Dysphotopsia Following Laser Peripheral Iridotomy

February 11, 2013 updated by: Iqbal Ike Ahmed, Credit Valley EyeCare

Incidence of Visual Symptom Following Laser (Nd:YAG ) Peripheral Iridotomy (LPI) in Relation to Position of LPI

To establish the correlation of the location of the Nd:YAG laser peripheral iridotomy to the post operative visual symptoms experienced by some patients. The investigators hypothesize that fully uncovered laser peripheral iridotomy will produce less significant dysphotopsia, due to avoidance of the prismatic effect produced by the tear film than those covered.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Nd:YAG LPI is a frequently performed procedure for patients who have narrow angles at risk of acute angle closure glaucoma, pupillary-block conditions, chronic angle closure, and pigment dispersion syndrome. Most complications associated with the procedure are benign and include intraocular pressure (IOP) spike, transient uveitis, hyphema, corneal or lens damage and closure of the iridotomy. Visual disturbances have been also reported but only a few papers address this specific issue. The rate of these symptoms vary between 2.7% and 4%. It is believed that these symptoms are associated with the fact that light enters through the LPI and thus creating abnormal visual symptoms. Hence it has been suggested to carefully place the LPI so that the eyelid fully covers the LPI, therefore preventing light getting through. However, reports of patients with fully covered LPIs and visual disturbances have led to hypothesize the theory that even when fully covered by the eyelid, light can access through the LPI by a base-up prism created by the tear meniscus at the lid margin. Therefore, placement of the LPI, fully covered, partially covered or totally uncovered can potentially lead to equally significant symptoms. This study will attempt to address the issue of placement of the LPI in relationship with visual symptoms.

Study Type

Interventional

Enrollment (Actual)

214

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Mississauga, Ontario, Canada, L5L 1W8
        • Credit Valley EyeCare

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Able and willing to make the required study visit
  • Able and willing to give consent and follow study instructions
  • An indication to undergo laser peripheral iridotomy (narrow angles, occludeable angle at risk of acute angle closure, pupil block condition, chronic angle closure, pigment dispersion syndrome)

Exclusion Criteria:

  • Previous intraocular surgery
  • Best corrected visual acuity worse than 20/40
  • Asymmetrical ptosis of more than 2mm
  • Any active intraocular inflammation
  • Acute attack of angle closure glaucoma

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Superior Laser Peripheral Iridotomy
Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser peripheral iridotomy was performed on the superior aspect of the iris in the eye being treated. This will be in the 11 to 1 o'clock position.
Device: Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser
This device is used to perform the peripheral iridotomy on all patients. It is a standard of care approved device.
Other Names:
  • Nd:YAG Laser
Procedure: Nd:YAG Laser Peripheral Iridotomy
After application of topical anesthetic to the eye undergoing the LPI, the patient is seated at the laser machine. Abraham iridotomy lens filled with a viscous material will be used to facilitate the procedure. The thinnest area of the iris quadrant treated will be chosen. Nd:YAG Laser will be applied until iridotomy is opened satisfactory.
Other Names:
  • Nd:YAG LPI
Experimental: Temporal Laser Peripheral Iridotomy
Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser peripheral iridotomy was performed on the temporal aspect of the iris in the eye being treated. The position will be in the 2 to 4 o'clock in the left eye and 8 to 10 o'clock in the right eye.
Device: Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser
This device is used to perform the peripheral iridotomy on all patients. It is a standard of care approved device.
Other Names:
  • Nd:YAG Laser
Procedure: Nd:YAG Laser Peripheral Iridotomy
After application of topical anesthetic to the eye undergoing the LPI, the patient is seated at the laser machine. Abraham iridotomy lens filled with a viscous material will be used to facilitate the procedure. The thinnest area of the iris quadrant treated will be chosen. Nd:YAG Laser will be applied until iridotomy is opened satisfactory.
Other Names:
  • Nd:YAG LPI

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Presence of Linear Dysphotopsia
Time Frame: Baseline (Time =0),1 month
The change in presence of linear dysphotopsia from baseline (prior to intervention) to 1 month after the Nd:YAG laser intervention is performed.
Baseline (Time =0),1 month

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Presence of Visual Dysphotopsia
Time Frame: Baseline (Time = 0), 1 month
This includes Halo, Crescent, Ghost Images, Glare, Shadows. This records the change in the presence of these symptoms from baseline (prior to intervention) and 1 month after the Nd:YAG laser intervention.
Baseline (Time = 0), 1 month
Pain Experienced
Time Frame: Procedure (Time = 0)
The pain experienced when the Nd:YAG procedure is performed. This is on a scale of 0-10 with 0 being no pain and 10 the most severe pain imaginable.
Procedure (Time = 0)
Nd:YAG Laser Power Used
Time Frame: Procedure (Time = 0)
The amount of laser power used on the Nd:YAG laser to perform the intervention.
Procedure (Time = 0)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Credit Valley EyeCare

Investigators

  • Principal Investigator: Iqbal Ike K Ahmed, MD, University of Toronto, Toronto, Canada. University of Utah, Salt Lake City, USA
  • Study Director: Vanessa Vera, MD, University of Toronto, Canada

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

January 1, 2008

Primary Completion (Actual)

January 1, 2009

Study Completion (Actual)

January 1, 2009

Study Registration Dates

First Submitted

December 20, 2012

First Submitted That Met QC Criteria

December 31, 2012

First Posted (Estimate)

January 1, 2013

Study Record Updates

Last Update Posted (Estimate)

February 13, 2013

Last Update Submitted That Met QC Criteria

February 11, 2013

Last Verified

February 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CVEC-LPI

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Narrow Angle Patients at Risk for Angle Closure Glaucoma

Clinical Trials on Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Saint Lucia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe