Glaucoma is the leading cause of blindness worldwide and its primary treatment involves the reduction of intraocular pressure (IOP). The traditional treatment algorithm for primary open angle glaucoma (POAG) consists of topical antiglaucoma medications, laser treatment, and penetrating filtration surgeries, such as trabeculectomy, when IOP is no longer controlled with topical therapy. Poor patient compliance and intolerance to medication are common, while filtering surgeries, which are clinically effective for managing glaucoma, are associated with a high rate of complications including hypotony, failure, and bleb-related infections.

Over the last decade, minimally invasive glaucoma surgery (MIGS) has been developed to fill the treatment gap between topical therapy and invasive glaucoma surgery. In comparison to filtration surgery, MIGS provides several advantages, such as minimal disruption to the eye’s anatomy and physiology and is therefore associated with an improved safety profile and rapid post-surgical recovery. However, not all MIGS procedures are created equally and can be categorized according to the tissue they target: trabecular meshwork (TM) MIGS, subconjunctival MIGS, suprachoroidal MIGS, and cycloablation procedures. Some are focal in approach and work by removing or overcoming outflow resistance in a section of the ocular outflow pathway by bypassing with the use of a stent or removing the trabecular meshwork (TM). Other MIGS act to enlarge Schlemm’s canal in order to enhance aqueous outflow, offering restoration of the natural pathway rather than altering the anatomical configuration of the angle. Some leave an implant in place, others do not. Some have relatively limited effectiveness but can be employed in a very large group of early glaucoma patients, while subconjunctival devices can potentially achieve efficacy comparable to filtration surgery but are associated with bleb-related complications. What they share is their capacity to lower IOP and the ability for surgeons to adopt a more stepwise approach to the management of their glaucoma patients, allowing more invasive surgery to be delayed or avoided.

This Special Issue aims to collate studies of the various different types of MIGS and offer readers an updated overview on what MIGS devices can offer today and how to select the best MIGS for patients. We will also look at effectiveness outcomes and understand if MIGS technological and clinical development is reaching the IOP lowering effect of filtration surgery. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Identifying therapeutic targets in glaucoma
• The role of Schlemm’s canal in the pathogenesis of glaucoma and its treatment
• Efficacy and longevity of canal-based MIGS
• Efficacy and longevity of trabecular meshwork MIGS devices and techniques
• Efficacy and longevity of suprachoroidal MIGS devices
• Early clinical evidence of cycloablation procedures
• Learning from the mistakes of failed MIGS in recent years
• Benefits of long-term MIGS effectiveness
• Managing complications in MIGS
• Reducing the medication burden in controlled patients with MIGS