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Phacoemulsification Versus Phacoemulsification With Micro-bypass Stent

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03647033
Recruitment Status : Completed
First Posted : August 27, 2018
Results First Posted : October 2, 2018
Last Update Posted : October 31, 2018
Information provided by (Responsible Party):
Khoo Teck Puat Hospital

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.

Condition or disease Intervention/treatment Phase
Primary Angle-Closure Glaucoma Primary Angle Closure Without Glaucoma Damage Device: iStent implantation Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 32 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
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.

Masking: Double (Participant, 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.

Primary Purpose: Treatment
Official Title: Phacoemulsification Versus Phacoemulsification With Micro-bypass Stent Implantation in Primary Angle Closure and Primary Angle Closure Glaucoma: Randomized Double-masked Clinical Trial
Actual Study Start Date : October 14, 2015
Actual Primary Completion Date : August 12, 2016
Actual Study Completion Date : August 12, 2017

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Glaucoma

Arm Intervention/treatment
No Intervention: phacoemulsification alone
routine phacoemulsification cataract surgery with intraocular lens implantation
Experimental: phacoemulsification and iStent
phacoemulsification cataract surgery with intraocular lens implantation combined with iStent implantation
Device: 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.

Primary Outcome Measures :
  1. Change in Intraocular Pressure Between Baseline and 1 Year [ Time Frame: 1 year ]
    change in mean unmedicated intraocular pressure between baseline and 1 year

Secondary Outcome Measures :
  1. Change in Glaucoma Medications [ Time Frame: 1 year ]
    change in number of topical glaucoma medications at 1 year post operation

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   21 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts 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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03647033

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Khoo Teck Puat Hospital
Singapore, Singapore, 768828
Sponsors and Collaborators
Khoo Teck Puat Hospital
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Principal Investigator: Philemon Huang, MMed, FAMS National Healthcare Group, Singapore
  Study Documents (Full-Text)

Documents provided by Khoo Teck Puat Hospital:
Study Protocol  [PDF] October 6, 2015
Informed Consent Form  [PDF] October 6, 2015

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Responsible Party: Khoo Teck Puat Hospital Identifier: NCT03647033    
Other Study ID Numbers: 2015/00644
First Posted: August 27, 2018    Key Record Dates
Results First Posted: October 2, 2018
Last Update Posted: October 31, 2018
Last Verified: September 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Product Manufactured in and Exported from the U.S.: Yes
Keywords provided by Khoo Teck Puat Hospital:
primary angle closure
Additional relevant MeSH terms:
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Glaucoma, Angle-Closure
Ocular Hypertension
Eye Diseases