUSIONS

Concentrations of CCL2 and CCL7 as major inflammatory cytokines with potential influence on the risk of filtering surgery failure were significantly elevated after an acute glaucoma attack and decreased with longer interval to the attack. Trabeculectomy may have a lower risk of failure if performed later than earlier after an acute glaucoma attack, with lower CCL2 concentrations associated with better surgical outcome.

Outcomes of Nd: YAG Goniopuncture After Viscocanalostomy/Phacoviscocanalostomy

PURPOSE

The aim of this study is to evaluate the safety and efficacy of laser goniopuncture (LGP) to lower intraocular pressure (IOP) post-viscocanalostomy (VC)/phacoviscocanalostomy (PVC). Outcomes include: IOP reduction from pre-LGP levels and the need for further topical antiglaucomatous medication or surgery.

PATIENTS AND METHODS

A total of 541 eyes that underwent VC/PVC between 2009 and 2012, at the Stanley eye unit in Abergele were included in the study.

INCLUSION CRITERIA

All patients who had LGP at any timepoint after VC/PVC when target IOP was not achieved +/- progression in visual field with at least 6 months of follow-up data.Statistical analysis was performed on IOP values pre- and post-LGP, involving χ, Fischer exact, Mann-Whitney U, and Wilcoxon tests. A P-value of <0.05 was accepted as the level of significance.

RESULTS

Of the 515 included eyes, 136 (26%) required LGP after a mean of 15.11±9.73 months after surgery (95% confidence interval, 13.46-16.76 mo), ranging from 1 to 42 months. LGP reduced IOP significantly from a mean of 22.92±5.80 to 17.08±5.30 mm Hg immediately for all eyes, a reduction of 5.84 mm Hg (or a 25% reduction) (P<0.0001). IOP significantly reduced in the VC group with a mean reduction of 7.60 mm Hg compared with 4.85 mm Hg in the PVC group immediately after the procedure (P=0.0038). LGP was required sooner in the VC group compared with PVC, 11.35 and 14.57 months, respectively (P=0.0393). A total of 69 (62%) eyes were commenced on topical IOP-lowering medications, mean 7.26±6.41 months after LGP.

CONCLUSIONS

This study supports previous evidence that LGP enhances the IOP-lowering success of VC/PVC. The advantages of LGP are that it is a minimally invasive clinic-based procedure with a low complication rate.

Intraindividual comparison of Canaloplasty versus trabeculectomy with mitomycin C in a single-surgeon series

PURPOSE

To compare the safety, efficacy, and postoperative management of canaloplasty in one eye versus trabeculectomy with mitomycin C in the contralateral eye in patients with open-angle glaucoma.

METHODS

This study was a consecutive case series of 30 eyes of 15 patients who had prior trabeculectomy with mitomycin C (group II) and later were treated with canaloplasty (group I) in the fellow eye. Primary outcome measures included intraocular pressure (IOP) and glaucoma medication after 6- and 12-month follow-up. Secondary outcome measures were number of postoperative interventions, hospitalization, and follow-up visits.

RESULTS

Mean preoperative IOP±SD was 26.73±6.4 mm Hg in group I and 26.3±10.9 mm Hg in group II (P=0.9), which decreased to 13.21±2.83 mm Hg for canaloplasty (P<0.0001) and 11.64±5.2 mm Hg for trabeculectomy (P<0.0005) including 3 patients with hypotony at 12 months. Glaucoma medication decreased from 2.5 in group I and 2.7 in group II to no medication in group I and 0.36±0.74 supplemental medication in group II 12 months postoperatively (P<0.0001). Best corrected visual acuity (±SD) was logMAR 0.06±0.09 (group I) and 0.28±0.56 (group II) before and logMAR 0.07±0.09 (group I) and 0.31±0.58 (group II) after surgery. In group I, 2 interventions were necessary. In group II, 8 eyes needed 112 interventions for filtering bleb management. Although canaloplasty took significantly longer to perform, trabeculectomy group required a longer initial postoperative hospitalization (mean 10.4 vs. 5.4 d, P<0.0001) and more postoperative follow-up visits (mean 3.9 vs. 8.5, P<0.001).

CONCLUSIONS

Canaloplasty and trabeculectomy were both effective in lowering IOP. However, less follow-up visits and significantly fewer complications and interventions were favorable for canaloplasty.

A comparative study of trabeculectomy and the new clear-cornea filtering procedure, intrastromal diathermal keratostomy (IDK)

PURPOSE

For the first time to compare the 1-year success rates of trabeculectomy and the new clear-cornea filtering procedure, intrastromal diathermal keratostomy (IDK).

METHODS

Prospective clinical observational study including 99 consecutively operated eyes (69 patients) with well-established primary open-angle glaucoma referred for filtering operation. We compared the change in intraocular pressure (IOP), number of anti-glaucomatous medication, complications and reoperations after 1 year. Seventy-four eyes were operated with trabeculectomy, and 25 with IDK. Complete success was defined as IOP ≤ 18 mmHg, IOP lowered ≥ 30%, no medication and no reoperation. Qualified success was defined as IOP ≤ 18 mmHg, and IOP lowered ≥ 30% with or without medication or reoperation.

RESULTS

Intraocular pressure pre- and postoperatively in the trabeculectomy group was 25.3 and 14.1 mmHg versus 23.8 and 15.8 mmHg in the IDK group. The number of medications pre- and postoperatively in the trabeculectomy group was 3.1 and 0.5 versus 3.2 and 1.3 in the IDK group. Forty-four (59%) of the eyes in the trabeculectomy group met the complete success criteria compared with 5 (20%) in the IDK group (p < 0.01). Sixty-eight (92%) in the trabeculectomy group and 16 (64%) in the IDK fulfilled the qualified success criteria (p < 0.01).

CONCLUSION

Both the complete and qualified 1-year success rates of IDK are significantly lower compared with the success rates of trabeculectomy. The IDK does not reduce the IOP as much as the procedure of trabeculectomy, and it carries a higher frequency of reoperations and more medication postoperatively. Thus, our prospective data do not support the procedure of IDK as 'the gold standard' for filtering surgery in patients with open-angle glaucoma.

Clinical options for the reduction of elevated intraocular pressure

Elevated IOP in clinical practice is usually seen in glaucoma or ocular hypertension. Glaucoma affects 60 million people worldwide and 8.4 million are bilaterally blind from this chronic disease.1 Options for reducing IOP rely on pharmacological agents, laser treatments and surgery which may be penetrating or non-penetrating. The last twenty years has seen significant changes in all of these strategies. This review aims to cover these clinical options and introduce some of the new technologies currently in development for the clinical lowering of IOP.

Systematic overview of the efficacy of nonpenetrating glaucoma surgery in the treatment of open angle glaucoma

BACKGROUND

To evaluate the intraocular pressure (IOP)-lowering effects achieved by nonpenetrating glaucoma surgery (NPGS) and its modifications in patients with open angle glaucoma.

MATERIAL/METHODS

Randomized controlled trials evaluating patients with primary and secondary open angle glaucoma treated with NPGS were identified through systematic searches. The main outcome measures were the percentage IOP reduction and the complete success rate. Complete success was defined as target endpoint IOP (usually less than 21 mm Hg) without medications. The pooled estimates were calculated using the random effects model.

RESULTS

Both deep sclerectomy (DS) and viscocanalostomy (VCO) were less effective than trabeculectomy (TE) in lowering IOP, with the percentage IOP reductions at 2 years being 35.2% for DS, 30.2% for VCO, and 45.6% for TE. Intraoperative use of implants and mitomycin C (MMC) increased IOP-lowering effects of DS, with IOP reductions at 2 years of 41.1% and 41.7%, respectively. The complete success rates at 4 years were 35.4% for DS, and 22.7% for VCO, lower than that of TE (47.6%). The complete success rates of DS with implants and MMC of 64.6% and 52.1%, respectively, at 4 years, were greater than that of primary DS. NPGS caused major complications in fewer patients than did TE.

CONCLUSIONS

Primary deep sclerectomy and primary viscocanalostomy, which can significantly lower IOP, were associated with fewer complications than was TE. However, the IOP-lowering effects of both NPGS seem to be lower than that of primary TE. The efficacy of DS can be improved with the intraoperative use of implants and MMC.

A history of the surgical management of glaucoma

Many new surgeries have been devised since 1856, when von Graefe discovered that iridectomy is an effective surgical method for acute glaucoma treatment. Two years later, De Wecker presented sclerotomy as a procedure for chronic glaucoma. In 1900, internal filtration (cyclodialysis) was developed. In 1932, ciliodestruction was suggested. The four approaches, relief of pupillary block, external filtration, internal filtration, and ciliodestruction, are still the basic techniques of glaucoma surgeries over 100 years later. There have been two basic approaches to lowering eye pressure surgically: increase outflow and decrease inflow of aqueous humor. Although the majority of surgeries used nowadays were introduced in the 1960s, their roots can be traced to the work of surgeons in the 19th century. Trabeculectomy, in use since the mid-1960s, is the most effective glaucoma surgery in terms of intraocular pressure reduction but carries its own limitations. Non-penetrating glaucoma surgeries emerged at the same time trabeculectomy was presented, but they are not used as commonly as trabeculectomy. Molteno introduced the first effective shunt and followed by others. Since 1995, the majority of new surgeries have consisted of new implantable devices including SOLX, iStent, and Ex-PRESS shunt. This article will review the history of glaucoma surgery and describe the fundamentals of different glaucoma procedures.

Phacoviscocanalostomy in pseudoexfoliation glaucoma versus primary open-angle glaucoma

OBJECTIVE

To compare the outcome of phacoviscocanalostomy in pseudoexfoliation glaucoma (PEXG) versus that in primary open-angle glaucoma (POAG).

DESIGN

Prospective comparative study.

PARTICIPANTS

Sixty eyes of 60 patients who underwent phacoviscocanalostomy for cataract and medically uncontrolled PEXG (30 eyes) or POAG (30 eyes).

METHODS

Success rate was based on intraocular pressure (IOP) reduction and need for antiglaucoma medication. Visual acuity (VA) and complication rates were secondary outcomes.

RESULTS

The mean follow-up was 19.7 months (range, 12-36 months). The mean IOP values in both groups were significantly less than the preoperative values at all postoperative intervals (p < 0.001). From 1 month onward, the decrease in IOP was more dramatic in PEXG eyes than in POAG eyes (p < 0.05). At last visit, the mean percentage of IOP reduction was 49.7% in the PEXG group and 30.9% in the POAG group. All study eyes required decreased antiglaucoma medications and showed improved VA postoperatively. Transient complications included Descemet's membrane microperforations, macroperforation, zonular dehiscence, and postoperative IOP spike. No eyes developed trabeculectomy-type bleb, hyphema, fibrin exudation, or bleb-related complications.

CONCLUSIONS

Phacoviscocanalostomy achieved excellent IOP control and VA improvement in both PEXG and POAG groups. PEXG demonstrated greater IOP reduction and fewer postoperative medications than POAG. The complication rate was low and did not affect surgical outcome. Phacoviscocanalostomy can be an effective and safe surgical alternative to phacotrabeculectomy in both groups of patients.

[Viscocanalostomy: preliminary clinical results]

PURPOSE

Filtration surgery has shifted in the past 20 years to a nonperforating surgery to reduce complications. The purpose of this study was to assess the short-term clinical results and complications of viscocanalostomy.

PATIENT AND METHODS

In a prospective and nonrandomized study, 107 consecutive eyes of 67 patients who underwent viscocanalostomy were analyzed. The surgeon conducted postoperative care. The minimal follow-up was 1 year, with a mean follow-up of 13.1 months (range, 12-18 months). The criteria for success were defined as intraocular pressure (IOP) less than 21 mmHg without treatment.

RESULTS

The mean preoperative intraocular pressure was 28.3 mmHg while the mean postoperative intraocular pressure was 5.4 mmHg on the first day and 10.2 mmHg at 13 months. The rate of patients who had intraocular pressure below 21 mmHg with or without treatment was 98% at 13 months. The complete success rate without treatment was 80% at 13 months. Seven cases of ocular hypotony lasting more than 1 month were noted.

CONCLUSION

Viscocanalostomy is a promising procedure because in the short term it provides good tonometric results in glaucomatous patients without the complications of trabeculectomy. However, it remains a technique with a learning curve.

Moving the goal posts definitions of success after glaucoma surgery and their effect on reported outcome

PURPOSE

To determine (1) the extent to which the definition of success of glaucoma surgery varies in the literature and (2) the degree to which the reported outcome after trabeculectomy is affected by the criteria used to define success.

DESIGN

A systematic review of the literature and application of definitions to a retrospective cohort.

PARTICIPANTS

A cohort of 100 patients who previously underwent trabeculectomy.

METHODS

A literature search was performed of PubMed using the search term trabeculectomy for a 5-year period. Studies presenting original data relating to longitudinal intraocular pressure (IOP) control after glaucoma surgery were included. The definitions of success and failure used were documented for each publication. Each IOP-related definition of success was applied to a cohort of patients who previously underwent trabeculectomy. Success rates were derived for each published definition up to 36 months after surgery.

MAIN OUTCOME MEASURES

Intraocular pressure measured by Goldmann applanation tonometry.

RESULTS

From 100 publications meeting the inclusion criteria, 92 distinct IOP-related definitions of success were identified. Using these definitions, success rates for this series of 100 trabeculectomies varied between 36.0% and 98.0% after 3 years of follow-up.

CONCLUSIONS

Over a recent 5-year period, there were nearly as many different definitions of success after glaucoma surgery as publications on the subject. The definition used markedly affects the quoted success rate after trabeculectomy, making interpretation of and comparison between published results extremely difficult. Standardization of published outcome parameters after glaucoma surgery is essential to allow meaningful comparisons between different study reports.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Canal surgery in adult glaucomas

PURPOSE OF REVIEW

Outflow procedures for glaucoma surgery have remained popular in the last decade, including trabeculectomy, glaucoma drainage devices, and deep sclerectomy/viscocanalostomy. In the last few years, the surgical armamentarium for glaucoma has vastly increased. Surgeons are using more procedures aimed at creating bleb-free surgery. Schlemm's canal surgery is experiencing a renaissance. This article concentrates on three of the more commonly performed canal procedures: trabeculotomy ab interno (Trabectome), Canaloplasty, and trabeculotomy ab externo.

RECENT FINDINGS

Trabeculotomy ab interno performed with the Trabectome has been shown to lower intraocular pressure (IOP) almost 40% by 12 months with minimal complications. Trabectome alone, as well as combined with cataract surgery, appears to lower IOP quite well. Canaloplasty has also been shown to lower IOP by 38% and combined with cataract surgery, IOP was lowered 44% at 24 months. Trabeculotomy lowers IOP well, especially in older adults. Phacotrabeculotomy lowers IOP to 21 mmHg or less in 84% of patients with supplemental use of medications, and in 36% of patients without at 3 years.

SUMMARY

Canal surgery has proven to be an alternative to traditional glaucoma surgery, lowering IOP relatively well. Surgeons must be comfortable with the anatomy and proceed with the procedure in eyes that are amenable to various new surgical advances.

Nonpenetrating glaucoma surgery

Nonpenetrating glaucoma surgeries have been developed in recent years in order to improve the safety of conventional filtering procedures. The goal of nonpenetrating filtering procedures is to reduce intraocular pressure by enhancing the natural aqueous outflow channels, while reducing outflow resistance located in the inner wall of the Schlemm's canal and the juxtacanalicular trabecular meshwork. In the last few years viscocanalostomy and deep sclerectomy with external trabeculectomy have become the most popular nonpenetrating filtering procedures. Both involve removal of a deep scleral flap, the external wall of Schlemm's canal and corneal stroma behind the anterior trabeculum and Descemet's membrane, thus creating an intrascleral space. The aqueous humour leaves the anterior chamber through the intact trabeculo-Descemet's membrane into the scleral space, from where it will egress into different pathways. The technique is associated with a long learning curve. Published clinical trials comparing nonpenetrating glaucoma surgery to full-thickness trabeculectomy have a consensus on the superior safety profile of nonpenetrating glaucoma surgery but are not in agreement when it comes to efficacy, where conflicting results have been found. This article reviews the nonpenetrating surgical techniques, mechanisms of action, indications, contraindications, complications, and results.

Phacoviscocanalostomy versus cataract surgery only in patients with coexisting normal-tension glaucoma: midterm outcomes

PURPOSE

To compare the midterm efficacy and safety of phacoviscocanalostomy (viscocanalostomy, phacoemulsification, and intraocular lens [IOL] implantation) and cataract surgery (phacoemulsification and IOL implantation) in patients with normal-tension glaucoma (NTG) and cataract.

SETTING

Sensho-kai Eye Institute, Kyoto, Japan.

METHODS

Thirty-one eyes had phacoviscocanalostomy, and 35 eyes had uncomplicated cataract surgery only. The intraocular pressure (IOP), postoperative antiglaucoma medications, and visual outcomes were compared between groups.

RESULTS

The mean follow-up was 34.9 months+/-19.8 (SD) (range 7 to 78 months). At 36 months, the mean preoperative IOP and postoperative IOP were 17.2+/-1.5 mm Hg and 14.1+/-1.6 mm Hg, respectively, in the phacoviscocanalostomy group and 16.7+/-1.4 mm Hg and 15.6+/-3.4 mm Hg, respectively, in the cataract surgery only group. The differences between groups were significant at all time points (P<.05). The success probabilities of the phacoviscocanalostomy group achieving 20% and 30% IOP reductions with (or without) medications were 78.5% (67.4%) and 35.5% (37.4%) at 24 months and 58.0% (44.2%) and 28.0% (26.6%) at 48 months, which were significantly better than the probabilities in the cataract surgery only group, which were 16.0% (9.5%) and 5.7% (2.9%) at 24 months (P<.001 for each comparison, Kaplan-Meier life-table analysis with log-rank test). Based on the modified Aulhorn-Greve classification, the visual acuity and visual fields did not deteriorate in the phacoviscocanalostomy group; the visual fields deteriorated in 6 eyes in the cataract surgery only group during the follow-up (P=.024).

CONCLUSION

Phacoviscocanalostomy lowered IOP and maintained postoperative visual outcomes; it was safe and effective in elderly patients with coexisting NTG and cataract.

Canaloplasty: Circumferential viscodilation and tensioning of Schlemm's canal using a flexible microcatheter for the treatment of open-angle glaucoma in adults

PURPOSE

To evaluate the safety and efficacy of circumferential viscodilation and tensioning of the inner wall of Schlemm's canal in a new surgical procedure for the treatment of open-angle glaucoma (OAG).

SETTING

Fourteen clinical sites in the United States and Germany.

METHODS

In this international multicenter prospective study of adult patients with OAG having glaucoma surgery, patients with qualifying preoperative intraocular pressure (IOP) of at least 16 mm Hg or higher and open angles were eligible. Evaluation was performed at baseline and 1 day, 1 week, and 1, 3, 6, and 12 months preoperatively. After a nonpenetrating dissection technique to expose Schlemm's canal was performed, a flexible microcatheter (iTrack 250A, iScience Interventional) was used to dilate the full circumference of the canal by injecting sodium hyaluronate 1.4% (Healon GV) during catheterization. A suture loop was placed in the canal to apply tension to the trabecular meshwork. High-resolution ultrasound imaging was used to assess Schlemm's canal and anterior segment angle morphology, including distension of the trabecular meshwork caused by the tensioning suture. Data analysis was performed in 2 groups: Group 1, in which patients met all inclusion criteria, and Group 2, made up of Group 1 patients who had successful suture placement.

RESULTS

Group 1 comprised 94 patients and Group 2, 74 patients. The mean baseline IOP in Group 1 was 24.7 mm Hg+/-4.8 (SD) on a mean of 1.9+/-1.0 medications per patient. In Group 2 (patients with sutures), the mean IOP was 16.1+/-4.7 mm Hg 3 months postoperatively, 15.6+/-4.0 mm Hg at 6 months, and 15.3+/-3.8 mm Hg at 1 year. Medication use dropped to a mean of 0.6+/-0.9 per patient at 12 months. Suture tensioning was an apparent contributing factor in achieving surgical success. Patients with measurable trabecular meshwork distension from suture tension had a mean IOP of 15.9+/-5.2 mm Hg at 6 months and 14.5+/-3.0 mm Hg at 12 months. Surgical and postsurgical adverse events were reported in 15 of 94 patients (16%) and included hyphema (3), elevated IOP greater than 30 mm Hg (3), Descemet's tear (1), hypotony (1), choroidal effusion (1), and exposed closure suture with eyelid edema and erythema epiphora (1); 4 patients were subsequently converted to trabeculectomy.

CONCLUSION

Circumferential viscodilation and tensioning of Schlemm's canal was a safe and effective surgical procedure to reduce IOP in adult patients with OAG.

Nonpenetrating glaucoma surgery: a critical evaluation

PURPOSE OF REVIEW

Nonpenetrating glaucoma surgery is popular in a number of countries because of its perceived superior safety profile to mitomycin-C trabeculectomy. This article critically evaluates recently published literature relating to nonpenetrating glaucoma surgery.

RECENT FINDINGS

Recent modifications in nonpenetrating glaucoma surgery, including the use of implants, augmentation with antiproliferatives, and use of laser goniopuncture, appear to result in improved intraocular pressure control. Comparative studies suggest a better safety profile with nonpenetrating glaucoma surgery but higher long-term intraocular pressure than after trabeculectomy. Despite this perception, a difference in intraocular pressure control between mitomycin-C trabeculectomy and nonpenetrating glaucoma surgery, when the most recent modification has been incorporated, has not been demonstrated conclusively in randomized trials conducted over sufficiently long periods to be clinically important.

SUMMARY

Nonpenetrating glaucoma surgery continues to evolve. Intraocular pressure-lowering efficacy seems to have improved with recent modifications in technique but the degree and longevity of intraocular pressure-lowering in comparison with trabeculectomy are still uncertain.

Viscocanalostomy versus trabeculectomy for primary open angle glaucoma: 4-year prospective randomized clinical trial

AIMS

The purpose of this randomized clinical trial was to compare the effectiveness and safety of viscocanalostomy (visco) with trabeculectomy (trab) in the management of primary open angle glaucoma (POAG).

METHODS

Patients were randomized to have a viscocanalostomy (25 eyes) or a trabeculectomy (25 eyes) performed by one surgeon (TDM) and followed up prospectively. Patients were examined preoperatively, at day 1, day 3 if required, day 6, week 2 and thereafter as near as possible to 1, 3, 6, 12, 18, 24, 30, 36, 48, 54, and 60 months. We recorded intraocular pressure (IOP), presence or absence of any complications, presence and description of any bleb, visual acuity with glasses, and full examinations as routine to monitor any progression of the glaucoma. Bleb interventions including needling and antimetabolites were allowed and recorded in both groups. YAG laser goniopuncture was allowed in the viscocanalostomy group.

RESULTS

Mean follow-up was 40 months (SD 15), with a range from 6 to 60 months. Forty-two percent (n=10) of the patients in the trabeculectomy group had a successful outcome (IOP<18 mm Hg with no treatment) at last follow-up visit, compared to 21% (n=5) in the viscocanalostomy group. IOP was lower in the trab group with differences in IOP being statistically significant at month 12 (P=<0.001), 24 (P=<0.001), 30 (P=0.030), 36 (P=<0.001), and 48 (P=0.018). The trabeculectomy group required less postoperative topical IOP-lowering medication (P=0.011).

CONCLUSION

In this study, we found trabeculectomy to be more effective at lowering IOP than viscocanalostomy in POAG patients.

Seven-year follow-up of combined cataract extraction and viscocanalostomy

PURPOSE

To investigate the long-term success and complications of phacoemulsification combined with viscocanalostomy (phacoviscocanalostomy) in eyes with coexisting cataract and medically uncontrolled glaucoma.

SETTING

Department of Ophthalmology, Warrington Hospital, Warrington, United Kingdom.

METHODS

A prospective nonrandomized study evaluated 165 consecutive eyes (114 patients) that had phacoviscocanalostomy. The main outcome measures were intraocular pressure (IOP), visual acuity, requirement for topical antiglaucoma medication, and the presence or absence of drainage blebs or bleb complications.

RESULTS

The mean follow-up was 38.7 months +/- 19.3 (SD) (range 12 to 90 months). There was a statistically significant decrease in IOP, from 24.1 +/- 5.1 mm Hg preoperatively to 13.8 +/- 8.1 mm Hg 1 day after surgery (P<.001), 16.0 +/- 4.1 mm Hg at 5 years (P<.001), and at all evaluations to the last follow-up. The mean number of medications per eye decreased significantly from 2.5 +/- 0.9 before surgery to 0.1 +/- 0.5 at last follow-up (P<.001). At the final follow-up, IOP was reduced by 33.2% (16.2 mm Hg versus 24.1 mm Hg). Complete success, defined as an IOP reduction of more than 30% from preoperative level without medications, was achieved in 48.5% of eyes, with 42% of eyes having an IOP of less than 16 mm Hg. The percentage fall in IOP was linearly related to the preoperative IOP level (P<.001). No eye developed a trabeculectomy-type bleb, and there were no bleb-related complications.

CONCLUSIONS

Phacoviscocanalostomy was safe and effective for the management of eyes with coexisting cataract and medically uncontrolled glaucoma. It provided a stable and sustained reduction in IOP with a minimum requirement for topical medication.

Long-term results of Erbium YAG-laser-assisted deep sclerectomy

PURPOSE

To evaluate the long-term results of Erbium YAG-laser-assisted deep sclerectomy (DS). In this procedure, the delicate dissection of a deep corneoscleral lamella is greatly simplified by using the Erbium YAG-laser.

METHODS

Data of 14 consecutive patients (10 male, four female, age 67.7+/-10.4 years), who underwent surgery from 1999 to 2000 were analysed retrospectively. The procedure was begun as a standard DS. The deep corneoscleral lamella was dissected with a pulsed Erbium YAG-laser (energy: 40-100 mJ, frequency: 5-10 Hz). Schlemm's canal was unroofed and the lamella thinned until aqueous percolated continuously through the membrane.

RESULTS

The mean follow-up time was 50.4+/-6.8 months. The mean preoperative intraocular pressure (IOP) was 37.7+/-10.5 mmHg. The mean postoperative IOP was 16.1+/-3.9 mmHg at 1 month, 15.1+/-4.3 mmHg at 3 months, 16.4+/-4.5 mmHg at 12 months, and 17.6+/-8.7 mmHg at 50.5 months. The complete success rates (IOP< or =21 mmHg+IOP reduction > or =20% without glaucoma medication) were 83.3% at 3 months and 50% at 12 and 50.5 months. Rates for qualified success (IOP< or =21 mmHg+IOP reduction > or =20% with glaucoma medication) were 91.7% at 3 months, 92.9% at 12 months, and 78.6% at 50.5 months. The number of glaucoma medications was reduced from 3.07+/-0.92 preoperatively to 1.14+/-1.41 at 50.5 months. A single case of anterior-chamber penetration, requiring iridectomy, was the only intraoperative complication.

CONCLUSIONS

Erbium YAG-laser-assisted DS has the advantage of a greatly simplified dissection, while offering a successful long-term IOP control comparable to conventional DS.

Trabeculectomy with brief exposure to mitomycin C

BACKGROUND

To evaluate the safety and efficacy of primary trabeculectomy with brief exposure (15 s) to mitomycin C (MMC) (0.4 mg/mL).

METHODS

Medical record review of all patients who underwent primary trabeculectomy with brief exposure to MMC at the Goldschleger Eye Institute in a 4-year period was performed.

RESULTS

Sixty-three patients (35 men, mean age of 55 years) underwent trabeculectomy with brief exposure to MMC. Intraocular pressure (IOP) decreased a mean +/- standard deviation of 17.9 +/- 9.6 mmHg from 30.4 +/- 9.5 mmHg preoperatively to 12.5 +/- 6.2 mmHg postoperatively after a mean follow up of 18.3 months (P < 0.001). Number of antiglaucoma medications decreased from 2.9 +/- 1.1 preoperatively to 0.2 +/- 0.4 postoperatively (P < 0.001, paired samples t-test). Complete success, defined as IOP < 18 mmHg without antiglaucoma medication, was achieved in 46 patients (73%) and qualified success, defined as IOP <or= 21 mmHg with or without antiglaucoma medications, was achieved in 59 patients (93.7%). Thirty-eight patients (60%) had a final IOP < 15 mmHg with no glaucoma medications at the end of follow up. Needle revision was required in four patients (6.3%) and repeated trabeculectomy was performed in three patients (4.8%). Four patients had an IOP of less than 6 mmHg at the end of follow-up period (three had final IOP of 5 mmHg and one of 4 mmHg); these patients had an average larger bleb size (2.8 +/- 1.3).

CONCLUSIONS

Trabeculectomy with brief (15 s) exposure to MMC 0.4 mg/mL is safe and effective in lowering IOP in this group of patients, and results in low rate of postoperative complications. Success is comparable to reported data with longer exposure durations to antimetabolites.

Do scleral flap dimensions influence reliability of intraocular pressure control in experimental trabeculectomy?

AIM

To compare the effect on intraocular pressure (IOP) of large vs small scleral flap size during trabeculectomy using adjustable sutures.

METHODS

Trabeculectomy operations were performed on nine donor human eyes connected to a constant flow infusion with real-time IOP monitoring. Large scleral flaps (4 x 4 mm, 16 mm(2), n=12) or small scleral flaps (3 x 2 mm, 6 mm(2), n=9) were constructed over 0.76 mm(2) sclerostomies. For each procedure, equilibrium IOP was measured following tight closure with two four-throw adjustable 10-0 nylon sutures.

RESULTS

Five scleral flaps were thin or poorly constructed; four of these were in the initial seven procedures, implying learning effect. These had a mean absolute IOP of 7.6 mmHg (range 2.7-12.4 mmHg) and mean relative IOP of 28.3% of baseline (range 10-45.8%) after closure. In the remaining 16 good quality procedures, mean IOP was 1.3 mmHg (range 0-3.4 mmHg) after sclerostomy, confirming minimal outflow resistance before closure. Following flap closure mean IOP was 20 mmHg (SD 4.4, range 15.5-29.3 mmHg) for large (n=8), and 18.7 mmHg (SD 3.6, 15.9-25.8 mmHg) for small (n=8) flaps (unpaired t-test, P=0.26). Mean IOP (% baseline) was 71.6% (SD 8.4, range 60.6-86.6%) and 66% (SD=12.7, 46.8-86.6%) for large and small flap groups, respectively (unpaired t-test, P=0.2).

CONCLUSIONS

Well-constructed scleral flaps of both sizes were able to support an average IOP at least two-thirds of baseline, and both had similar absolute IOP levels. Errors in flap construction resulted in loss of IOP control. Smaller flap size does not appear to compromise control of early postoperative IOP using adjustable sutures.

Control of intraocular pressure after deep sclerectomy

AIM

To study the long-term outcome of deep sclerectomy in patients with open angle glaucoma.

METHODS

Prospective consecutive series of 43 eyes (38 patients) with medically uncontrolled open-angle glaucoma undergoing deep sclerectomy. All patients underwent clinical assessment before and after surgery at day 7 and at months 1, 3, 6, 12, 18, 24, 36. Surgical success was considered if the patient's intraocular pressure (IOP) < 22 mmHg and the IOP was lowered by more than 20% without the use of any medication. Kaplan-Meier survival curves were used to evaluate the success rate.

RESULTS

The mean follow-up time was 28.1 +/- 8.2 months. Mean IOP decreased significantly from a preoperative value of 24.6 +/- 5.5 mmHg to a postoperative value of 18.5 +/- 4.6 mmHg at 36 months (P < 0.001). Microperforation of TDM occurred in three cases (7.0%) and ciliary body prolapse in one case (2.3%) but did not prevent completion of the operation. Postoperatively, hyphaema was detected in one case and shallow anterior chamber in another case and both were treated conservatively. Bleb encapsulation with elevation of IOP occurred in two cases (4.7%) and was treated with 5-fluorouracil subconjunctival injection. Goniopuncture with neodymium : YAG laser was performed in two cases (4.7%). There were no other late complications with the exception of failure of the operation. On the life-table analysis the success rate at 12, 24, and 30 months were 61.4, 36.6, and 18.9%, respectively.

CONCLUSION

Deep sclerectomy reduced the IOP temporarily while minimising the risk of postoperative complications commonly encountered with standard trabeculectomy. However, after long-term follow-up surgery failed to maintain a low IOP.