Micropulse for Suppression of Diabetic Macular Edema

Not Applicable

Completed

Conditions: Diabetic Macular Edema

Interventions: Device: Micropulse Laser Treatment
Device: Sham Treatment

Registration Number: NCT03519581

Lead Sponsor: University of California, Davis

Brief Summary: 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.

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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 19

Inclusion Criteria

Age >=18 years
Type 1 or type 2 diabetes mellitus
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
Best corrected visual acuity of 20/32 or better on ETDRS testing

Exclusion Criteria

Macular edema from causes other than DME
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)
An ocular condition is present other than DME which may contribute to macular edema (i.e/vein occlusion, ERM, uveitis, RP, etc...).
Cataract that in the opinion of the investigator may alter visual acuity throughout the course of the study
History of prior laser or other surgical, intravitreal, or peribulbar treatment for DME in the study eye within the prior 6 months.
More than 4 prior intraocular injections for treatment of DME at any time
More than 1 prior focal/grid macular photocoagulation session for treatment of DME at any time
History of topical steroid or NSAID treatment within 30 days prior to randomization
History of PRP within 4 months prior to randomization or anticipated need for PRP in the 6 months following randomization.
Any history of vitrectomy.
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
History of YAG capsulotomy performed within 2 months prior to randomization.
Aphakia
Exam evidence of external ocular infection, including conjunctivitis, chalazion, or significant blepharitis

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Micropulse Laser Treatment	Micropulse Laser Treatment	Subjects assigned to the micropulse laser arm of the trial will undergo the following procedures: 1. Confirmation of the subject's identity and eye to be treated 2. Subject's eye will be dilated 3. Subject will be positioned at the slit lamp for treatment 4. Application of subthreshold micropulse laser using the Iridex IQ577 laser unit. (intermittent pulsed energy) in a 7 X 7 grid pattern surrounding the fovea.
Sham Treatment	Sham Treatment	Subjects assigned to the sham arm of the trial will undergo the following procedures: 1. Confirmation of the subject's identity and eye to be treated 2. Subject's eye will be dilated 3. Subject will be positioned at the slit lamp for treatment 4. No Actual laser treatment will occur

Primary Outcome Measures

Name	Time	Method
Percentage of Subjects With Vision Loss to 20/40 or Worse	6 months	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.

Secondary Outcome Measures

Name	Time	Method
Visual Acuity at 6 Month	6 months	Visual acuity measured using ETDRS
Low Luminance Visual Acuity at 6 Months	6 months	Low Luminance Visual acuity measured with a 2.0-log unit neutral density filter
Contrast Sensitivity at 6 Months	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.
Central Subfield Thickness (CST) at 6 Months	6 months	Using Heidelberg Spectralis device to measure central subfield thickness (CST)
Microperimetry Average Threshold at 6 Month	6 months	Performed using the Macular Integrity Assessment (MAIA) Instrument