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Phacoemulsification Versus Phacoemulsification With Micro-bypass Stent

Phacoemulsification Versus Phacoemulsification With Micro-bypass Stent Implantation in Primary Angle Closure and Primary Angle Closure Glaucoma: Randomized Double-masked Clinical Trial

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03647033
Enrollment
32
Registered
2018-08-27
Start date
2015-10-14
Completion date
2017-08-12
Last updated
2018-10-31

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Primary Angle-Closure Glaucoma, Primary Angle Closure Without Glaucoma Damage

Keywords

istent, primary angle closure

Brief summary

Assessing the safety and efficacy of a micro-bypass stent in combination with cataract surgery in subjects with primary angle closure. Subjects are randomized into two arms: phacoemulsification cataract surgery alone versus phacoemulsification cataract surgery combined with the micro-bypass stent implantation. Post surgery intraocular eye pressure will be recorded to assess the efficacy of both arms.

Detailed description

Aim: To assess the safety and efficacy of the iStent trabecular micro-bypass stent (Glaukos Corporation, Laguna Hills, CA) in combination with cataract surgery in subjects with primary angle closure and mild to moderate primary angle closure glaucoma Method: Prospective, randomised controlled trial, blinded to patient and intra-ocular pressure measuring staff. 32 patients, 1:1 ratio, in 2 arms of phacoemulsification alone compared to phacoemulsification with iStent. Hypothesis: Phacoemulsification with micro-bypass stent has a better intraocular pressure (IOP) lowering effect compared to phacoemulsification alone in primary angle closure and primary angle closure glaucoma at 1 year after surgery. Importance: Primary angle closure and primary angle closure glaucoma are conventionally treated with eye drops that lower the intraocular pressure (IOP). Phacoemulsification/lens extraction can often help lower the eye pressure by widening the drainage angle and via ultrasound mechanisms, however, in some cases the IOP is not lowered, or even can cause the IOP to be higher. The iStent implant can be used together with phacoemulsification to lower the IOP and in Primary open angle glaucoma, it gives an additional 20% IOP reduction. It is unclear what effect the iStent has in primary angle closure or primary angle closure glaucoma as it has never been studied. It is important because primary angle closure glaucoma is much more common in the Singaporean Chinese population and the iStent can potentially be used to control the IOP instead of conventional eye drops and glaucoma surgery which have their own potential adverse effects. Potential Benefits: iStent with phacoemulsification may control the IOP better than phacoemulsification alone, reduce the need for IOP lowering medication after surgery, and prevent the need for glaucoma surgery in the future. Potential Risks: The iStent has risks of IOP spikes, bleeding in the anterior chamber and iStent dislocation.Phacoemulsification has the risks of: infection, bleeding, reduced vision, inflammation, posterior capsular rupture, vitreous loss, retinal detachment, endophthalmitis, suprachoroidal haemorrhage and Intraocular Lens dislocation.

Interventions

DEVICEiStent implantation

The iStent is a FDA and Health Sciences Authority (HSA) approved micro-bypass stent device that bypasses the trabecular meshwork (filtration membrane of the aqueous fluid exit pathway) and reroutes aqueous from the anterior chamber directly into canal of Schlemm and out of the eye. It lowers the intraocular pressure (IOP) by increasing the outflow of fluid from the eye from the micro-bypass. In angle closure, the lens has to be removed to create enough space for the iStent to be inserted.

Sponsors

Khoo Teck Puat Hospital
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)

Masking description

Shuffled envelope system. Patient will be blinded to the procedure. The intraocular pressure (IOP) measure and reader will be blinded to the procedure. There will be no planned breaking of randomization. Unplanned breaking will happen if any envelopes are damaged or lost. Unmasking will take place after 1 year post operation by the study team to inform the patient of the procedure.

Intervention model description

Single centre, randomised prospective trial, the patient and the intraocular pressure (IOP)checking staff will be blinded. Randomised by random envelope shuffle technique. 1:1 ratio allocation 2 arms: phacoemulsification alone and phacoemulsification and iStent. 16 patients in each arm, 32 patients in total. The post-operative management is the same for both arms After operation the patient will be followed up at day 1, week 1, week 2, months 1, 3, 6 and 12. At each visit the patient will have the following tests: Tonometry (IOP check) - Not to be taken by the operating surgeon, to be taken by 2 people, one IOP checker and one reader.

Eligibility

Sex/Gender
ALL
Age
21 Years to 80 Years
Healthy volunteers
No

Inclusion criteria

* able to provide informed consent * Previous diagnosis of Primary Angle Closure or Primary Angle Closure Glaucoma * Intraocular Pressure above 21mmHg at 3 separate visits * On 1 or more hypotensive medications * Pre-operative visual acuity of no better than 6/12

Exclusion criteria

* Other glaucoma diagnosis: Primary Open Angle Glaucoma, secondary glaucoma * Peripheral Anterior Synechiae in the nasal and inferior quadrant * Cloudy cornea affecting view for iStent implantation * Previous glaucoma surgery * History of Ocular trauma * Ocular surface disease * Pre-proliferative or proliferative diabetic retinopathy * Age related macular degeneration with macular scar or macular atrophy

Design outcomes

Primary

MeasureTime frameDescription
Change in Intraocular Pressure Between Baseline and 1 Year1 yearchange in mean unmedicated intraocular pressure between baseline and 1 year

Secondary

MeasureTime frameDescription
Change in Glaucoma Medications1 yearchange in number of topical glaucoma medications at 1 year post operation

Countries

Singapore

Participant flow

Participants by arm

ArmCount
Phacoemulsification Alone
routine phacoemulsification cataract surgery with intraocular lens implantation
16
Phacoemulsification and iStent
phacoemulsification cataract surgery with intraocular lens implantation combined with iStent implantation iStent implantation: The iStent is a FDA and Health Sciences Authority (HSA) approved micro-bypass stent device that bypasses the trabecular meshwork (filtration membrane of the aqueous fluid exit pathway) and reroutes aqueous from the anterior chamber directly into canal of Schlemm and out of the eye. It lowers the intraocular pressure (IOP) by increasing the outflow of fluid from the eye from the micro-bypass. In angle closure, the lens has to be removed to create enough space for the iStent to be inserted.
16
Total32

Baseline characteristics

CharacteristicPhacoemulsification AloneTotalPhacoemulsification and iStent
Age, Continuous69 years67 years65 years
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Asian
16 Participants32 Participants16 Participants
Race (NIH/OMB)
Black or African American
0 Participants0 Participants0 Participants
Race (NIH/OMB)
More than one race
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants0 Participants0 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants0 Participants0 Participants
Race (NIH/OMB)
White
0 Participants0 Participants0 Participants
Region of Enrollment
Singapore
16 participants32 participants16 participants
Sex: Female, Male
Female
9 Participants15 Participants6 Participants
Sex: Female, Male
Male
7 Participants17 Participants10 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 160 / 16
other
Total, other adverse events
2 / 1610 / 16
serious
Total, serious adverse events
0 / 160 / 16

Outcome results

Primary

Change in Intraocular Pressure Between Baseline and 1 Year

change in mean unmedicated intraocular pressure between baseline and 1 year

Time frame: 1 year

Population: intraocular pressure of participants measured in mmHg

ArmMeasureValue (MEAN)Dispersion
Phacoemulsification AloneChange in Intraocular Pressure Between Baseline and 1 Year15 mmHgStandard Deviation 2.5
Phacoemulsification and iStentChange in Intraocular Pressure Between Baseline and 1 Year14.7 mmHgStandard Deviation 3.1
Secondary

Change in Glaucoma Medications

change in number of topical glaucoma medications at 1 year post operation

Time frame: 1 year

ArmMeasureValue (MEAN)Dispersion
Phacoemulsification AloneChange in Glaucoma Medications0.75 number of glaucoma medicationsStandard Deviation 1
Phacoemulsification and iStentChange in Glaucoma Medications0.25 number of glaucoma medicationsStandard Deviation 0.68

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026