Related Experiment Video
Updated: Jun 28, 2026
09:03
Optimizing Photoneuromodulation Techniques to Evaluate the Role of Green Light-Emitting Diodes in Pain Management
Published on: March 28, 2025
Blinding techniques in randomized controlled trials of laser therapy: an overview and possible solution
Ian Relf1, Roberta Chow, Marie Pirotta
1Department of General Practice, University of Melbourne, 200 Berkeley Street Carlton 3053, Victoria, Australia. i.relf@unimelb.edu.au.
Evidence-Based Complementary and Alternative Medicine : Ecam
|October 29, 2008
Summary
Low-level laser therapy shows promise, but most studies lack robust blinding. A new laser machine improves trial methodology by ensuring patient and operator blinding without staff involvement, enhancing reliability.
Area of Science:
- Biomedical Engineering
- Photomedicine
- Clinical Trial Methodology
Background:
- Low-level laser therapy (LLLT) demonstrates growing evidence for efficacy across diverse medical conditions.
- Existing research relies on randomized controlled trials (RCTs), but methodological limitations persist.
- Current LLLT trials often lack adequate blinding, introducing potential bias.
Purpose of the Study:
- To address deficiencies in LLLT trial methodology, specifically concerning blinding.
- To develop and preliminarily test a novel laser device capable of objective patient and operator blinding.
- To enhance the reliability and reduce bias in future LLLT clinical trials.
Main Methods:
- A systematic review of 51 double-blind randomized controlled trials (RCTs) was conducted.
- Analysis focused on the reporting and implementation of blinding and allocation concealment.
- A novel laser machine incorporating sealed randomization codes, decoy stimuli, and a physical barrier was developed and tested.
Main Results:
- While 58% of reviewed RCTs indicated LLLT benefits, less than 5% adequately addressed beam disguise or allocation concealment.
- Many existing blinding methods are susceptible to staff interference and bias.
- The novel laser machine successfully blinded patients and operators without requiring staff participation, overcoming limitations of previous methods.
Conclusions:
- Significant methodological flaws exist in current low-level laser therapy trials, particularly in blinding procedures.
- The developed laser machine offers a promising solution for improving the integrity of LLLT research.
- This innovation is expected to yield more reliable evidence on LLLT effectiveness by minimizing bias.
Related Concept Videos
01:11Blinding
Blinding is a commonly used method of not telling participants which treatment a subject is receiving. Blinding is a critical part of a randomized control trial or RCT. It reduces the bias that affects the results. In an RCT, blinding is used in the form of a placebo. A placebo effect occurs when untreated subjects falsely believe they have received the treatment and report improved symptoms. A placebo or a dummy treatment is administered to subjects to negate the bias caused by such an effect.
02:07Blind Procedures
Ideally, the people who observe and record the children’s behavior are unaware of who was assigned to the experimental or control group, in order to control for experimenter bias. Experimenter bias refers to the possibility that a researcher’s expectations might skew the results of the study. Remember, conducting an experiment requires a lot of planning, and the people involved in the research project have a vested interest in supporting their hypotheses. If the observers knew which child was...