Overview of MIGS

The term, minimally- or micro-invasive glaucoma surgery (MIGS), has entered common ophthalmic parlance and is playing an increasing role in the management of glaucoma patients. In common, the devices and procedures referred to are safer, less tissue invasive and associated with faster recovery than traditional filtering surgery, such as trabeculectomy or aqueous shunt implantation. MIGS can be categorized according to the tissue they target (or bypass): trabecular meshwork (TM) MIGS, subconjunctival MIGS, suprachoroidal MIGS and newer cycloablation procedures. A number of MIGS devices and techniques (e.g. TM MIGS) have relatively modest efficacy, but potential utility in a very large group of glaucoma patients with disease that is insufficiently severe to justify the invasiveness of conventional filtration surgery and the consequent intensity of postoperative care yet, burdened with medication and the attendant side effects and compliance issues thereof. On the other hand, subconjunctival MIGS devices, which are associated with bleb-related complications, can potentially achieve efficacy approaching that of traditional filtering surgery and are appropriate in selected individuals when larger IOP reductions are required, the exception being cases where glaucoma is very advanced. This book covers the techniques that are most commonly regarded as eligible to sit under the MIGS umbrella. Irrespective of the modest efficacy of many MIGS devices and techniques, the favourable safety profile lowers the threshold for early glaucoma surgery, especially when combined with cataract surgery, potentially delaying the requirement for more invasive surgery and associated risks.

Ex-PRESS mini-shunt implanted in a pregnant patient with iridocorneal endothelial syndrome

Introduction: The failure rate of both filtration surgery and of aqueous shunt implantation is higher for iridocorneal endothelial syndrome than in other scenarios, due to the continuous proliferation of abnormal endothelial cells over the trabecular meshwork and the filtration area and also due to the more pronounced cicatrizing response shown by these young patients. We present the first case ever described in the literature of a pregnant patient with iridocorneal endothelial syndrome and uncontrolled ocular hypertension who was implanted an Ex-PRESS mini-shunt. Clinical case: A 35-year-old female presented with diminution of vision in the left eye for 2 months. She was 20 weeks pregnant. Her visual acuity was 20/20 in right eye and 20/25 in left eye, and intraocular pressure was 11 mmHg in right eye and 34 mmHg in left eye. Slit lamp biomicroscopic examination revealed no alterations in right eye, whereas left eye showed corectopia and uveal ectropion, stroma of iris’ sectoral atrophy and moderate corneal epithelial edema. Gonioscopy showed some anterior iris synechiae in left eye. Fundus evaluation was normal. Based on clinical features and examination, the diagnosis of left eye iridocorneal endothelial syndrome with decompensated intraocular pressure was made. She was prescribed topical timolol (0.5%) and dorzolamide. As a result of uncontrolled intraocular pressure and the impossibility to prescribe other hypotensive treatment available due to her being pregnant, it was decided to perform surgery in left eye using an Ex-PRESS mini-shunt and Ologen®; 6 months post surgery, intraocular pressure was 9 mmHg with no need for hypotensive treatment. The cornea was transparent, and the patient maintained her left eye visual acuity. Conclusions: Ex-PRESS mini-shunt can be considered a surgical option for iridocorneal endothelial syndrome. Its composition allows the ostium to remain open and the device triggers a milder postoperative inflammatory response. In our particular case, taking into account that the subject was a young, phakic, pregnant woman, whose intraocular pressure had to be closely controlled and we had to ensure that her postoperative care included as few drugs and as few reoperations as possible, we thought that using this device was the most appropriate option.