Micropulse for Suppression of Diabetic Macular Edema (PULSE)

Diabetic retinopathy is one of the most common complications of diabetes and diabetic macular edema (DME) is one of the most common causes of vision loss in diabetes.

The purpose of this study is to determine if early intervention with micropulse laser treatment in eyes with good visual acuity (20/32 or better) will improve or stabilize vision loss due to the complications of diabetic macular edema.

Study Overview

• Status: Completed
• Conditions: Diabetic Macular Edema
• Intervention / Treatment: Device: Micropulse Laser Treatment; Device: Sham Treatment

Detailed Description

This is a randomized, controlled clinical trial comparing subthreshold micropulse laser versus sham laser treatment for eyes with diabetic macular edema with good visual acuity of 20/32 or better.

Subjects will be randomized to receive either subthreshold micropulse laser treatment or no treatment (sham). Randomization will occur as a ratio of 2:1 and will take place during the clinic visit.

Subjects selected for the study will undergo a complete ophthalmic examination, including measurements of best corrected visual acuity, low luminance visual acuity, contrast sensitivity (using ETDRS testing with a masked coordinator), intraocular pressure, slit lamp exam including documentation of lens status, and dilated funduscopic exam with standard dilating agents used at the UC Davis Eye Center. Subjects will then undergo baseline imaging including Spectral Domain Ocular Coherence Tomography (SD-OCT), fundus autofluorescence (FAF) and microperimetry testing. Both the use of OCT, FAF, and microperimetry testing are within the standard of care for the management of DME.

The duration of an individual subject's participation in the study will be two years which will include at least 10 total visits at various time points including on the day of enrollment, followed by 1, 3, 6, 9, and 12, 15, 18, 21, 24 months after the day of enrollment.

The subjects in the treatment arm will be treated on the day of randomization by SML photocoagulation using the Iridex IQ577 laser unit with TxCell scanning laser delivery system.

Subjects in the sham treatment arm will undergo the same set up procedures as those receiving the laser treatment, however, no actual laser treatment will occur.

Subjects will then return to the clinic for repeat ophthalmic exam, OCT imaging, and microperimetry at 1 month, 3 month, 6 month, 9 month, 12 month, 15 month, 18 month, 21 month and 24 month time points, which is similar in frequency as standard of care.

Patients in the treatment arm are eligible for repeat SML laser at any subsequent visit if there is any decline in vision (1 or more ETDRS lines) or worsening in edema (>10% increase), at the discretion of the treating physician. If vision declines to 20/40 or worse at any study visit, patients in the treatment arm will undergo repeat treatment with SML laser, while those in the sham arm will undergo repeat sham laser.

• Study Type: Interventional
• Enrollment (Actual): 19
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Sacramento, California, United States, 95817
      • University of California, Davis

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age >=18 years
2. Type 1 or type 2 diabetes mellitus

3. Clinical evidence of center-involved DME confirmed on OCT, and defined by OCT

   Central Subfield (CSF) thickness at the time of randomization by the following:

   1. Zeiss Cirrus: 275μ in women, and 290μ in men
   2. Heidelberg Spectralis: 290μ in women, and 305μ in men
4. Best corrected visual acuity of 20/32 or better on ETDRS testing

Exclusion Criteria:

1. Macular edema from causes other than DME
2. An ocular condition is present such that in the opinion of the investigator, visual acuity would not improve from resolution of macular edema (i.e/foveal atrophy, pigment abnormalities, dense hard exudates)
3. An ocular condition is present other than DME which may contribute to macular edema (i.e/vein occlusion, ERM, uveitis, RP, etc…).
4. Cataract that in the opinion of the investigator may alter visual acuity throughout the course of the study
5. History of prior laser or other surgical, intravitreal, or peribulbar treatment for DME in the study eye within the prior 6 months.
6. More than 4 prior intraocular injections for treatment of DME at any time
7. More than 1 prior focal/grid macular photocoagulation session for treatment of DME at any time
8. History of topical steroid or NSAID treatment within 30 days prior to randomization
9. History of PRP within 4 months prior to randomization or anticipated need for PRP in the 6 months following randomization.
10. Any history of vitrectomy.
11. History of major ocular surgery (cataract extraction, scleral buckle, any intraocular surgery, etc.) within prior 4 months or anticipated within the next 6 months following randomization
12. History of YAG capsulotomy performed within 2 months prior to randomization.
13. Aphakia
14. Exam evidence of external ocular infection, including conjunctivitis, chalazion, or significant blepharitis

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Micropulse Laser Treatment; Subjects assigned to the micropulse laser arm of the trial will undergo the following procedures: Confirmation of the subject's identity and eye to be treated; Subject's eye will be dilated; Subject will be positioned at the slit lamp for treatment; Application of subthreshold micropulse laser using the Iridex IQ577 laser unit. (intermittent pulsed energy) in a 7 X 7 grid pattern surrounding the fovea.	Device: Micropulse Laser Treatment; Participant's study eye will be dilated prior to being comfortably seated at the slit lamp for treatment. Application of micropulse laser on retinal surface will occur using TxCell Scanning Delivery System in a 7 x 7 grid to surround the fovea.
Placebo Comparator: Sham Treatment; Subjects assigned to the sham arm of the trial will undergo the following procedures: Confirmation of the subject's identity and eye to be treated; Subject's eye will be dilated; Subject will be positioned at the slit lamp for treatment; No Actual laser treatment will occur	Device: Sham Treatment; Participant's study eye will be dilated prior to being comfortably seated at the slit lamp for treatment. No actual laser treatment will occur.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Subjects With Vision Loss to 20/40 or Worse	BCVA measured using ETDRS testing. The study endpoint was reached if the study patient experienced vision loss of ≥10 letters (≥2 lines) at any visit or 5-9 letters (1-2 lines) at 2 consecutive visits ≤28 days apart, based on the criteria for initiating anti-VEGF therapy as defined in the DRCR Protocol V study.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual Acuity at 6 Month	Visual acuity measured using ETDRS	6 months
Low Luminance Visual Acuity at 6 Months	Low Luminance Visual acuity measured with a 2.0-log unit neutral density filter	6 months
Contrast Sensitivity at 6 Months	Contrast sensitivity is measured using a single, large letter size (20/60 optotype) with contrast varying across groups of letters. The contrast sensitivity chart (CS) uses letters whose contrast varies from high to low. The scale is 0.0 (minimum) to 2.0 (maximum). A higher score equates to a better outcome. The score is based on the contrast of the last group in which 2 or 3 letters were correctly read. A score of 2.0 indicates normal CS of 100%. Scores < than 2.0 signify poorer CS; scores < than 1.5 is consistent with visual impairment; a score < than 1.0 represents visual disability.	6 months
Central Subfield Thickness (CST) at 6 Months	Using Heidelberg Spectralis device to measure central subfield thickness (CST)	6 months
Microperimetry Average Threshold at 6 Month	Performed using the Macular Integrity Assessment (MAIA) Instrument	6 months

Collaborators and Investigators

• Sponsor: University of California, Davis
• Collaborators: IRIDEX Corporation
• Investigators: Principal Investigator: Glenn Yiu, MD, PhD, University of California, Davis

Publications and helpful links

Helpful Links

• Learn more or sign up for the study here!

Study record dates

Study Major Dates

• Study Start (Actual): April 20, 2018
• Primary Completion (Actual): January 31, 2023
• Study Completion (Actual): January 31, 2023

Study Registration Dates

• First Submitted: April 26, 2018
• First Submitted That Met QC Criteria: May 8, 2018
• First Posted (Actual): May 9, 2018

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: December 13, 2024
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: micropulse laser; DME
• Additional Relevant MeSH Terms: Eye Diseases; Retinal Diseases; Retinal Degeneration; Macular Degeneration; Edema; Macular Edema
• Other Study ID Numbers: 1141752

Drug and device information, study documents

• 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.: No