Effects of Photobiomodulation With Two Wavelengths of 630 and 810 nm on Diabetic Neuropathy

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes patients. Among different therapeutic approaches for treating DPN, low-level laser therapy (LLLT) or photobiomodulation (PBM) is a new promising non-invasive technique. This study aims to evaluate the effect of visible and infra-red LLLT on DPN.

Sixty DPN patients enrolled in a randomized-controlled study. The patients were randomly divided into the same population of control and laser groups. The patients in the laser group received LLLT with two wavelengths of 630 and 819 nm and conventional therapy, and those in the control group received conventional therapy alone. Irradiation of the patients lasted 15 minutes per session, and it was performed over the surface of each foot three times a week for 12 sessions. The patients were evaluated at baseline and at the end of the study with the Michigan Neuropathy Screening Instrument (MNSI) and microfilament test.

Patients’ sensation in the right foot in the monofilament test had increased from 22 (84.6%) to 26 (86.7%) (P = 0.000), and in the left foot it had increased from 20 (80%) to 25 (86.2%) (P = 0.001). The mean and standard deviation of the scores of section A of the Michigan questionnaire showed a statistically significant difference between the two groups (P < 0.05), but the B part scores of the Michigan test did not show a significant difference.

This study showed that the visible and infra-red LLLT significantly improved the symptoms of diabetic neuropathy without any side effects.