Micropulse for Suppression of Diabetic Macular Edema

N/ACompletedNCT03519581

University of California, Davis19 enrolled

Overview

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.

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

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Conditions

Diabetic Macular Edema

Interventions

Micropulse Laser TreatmentDEVICE

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.

Sham TreatmentDEVICE

Participant's study eye will be dilated prior to being comfortably seated at the slit lamp for treatment. No actual laser treatment will occur.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Locations (1)

University of California, Davis

Sacramento, California, United States

Outcomes

Primary Outcomes

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.

Time frame: 6 months

Secondary Outcomes

Visual Acuity at 6 Month

Visual acuity measured using ETDRS

Time frame: 6 months

Low Luminance Visual Acuity at 6 Months

Low Luminance Visual acuity measured with a 2.0-log unit neutral density filter

Time frame: 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.

Time frame: 6 months

Central Subfield Thickness (CST) at 6 Months

Using Heidelberg Spectralis device to measure central subfield thickness (CST)

Time frame: 6 months

Microperimetry Average Threshold at 6 Month

Performed using the Macular Integrity Assessment (MAIA) Instrument

Data from ClinicalTrials.gov

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