Assessment of the Incorporation of Patient-Centric Outcomes in Studies of Minimally Invasive Glaucoma Surgical Devices

The case for standalone micro-invasive glaucoma surgery: rethinking the role of surgery in the glaucoma treatment paradigm

PURPOSE OF REVIEW

To highlight progress in glaucoma therapy challenging the traditional medication-first approach and present evidence supporting early standalone surgery in the era of micro-invasive glaucoma surgery (MIGS).

RECENT FINDINGS

Medical therapy is limited by well documented poor adherence that compromises the quality of intraocular pressure reduction. Results from modern clinical trials demonstrate advantages of selective laser trabeculoplasty and MIGS procedures in terms of both IOP control and progression risk.

SUMMARY

The MIGS options for pseudophakic or precataractous patients are limited by regulatory rules that require the performance of some procedures only at the time of cataract surgery. These include the iStent/iStent Inject and the Hydrus implants. Nonbleb-forming procedures currently available for standalone use in eyes with mild-moderate primary open-angle glaucoma include gonioscopy-assisted transluminal trabeculotomy (which lowers IOP by 28-61% and medication use by 38-73% in various studies), trabecular ablation with the Trabectome (23-39% and 21-43%, respectively), excisional goniotomy with the Kahook Dual Blade (15-36% and 15-40%, respectively), ab interno canaloplasty (35% and 57%, respectively), and combined canaloplasty and trabeculotomy using the OMNI system (39-40% and 64-73%, respectively). For patients who would benefit from early standalone surgery, these procedures offer meaningful reductions in both IOP and medication burden.

Impact of minimally invasive glaucoma surgery on the ocular surface and quality of life in patients with glaucoma

Background:

Minimally invasive glaucoma procedures are emerging as clinically effective and safe glaucoma management approaches; however, evidence regarding quality-of-life outcomes is limited.

Objectives:

To explore the impact of minimally invasive glaucoma surgery (MIGS) combined with phacoemulsification on patient-reported outcomes and clinical parameters related to ocular surface disease in people with glaucoma.

Design:

Retrospective observational study.

Methods:

Fifty-seven consecutive patients were examined prior to undergoing iStent combined with phacoemulsification with or without adjunctive endocyclophotocoagulation and at 4-month follow-up.

Results:

At follow-up, on average patients returned statistically significantly improved scores on glaucoma-specific (GQL-15, p < 0.001; GSS, p < 0.001), general health (EQ-5D, p = 0.02) and ocular surface PROMs (OSDI, p = 0.001). Patients were using fewer eye drops on average after MIGS compared with before surgery (1.1 ± 0.9 versus 1.8 ± 0.8; p < 0.001). Undergoing MIGS was associated with improved tear film break-up time ( p < 0.001) and reduced corneal fluorescein staining ( p < 0.001).

Conclusion:

This retrospective audit shows quality of life and clinical parameters related to the ocular surface are improved following MIGS combined with phacoemulsification in patients previously treated with anti-glaucoma therapy.

Priorities and Treatment Preferences among Surgery-Naive Patients with Moderate to Severe Open-Angle Glaucoma

PURPOSE

To explore patients' perspectives and experiences living with moderate to severe glaucoma through qualitative, semistructured interviews and to identify important benefits and risks that patients consider when choosing glaucoma treatments.

DESIGN

Semistructured, in-person qualitative interviews with a convenience sample of patients seen at the Johns Hopkins Wilmer Eye Institute.

PARTICIPANTS

Surgery-naive patients 21 years of age or older with moderate to severe open-angle glaucoma seeking treatment at the Wilmer Eye Institute's Glaucoma Center of Excellence between August and December 2018.

METHODS

We conducted semistructured interviews with patients diagnosed with moderate to severe open-angle glaucoma, focusing on outcomes they prioritize when considering various treatment options. We used Atlas.ti software version 7.5.12 (Scientific Software Development GmbH, Berlin, Germany) to process interview transcripts and the framework approach to analyze the qualitative data.

MAIN OUTCOME MEASURES

Patients' descriptions of outcomes important to them in management of moderate to severe open-angle glaucoma.

RESULTS

Thirteen men and 15 women with a median age 67 years participated in the study. Compared with the mild-to-moderate glaucoma patients interviewed previously, these participants similarly emphasized (1) activities of daily living, (2) visual symptoms, (3) treatment burden, and (4) intraocular pressure (IOP) control, but unlike patients with milder disease, most related IOP control directly to (5) avoiding disease progression. Almost all (27/28) had also given significant thought to (6) surgical decision making and could describe how they would decide for or against a particular procedure. Finally, two thirds (18/28) expressed (7) significant fear and worry related to their glaucoma diagnosis.

CONCLUSIONS

We identified outcomes that matter to patients who are undergoing treatment for moderate to severe glaucoma, many of which may serve as end points in clinical trials, such as functional independence in vision-dependent activities of daily living, avoidance of visual symptoms, and disease progression via maintenance of IOP control. We also observed that these patients have varied and nuanced perspectives on surgical management and its outcomes. It behooves providers and trial designers to consider these in future evaluations of new treatments for moderate to severe glaucoma.

Patient-reported outcomes measures and patient preferences for minimally invasive glaucoma surgical devices

BACKGROUND

Many therapeutic options are available to glaucoma patients. One recent therapeutic option is minimally invasive glaucoma surgical (MIGS) devices. It is unclear how patients view different treatments and which patient-reported outcomes would be most relevant in patients with mild to moderate glaucoma. We developed a questionnaire for patients eligible for MIGS devices and a patient preference study to examine the value patients place on certain outcomes associated with glaucoma and its therapies.

OBJECTIVES

To summarize the progress to date.

METHODS

Questionnaire development: We drafted the questionnaire items based on input from one physician and four patient focus groups, and a review of the literature. We tested item clarity with six cognitive interviews. These items were further refined. Patient preference study: We identified important benefit and risk outcomes qualitatively using semi-structured, one-on-one interviews with patients who were eligible for MIGS devices. We then prioritized these outcomes quantitatively using best-worst scaling methods.

RESULTS

Questionnaire testing: Three concepts were deemed relevant for the questionnaire: functional limitations, symptoms, and psychosocial factors. We will evaluate the reliability and validity of the 52-item draft questionnaire in an upcoming field test. Patient preference study: We identified 13 outcomes that participants perceived as important. Outcomes with the largest relative importance weights were "adequate IOP control" and "drive a car during the day."

CONCLUSIONS

Patients have the potential to steer clinical research towards outcomes that are important to them. Incorporating patients' perspectives into the MIGS device development and evaluation process may expedite innovation and availability of these devices.

Prioritizing outcome preferences in patients with ocular hypertension and open-angle glaucoma using best-worst scaling

Purpose

To quantify patients' preferences for glaucoma outcomes and use this information to prioritize outcomes that are important to patients.

Design

A cross-sectional study using best-worst scaling object case (BWS).

Participants

Two hundred seventy-four participants newly diagnosed with ocular hypertension or mild to moderate open angle glaucoma from three private practices and one academic medical center in the United States.

Methods

We designed a preference-elicitation survey based on findings from 25 semi-structured, qualitative interviews with patients with glaucoma (reported elsewhere). The survey asked participants to rate the importance of 13 glaucoma outcomes on a Likert scale as a warm-up exercise followed by completion of 13 BWS tasks. For each task, we presented participants a subset of four outcomes from the possible thirteen, and participants chose the most important and least important outcome. Outcomes included in the survey pertain to maintaining ability to perform vision-dependent activities of daily living (e.g., driving), maintaining visual function and perception (e.g., depth perception), minimizing need to take glaucoma drops, not experiencing ocular surface symptoms (e.g., red eyes, teary eyes), and having adequate control of intraocular pressure (IOP). We administered the survey online and analyzed response patterns using conditional logistic regression to determine the relative importance of different outcomes.

Main outcome

Ordinal ranking of glaucoma outcomes based on preference weights.

Results

Between September 1, 2017 and February 28, 2018, we invited 1035 patients to complete our survey, among whom 274 (26%) responded. Most participants were older than 65 years of age (146/274, 53%) and currently on IOP-lowering drops (179/274, 65%). Participants identified that outcomes with the largest relative importance weight were having "adequate IOP control" and ability to "drive a car during the day," and the outcomes with the smallest relative importance weights were "maintaining appearance of the eye" and "reducing the number of IOP-lowering drops".

Conclusions

Determining the relative importance of glaucoma outcomes to patients can help researchers design studies that may better inform clinical and regulatory decision-making. Although IOP is an outcome that researchers often measure in glaucoma clinical trials, patients also prioritized outcomes related to the ability to perform vision-dependent activities such as driving.

Identifying outcomes that are important to patients with ocular hypertension or primary open-angle glaucoma: a qualitative interview study

Purpose

To explore patients' perspectives and experiences living with glaucoma and identify important benefits and risks that patients consider before electing for new glaucoma treatments, such as minimally invasive glaucoma surgical (MIGS) devices.

Design

Semi-structured, in-person qualitative interviews with patients seen at the Johns Hopkins Wilmer Eye Institute.

Participants

Adults older than 21 years of age who were suspected or diagnosed with ocular hypertension or mild to moderate primary open-angle glaucoma (POAG) (and thus eligible for treatment with a MIGS procedure) presenting to a glaucoma clinic in Baltimore, Maryland, between May and December 2016.

Method

We conducted in-person interviews with patients recently diagnosed with ocular hypertension or POAG. We focused on considerations patients take into account when deciding between different treatments. We used the framework approach to code and analyze the qualitative data. Considerations of special interest to us were those that can be translated into outcomes (or endpoints) in clinical trials.

Main outcome measures

Patients' perspectives concerning outcomes that matter to them when managing ocular hypertension or POAG.

Results

Ten male and fifteen female patients participated in our study. The median participant age was 69 years (range 47 - 82 years). We identified outcomes that patients expressed as important, which we grouped into four thematic categories: (1) limitations in performing specific vision-dependent activities of daily living; (2) problems with general visual function or perceptions; (3) treatment burden, including ocular adverse events; and (4) intraocular pressure (IOP). All 25 participants expressed some concerns with their ability to perform vision-dependent activities, such as reading and driving. Most (23/25) participants had an opinion about IOP, and among those currently taking ocular hypotensive eye drops, all recognized the relationship between eye drops and IOP.

Conclusion

We have identified outcomes that matter to patients who are deciding between different treatments for ocular hypertension and POAG, such as the ability to drive or maintain mobility outside the home. These outcomes will be important in future evaluations of new treatments for glaucoma.

Research Questions and Outcomes Prioritized by Patients With Dry Eye

Importance

Dry eye is a common ocular surface condition with significant influence on patient quality of life and societal economic burden. There is an urgent need to prioritize new research for dry eye.

Objective

To identify and rank research questions and outcomes important to patients with dry eye.

Design, Setting, and Participants

This study was conducted using the following 6 steps: (1) identifying research questions from a previous survey of clinicians who treat patients with dry eye; (2) identifying outcomes from existing research (systematic reviews and their cited clinical trials in the Cochrane Eyes and Vision US Satellite database of eyes and vision reviews, and National Eye Institute-funded clinical trials registered on ClinicalTrials.gov) as of June 13, 2017; (3) identifying a sample of patients with dry eye from the email subscribers to the online newsletter KeratoScoop; (4) and (5) conducting a 2-round Delphi survey of those patients online in November and December 2017, respectively; and (6) designating and ranking questions and outcomes as important.

Main Outcomes and Measures

Importance assigned to research questions and outcomes for dry eye. A research question or outcome ranked by at least 75% of patients as 6 or higher on a scale of 0 to 10 was considered important.

Results

Among the 420 patients from 15 countries who completed both rounds of the Delphi survey, most were 60 years of age or older (233 [56%]), female (348 [83%]), white (393 [94%]), and of non-Hispanic ethnicity (398 [95%]). Among the 12 questions that clinicians had previously prioritized, patients rated 8 as important. The top 3 questions pertained to effectiveness of patient education, environmental modifications, and topical anti-inflammatory eye drops for dry eye. Among the 109 outcomes identified in existing research on dry eye, patients rated 26 as important. Ten of these 26 were unpopular in existing research, with fewer than 10% of 158 studies reporting these outcomes. Of the 10 most important outcomes, 9 were associated with symptoms or quality of life. The 3 outcomes rated most important by patients were ocular burning or stinging, ocular discomfort, and ocular pain.

Conclusions and Relevance

This study identified research questions and outcomes important to patients with dry eye. A considerable gap was noted between outcomes in existing research on dry eye and outcomes patients consider important. Future research on dry eye should consider addressing the important research questions and outcomes identified herein, taking into account the patient perspective.

The long-term outcome of trabeculotomy: comparison with filtering surgery in Japan

Background

To investigate the long-term outcome of trabeculotomy and to compare it with that of trabeculectomy.

Methods

We retrospectively reviewed the medical records of patients who had undergone standalone trabeculotomy. Inclusion criteria included a follow-up period of at least 6 years, availability of reliable static visual field results, etc. Age- and preoperative intraocular pressure -matched trabeculectomy cases served as controls. A Kaplan-Meier analysis was employed as a measure of surgical success. Additional clinical factors were also analyzed.

Results

Twenty-five eyes of 25 trabeculotomy patients and 20 eyes of 20 trabeculectomy patients with a mean postoperative follow-up period of 8.0 years were selected. The Kaplan-Meier analysis estimated that the success probability defined as intraocular pressure < 16 mmHg was 44.0 ± 9.9% and 75.0 ± 9.7% at 6 years for trabeculotomy and trabeculectomy, respectively. The final mean deviation significantly progressed in trabeculotomy cases in Central 30–2 programs of the Humphrey Field Analyzer (P = 0.025). Patient characteristics and postoperative clinical data were analyzed by Mann-Whitney’s U test and Wilcoxon signed-rank test.

Conclusions

While trabeculotomy was inferior to trabeculectomy in terms of intraocular pressure control and visual field stability in our series, surgical indications should always be determined on an individual basis, pending further research.

Ab interno trabecular bypass surgery with iStent for open-angle glaucoma

BACKGROUND

Glaucoma is a leading cause of irreversible blindness worldwide. In early stages, glaucoma results in progressive loss of peripheral (side) vision; in later stages, it results in loss of central vision leading to blindness. Elevated intraocular pressure (IOP) is the only known modifiable risk factor for glaucoma. Minimally invasive glaucoma surgical (MIGS) techniques, such as ab interno trabecular bypass surgery with iStent (Glaukos Corporation, Laguna Hills, CA, USA), have been introduced as a new treatment modality for glaucoma. However, the effectiveness of MIGS on keeping people 'drop-free' (i.e. not having to use eye drops to control IOP) and other outcomes is uncertain.

OBJECTIVES

To assess the effectiveness and safety of ab interno trabecular bypass surgery with iStent (or iStent inject) for open-angle glaucoma in comparison to conventional medical, laser, or surgical treatment.

SEARCH METHODS

Cochrane Eyes and Vision's Information Specialist searched the following databases on 17 August 2018: the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register; 2018, Issue 7), MEDLINE Ovid, Embase Ovid, the ISRCTN registry, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We applied no date or language restrictions. We searched the reference lists of reports from included studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that had compared iStent or iStent inject to medical therapy, laser treatment, conventional glaucoma surgery (trabeculectomy), or other MIGS procedures. We included RCTs that had compared iStent or iStent inject in combination with phacoemulsification to phacoemulsification alone.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently screened search results, assessed risk of bias, and extracted data from reports of included RCTs using an electronic data collection form.

MAIN RESULTS

We included seven RCTs (765 eyes of 764 participants; range per study 33 to 239 participants) that evaluated iStent in people with open-angle glaucoma. We also identified 13 studies that are ongoing or awaiting publications of results. Most participants in the included studies were women (417/764 (55%) participants) and older age (age range: 49 to 89 years). We assessed most trials at unclear or high risk of bias: four trials did not clearly report the method of generating the random sequence or concealing allocation; five were unmasked, open-label studies, which we assessed at high risk of bias for performance and detection bias. All seven trials were funded by the Glaukos Corporation. We graded the certainty of evidence as very low.Four RCTs compared iStent in combination with phacoemulsification to phacoemulsification alone. The summary estimate which we derived from two of the four RCTs suggested that participants in the iStent in combination with phacoemulsification group were 1.38 times more likely to be drop-free between six and 18 months than those in the phacoemulsification alone group (risk ratio (RR) 1.38, 95% confidence interval (CI) 1.18 to 1.63, I² = 67%). Data from two RCTs also suggested that iStent in combination with phacoemulsification compared to phacoemulsification alone may have offered a small reduction in number of IOP-lowering drops (mean difference (MD) -0.42 drops, 95% CI -0.60 to -0.23). It is uncertain whether there was any difference in terms of mean reduction in IOP from baseline (no meta-analysis).Two RCTs compared treatment with iStent to medical therapy; one of the two trials used the iStent inject. We determined the two trials to be clinically and methodologically heterogeneous and did not conduct a meta-analysis; however, the investigators of both trials reported that over 90% of participants in the treatment groups were drop-free compared to no participants in the medical therapy groups at six to 18 months.One RCT compared treatment with one versus two versus three iStents. There was no difference in terms of participants who were drop-free at 36 months or less; however, at longer follow-up (i.e. at 42 months) participants in the one iStent treatment were less likely to be drop-free than those in the two iStent (RR 0.51, 95% CI 0.34 to 0.75) or three iStent (RR 0.49, 95% CI 0.34 to 0.73) treatment groups. The study did not report the mean change in number of IOP-lowering drops.The type and timing of complications reported varied by RCTs. Similar proportions of participants who underwent treatment with iStent in combination with phacoemulsification and who underwent phacoemulsification alone needed secondary glaucoma surgery. None of RCTs reported findings related to quality of life.

AUTHORS' CONCLUSIONS

There is very low-quality evidence that treatment with iStent may result in higher proportions of participants who are drop-free or achieving better IOP control, in the short, medium, or long-term. Results from the 13 studies with results not yet available may clarify the benefits of treatment of people with iStent. Additionally, future MIGS studies should consider measuring quality of life and outcomes that reflect people's ability to perform vision-dependent activities.

Ophthalmic Drug Discovery and Development: Regulatory Aspects of Patient Focused Drug Development in Ophthalmology

In 2009, members of the ophthalmic research community held a joint meeting with members of the Food and Drug Administration (FDA) and the National Eye Institute (NEI) to define and describe the types of patient-focused drug development (PFDD) tools used in ophthalmology. Since then numerous reports have been published which indicate that many of the questionnaires used for patient-reported outcomes (PROs) in ophthalmic clinical development lack rigor and reliability according to modern methods. In 2017, the FDA began development of a series of four methodological guidances for sponsors of clinical trials on the significance of PFDD. The new guidances delineate the FDA's thinking and commitments under the Prescription Drug User Fee Act to implement a more structured approach to the assessment of risks and benefits in clinical trials. In these guidances, the FDA provides steps that drug and device manufacturers should follow, not only to obtain, but also to develop reliable and validated tools that measure patients' experience in clinical trials. Subsequent efforts have resulted in the development and validation of PROs specifically for ophthalmology. The purpose of this paper is to assesses the PROs currently used in ophthalmology and to provide practical strategies for incorporating them into clinical trials.

Cochrane Eyes and Vision: a perspective introducing Cochrane Corner in Eye

In 1972, Archie Cochrane wrote "It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials". The Cochrane Collaboration arose in response to Archie Cochrane's challenge. Cochrane Eyes and Vision aims to prepare and promote access to systematic reviews of interventions for preventing or treating eye conditions and/or visual impairment, and helping people adjust to visual impairment or blindness. To identify all relevant randomised controlled trials, Cochrane Eyes and Vision has a team of information specialists who develop search strategies to identify studies for inclusion in Cochrane reviews. Since 1997 we have published 266 protocols, 193 new reviews and 158 updated reviews. The majority of these are reviews of intervention effectiveness; three reviews are diagnostic test accuracy reviews. Overall 18% of reviews contain no trials, highlighting a potential evidence gap. We provide training, education and guidance to systematic review authors and work with clinical and patient partners to prioritise and disseminate reviews. In addition, Cochrane Eyes and Vision US satellite carries out critical methodologic research addressing topics relevant to producing high-quality reviews. We are partnering with the journal Eye to publish commentaries on selected Cochrane systematic review findings. This partnership will allow us to make high-quality evidence available to ophthalmologists and other practitioners, researchers, policy makers and patients.

The use of patient-reported outcome research in modern ophthalmology: impact on clinical trials and routine clinical practice

This review article considers the rising demand for patient-reported outcome measures (PROMs) in modern ophthalmic research and clinical practice. We review what PROMs are, how they are developed and chosen for use, and how their quality can be critically appraised. We outline the progress made to develop PROMs in each clinical subspecialty. We highlight recent examples of the use of PROMs as secondary outcome measures in randomized controlled clinical trials and consider the impact they have had. With increasing interest in using PROMs as primary outcome measures, particularly where interventions have been found to be of equivalent efficacy by traditional outcome metrics, we highlight the importance of instrument precision in permitting smaller sample sizes to be recruited. Our review finds that while there has been considerable progress in PROM development, particularly in cataract, glaucoma, medical retina, and low vision, there is a paucity of useful tools for less common ophthalmic conditions. Development and validation of item banks, administered using computer adaptive testing, has been proposed as a solution to overcome many of the traditional limitations of PROMs, but further work will be needed to examine their acceptability to patients, clinicians, and investigators.

Setting Priorities for Diabetic Retinopathy Clinical Research and Identifying Evidence Gaps

PURPOSE

Prioritizing comparative effectiveness research may contribute to obtaining answers that clinicians perceive they need and may minimize research that could be considered wasteful. Our objective was to identify evidence gaps and set priorities for new systematic reviews and randomized controlled trials for managing diabetic retinopathy (DR), including diabetic macular edema (DME).

DESIGN

Cross-sectional study.

PARTICIPANTS

Diabetic Retinopathy Clinical Research Network (DRCR.net) investigators.

METHODS

We provided recommendations from the American Academy of Ophthalmology's 2012 Preferred Practice Patterns for Diabetic Retinopathy as 91 answerable clinical research questions about intervention effectiveness to 410 DRCR.net investigators to rate each question's importance from 0 (not important) to 10 (very important) using a 2-round Delphi survey and to suggest additional questions. We considered questions as high priority if at least 75% of respondents to both rounds assigned an importance rating of 5 or more in round 2. We also extracted outcome measures relevant to DR and asked respondents to identify those that must be measured in all studies. We mapped Cochrane reviews published up to March 2016 to high-priority clinical research questions.

MAIN OUTCOME MEASURE

Ranking of importance of each clinical question.

RESULTS

Thirty-two individuals completed rounds 1 and 2 and suggested 15 questions. Among the final list of 106 clinical research questions, 22 questions met our definition of high priority: 9 of 22 concerned the effectiveness of anti-VEGF therapy, and 13 of 22 focused on how often patients should be followed up (re-examination) and treatment effectiveness in patients with specific characteristics (e.g., DME). Outcomes that 75% or more of respondents marked as "must be measured in all studies" included visual acuity and visual loss, death of participants, and intraocular pressure. Only 1 prioritized question was associated with conclusive evidence from a Cochrane systematic review.

CONCLUSIONS

A limited response rate among DRCR.net members identified 22 comparative effectiveness research questions as high priority for the management of DR, including DME, but few were associated with Cochrane reviews. These results support the need of systematic reviews and randomized controlled trials to address evidence gaps.

Ab interno trabecular bypass surgery with Trabectome for open angle glaucoma

BACKGROUND

Glaucoma is the leading cause of irreversible blindness. Minimally invasive surgical techniques, such as ab interno trabecular bypass surgery, have been introduced to prevent glaucoma progressing.

OBJECTIVES

The main objective was to assess the results at two years of ab interno trabecular bypass surgery with Trabectome for open angle glaucoma in comparison to conventional medical, laser, or surgical treatment in terms of efficacy and safety. A secondary objective was to examine the effects of Trabectome surgery in people who have concomitant phacoemulsification in comparison to those who do not have concomitant phacoemulsification.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 12 May 2016.

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) of ab interno trabecular bypass surgery with Trabectome.

DATA COLLECTION AND ANALYSIS

We planned to have two review authors independently extract data from reports of included studies using a data collection form.

MAIN RESULTS

One randomised controlled trial identified from ClinicalTrials.gov, NCT00901108, met the criteria for inclusion. This study has subsequently been terminated. The ClinicalTrials.gov record indicates that the investigators plan to complete 12 months of follow-up and analysis on 19 participants already recruited into the trial.

AUTHORS' CONCLUSIONS

There is currently no high-quality evidence for the outcomes of ab interno trabecular bypass surgery with Trabectome for open angle glaucoma. Properly designed RCTs are needed to assess the long-term efficacy and safety of this technique.