A Pilot Study Evaluating the Effects of 670 nm Photobiomodulation in Healthy Ageing and Age-Related Macular Degeneration.
Level 4 - case-series / case-control
Prospective single-arm pilot interventional study without a sham control group
PubMed 32252424 · doi:10.3390/jcm9041001
What was done
Researchers evaluated the functional and structural effects of daily morning 670 nm red light exposure (40 mW/cm², 4.8 J/cm² for 2 minutes via a hand-held device) in 31 patients with intermediate age-related macular degeneration (AMD) and 11 older adults (≥55 years) with normal retinas. Visual outcomes (best-corrected visual acuity, low luminance visual acuity, scotopic thresholds, and rod-intercept time) and structural outcomes (optical coherence tomography and color fundus photography) were measured at baseline, 1, 3, 6, and 12 months.
What was found
In healthy older eyes, scotopic thresholds improved by 1.77 dB (p = 0.03), while no other parameters showed clinically significant change. In eyes with intermediate AMD, there were no statistically significant improvements in any visual function or structural parameters at any time point up to 12 months. Five participants withdrew due to assessment intensity, and two were excluded after developing neovascular AMD.
Why it matters
This study fails to replicate previous smaller pilot reports of drusen regression and visual functional improvement, suggesting that 670 nm photobiomodulation does not alter the course of established intermediate AMD.
Limits
The study is limited by a small sample size (n = 42 total), lack of a randomized sham-control group, and notable participant attrition (5 voluntary withdrawals and 2 exclusions due to neovascular progression).
Cited by
- supports In a red light clinical trial on macular degeneration patients, healthy control subjects without macular degeneration showed significant improvements in vision, particularly in dark adaptation.