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.