Assessment of the Efficacy of Microinvasive Glaucoma Surgery Techniques using an Oculopression Stress Test.

Stefan Siewert,Anselm Jünemann,Günther Kundt,Frank Thiesen,Dimitrios Karachalios,Anita Koschmieder,Rudolf F Guthoff,Thomas Stahnke,Franziska Kopp

doi:10.1055/a-1214-3875

Abstract

Glaucoma is one of the most common causes of blindness worldwide. The only evidence-based treatment to slow down the progression of glaucoma is the reduction of intraocular pressure (IOP) using local medication or through surgery. During the last years, a large number of microinvasive glaucoma surgery techniques (MIGS) has been developed, in order to reduce the IOP in glaucoma patients safely and effectively. Until now, efficacy of MIGS has been assessed mainly according to the postoperative IOP and the number of medications used. Results from long-term studies are rare or not available in the majority of the cases. In order to better evaluate the functionality of MIGS, a new examination method has been developed with the help of a new oculopressor device. In this study the efficacy of different MIGS techniques will be examined using the new oculopressor. At first, glaucoma patients that had previously received a MIGS surgery (iStent inject, XEN Stent, ELT) were examined with the new oculopression test. Their results were compared with those of non-operated patients and healthy individuals. Overall, 38 healthy subjects (group 1), 10non-operated patients (group 2), 19 patients after iStent inject implantation (group 3), 14 patients after XEN Stent implantation (group 4) and 5 patients after ELT (group 5) were examined. The new examination measures the IOP-reduction that occurs after oculopression and can be seen as an indirect measurement of the outflow facility of the eye. The IOP-reduction after oculopression differed among the study groups. Non-operated patients showed a significantly lower IOP-reduction compared to healthy individuals. Patients after iStent inject and XEN stent implantation showed a larger reduction of IOP after oculopression in relation to non-operated patients and their results approximated those of healthy individuals. These patients needed fewer medications postoperatively in relation to non-operated patients. Patients after ELT showed postoperatively a smaller reduction of IOP after oculopression compared to iStent inject and XEN stent patients. MIGS can increase the outflow facility of the eye in patients with glaucoma. Though ELT had the lowest impact on the aqueous outflow among the studied procedures in this study. The new test can help in the evaluation of current and further development of new MIGS in the future.

Highlights

Glaucoma is one of the leading causes of blindness worldwide
The first group consisted of 38 healthy individuals between the ages of 23 and 81 that had no history of previous ocular surgery or other eye disease
The oculopression curves of patients after XEN stent and iStent inject implantation were different compared to non-operated glaucoma patients and their results approximated those of healthy individuals

Summary

Introduction

Glaucoma is one of the leading causes of blindness worldwide. Global prevalence has been estimated to be 3.54% and the total number of people with glaucoma was 64.3 million in 2013 with a tendency to increase over the decades. (1). A number of minimally invasive glaucoma surgical techniques (MIGS) have been developed in order to minimize the risk of surgery and reduce the IOP in glaucoma patients safely and effectively. Given the abundance of different MIGS techniques and the lack of long-term studies, the development of an additional test that will examine the changes that occur in the outflow system of the eye after MIGS surgery will be able to better evaluate the IOP lowering potential of these procedures. The changes of IOP that occur after oculopression were measured in glaucoma patients who underwent MIGS surgery and were compared with the results of healthy individuals and glaucoma patients without previous surgery To our knowledge, this is the first clinical study that tests the efficacy of MIGS surgery using the new oculopressor and one of only few studies that assess aqueous dynamics after MIGS surgery in glaucoma patients (11)

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