Matthew Starr, MD
Vitreoretinal Surgeon
Mayo Clinic
Dr. Judy Kim presented for the first time, the DRCR network’s Protocol AE, examining the effect of photobiomodulation (PBM) for DME in eyes with good visual acuity. Dr. Kim reported that this protocol had a record rate for enrollment with 100% completion rate.
As a background, PBM is irradiation to tissue using light in the far read to near infrared region spectrum (630-900 nm) and in systemic diseases has been shown to improve wound healing and reduce oxidative damage. This prompted the DRCR network to investigate its use in patients with DME. Protocol AE was a phase 2 study which sought to determine short term effect on central subfield thickness at 4 months after initiating PBM therapy compared to placebo in eyes with CI-DME and good visual acuity (>20/25 or better).
The PBM device was placed over the study eye and turned on for 90 seconds and then automatically turns off, emitting 670nm of irradiation for a total of 4.5 Joules of energy. The device was used twice a day for 4 months. The device recorded when it was used to determine compliance. The placebo arm also used the same device; however, this device emitted a white light without any photobiomodulation. Study visits occurred at 1, 2, 3, and 4 months with 135 eyes randomized 1:1 to each cohort.
The study found no differences in baseline demographic or ocular characteristics between the cohorts. In regards to the primary outcomes, the study found no difference in mean change in CST from baseline to month 4 with no change in mean visual acuity between the PBM and placebo cohorts. There were also no differences in the number of eyes with a loss of 5 or more letters between the groups.
Dr. Kim concluded that PBM is safe and well tolerated, but not effective for treatment of DME and thus there will be no phase 3 from the DRCR, however, she encouraged others to continue this type of work as this method was safe and well tolerated and may be applicable to other areas within retina.
