Vienna Preserflo Cohort Study

Study Overview
=================
Brief Summary
-----------------
The Vienna Preserflo Microshunt Cohort Study is an observational study with a prospective postoperative examination in all glaucoma patients who had received a Preserflo Microshunt (PMS) as standalone procedure or in combination with cataract extraction in the time period between January and November 2019 at the Department of Ophthalmology, Medical University of Vienna. It is estimated that approximately 70 patients will be included of this cohort. The cohort will be invited for a prospective postoperative examination after 12 (±5) months of follow up. This examination shall comprise best corrected visual acuity, visual field test, intraocular pressure (IOP) measurement, slit lamp examination, fundus examination (optic disc and retina), gonioscopic assessment of PMS position, anterior segment optical coherence tomography (OCT) (shunt position, anterior chamber angle assessment, limbus shape analysis), corneal pachymetry, specular microscopy of corneal endothelial cells. Additionally, retrospective information concerning IOP, medication and visual fields of all patients will be collected from the Department of Ophthalmology as well as from the referring ophthalmologists where possible. Additionally, we will perform a comparison between two groups to compare differences in outcome measures.

Detailed Description
-----------------
During the inclusion period two slightly different surgical approaches have been used. At the beginning of the surgery, the conjunctiva is opened and the Tenon capsule is getting dissected from the sclera. In the first group of patients (group 1) we made a fornix based conjunctival opening, prepared a 1mm wide and long scleral pocket in 3mm distance from limbus and placed the PMS in the anterior chamber via a 25G needle track. In the second group (group 2) the conjunctival opening was 3.5 mm from the limbus, the scleral pocket was prepared at 3.5 mm distance from the limbus and a 27G needle was used. The outcomes of these two groups will be compared.

Official Title
-----------------
Vienna Preserflo Microshunt Cohort Study

Conditions
-----------------
Glaucoma, Glaucoma Surgery, Post-Op Complication, Efficacy, Self, Safety Issues

Intervention / Treatment
-----------------
* Device: Santen Preserflo Microshunt


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Glaucoma patients who received a PMS in the time period between January and November 2019 at the Department of Ophthalmology, Medical University of Vienna, Austria, will be invited Exclusion Criteria: Unwilling or unable to give informed consent. Pregnancy or lactation

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 95 Years

Sexes Eligible for Study
-----------------
All

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: Santen Preserflo Microshunt|The PMS is 8.5 mm long has an outer diameter of 350 μm and a lumen diameter of 70 μm. It has a fin sized 1.1 mm located 4.5 mm distally from the internal tip of the device and it consists of poly(styrene-b-isobutylene-b-styrene) SIBS. The device was implanted 1 year prior to the present study via an ab externo approach. At the beginning of the surgery, the conjunctiva was opened. In the first group of patients (group 1) we made a fornix based conjunctival opening, prepared a 1mm wide and long scleral pocket in 3mm distance from limbus and placed the PMS in the anterior chamber via a 25G needle track. In the second group (group 2) the conjunctival opening was 3.5 mm from the limbus, the scleral pocket was prepared at 3.5 mm distance from the limbus and a 27G needle was used. PMS guides aqueous humor from the anterior chamber to the subconjunctival space. The forming filtering bleb absorbs aqueous humor which leads to IOP reduction.|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| IOP | IOP in mmHg | one year | 
| Full success | IOP below 21 and IOP reduction of at least 20% from baseline without medication | one year | 
| Qualified success | IOP below 21 and IOP reduction of at least 20% from baseline with or without medication | one year | 
| Complications | Number of complications per eye | one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Re-intervention rate rate | Proportion of eyes requiring either needling revision of filtering bleb revision or any other glaucoma surgery | one year | 
| Medication rate | Number of patients who needed again eye pressure lowering medication | one year | 
| Average medication | Average number of different eye pressure lowering medication | one year | 
| OCT - shunt entry | Shunt position in chamber angle as determined by anterior segment OCT | one year | 
| OCT - shunt clearance | Shunt-cornea angle as determined by anterior segment OCT | one year | 
| OCT - shunt length | Shunt length in the anterior chamber as determined by anterior segment OCT | one year | 
| Corneal endothelial cell count | Corneal endothelial cell count in specular microscopy of corneal endothelium | one year |