Methodological quality of the review: High confidence

Authors: King A, Shah A, Nikita E, Hu K, Mulvaney CA, Stead R, Azuara-Blanco A

Region: Not applicable

Sector: Glaucoma

Sub-sector: Treatment

Equity focus: None specified

Review type: Other review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background:

Glaucoma is a leading cause of irreversible blindness. Subconjunctival draining minimally-invasive glaucoma devices such as the Xen gelatin implant and InnFocus stent have been introduced as a treatment to prevent glaucoma progressing.

These implants provide a channel to allow aqueous humour from the anterior chamber of the eye to drain into the subconjunctival space on the surface of the eye thus reducing intraocular pressure (IOP) and mimicking the mechanism of the most commonly undertaken glaucoma surgery, trabeculectomy.

Objectives:

To evaluate the efficacy and safety of subconjunctival draining minimally-invasive glaucoma devices in treating people with open angle glaucoma and ocular hypertension whose condition is inadequately controlled with drops.

Main findings:

Authors found no completed randomized controlled trials (RCTs) that met their inclusion criteria. They found one ongoing study which compares InnFocus MicroShunt to trabeculectomy in people with primary open-angle glaucoma (POAG). The primary outcome is greater than 20% IOP reduction from baseline to 12 months’ follow-up. A total of 889 people aged between 40 and 85 years have been enrolled. The estimated study completion date is November 2019.

Methodology: 

The authors searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2018, Issue 6); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov and theWHO ICTRP. The date of the search was 10 July 2018.

The authors searched for randomized controlled trials (RCTs) of Xen gelatin implant or InnFocus MicroShunt to other surgical treatments (other minimally-invasive glaucoma device techniques, trabeculectomy), laser treatment or medical treatment. They also planned to include trials where these devices were combined with phaecoemulsification compared to phaecoemulsification alone.

The authors planned to have two review authors independently extract data from reports of included studies using a data collection form and analyze data based on methods expected by Cochrane. Their primary outcome was mean change in IOP. Secondary outcomes included the proportion of participants who were drop-free; the proportion of participants who achieved an IOP of 21 mmHg or less, 17 mmHg or less or 14 mmHg or less; and the proportion of participants experiencing intra- and postoperative complications. It was planned to measure all outcomes in the short-term (six to 18 months), medium-term (18 to 36 months), and long-term (36 months onwards).

Applicability/external validity:

No studies included in the review

Geographic focus

No studies included in the review

Summary of quality assessment:

High confidence was attributed in the conclusions about the effects of this study. Although no studies met the inclusion criteria, a thorough search of the literature was conducted to ensure that all relevant studies were identified in the review.