The aim of this study is to determine the effectiveness of lowering intraocular pressure and safety profile of the Paul Glaucoma Implant (Advanced Ophthalmic Innovations, Singapore). This is a non-comparative and single-arm observational study and all the participants were recruited between 1 Dec 2017 and 1 Dec 2018. Patients between age 21 - 80 years with glaucoma and an IOP deemed poorly controlled by the study team despite on maximal tolerated medical therapy were included in this study. The participants were recruited from 6 tertiary ophthalmology centers including National University Hospital, Singapore, Moorfields Eye Hospital, United Kingdom, St Thomas' Hospital, United Kingdom, Chulalongkorn University and Hospital, Thailand, International Specialist Eye Centre, Malaysia and Chinese University of Hong Kong, Hong Kong. All the eyes were followed-up for a period of 12 months after surgery. The examination and investigations included best corrected Snellen visual acuity, slit lamp examination, goldman applanation tonometry (GAT), dilated fundus examination and optic nerve head imaging. The participants are reviewed before surgery, 1 day, 1 week, 1 month, three months, 6 months and 12 months after surgery. All the data were captured in a standardized data-collection form for analysis. The primary outcome measure was failure, if was prospectively defined as IOP more than 21mmHg or less than a 20% reduction compared to pre-operative baseline on 2 consecutive visits after 3 months, IOP less than 6 mmHg on 2 consecutive visits after 3 months, reoperation for IOP-related indication, loss of light perception vision, or removal of the implant for any reason. Intraocular pressure outcomes, number of IOP-lowering medications and the rate of surgical complications were secondary outcome measures in this study.

Inclusion Criteria:

• Age 21 - 80 years with glaucoma
• Poorly controlled intraocular pressure

Exclusion Criteria:

• Unable to give informed consent
• Age below 21 or above 80 years
• Without any suitable quadrants for tube shunt implant

Patients between age 21 - 80 years with glaucoma and an IOP deemed poorly controlled by the study team despite on maximal tolerated medical therapy were included in this study