Light reflex Rheography is a refined form of Photo-Plethysmography (PPG). This method is a non-invasive examination which measures the venous blood flow in the lower legs using infrared light, to evaluate the function of venous valves and the effectiveness of venous muscle pump. Venous blood volume changes in the sample area of skin are measured which reflect venous hemodynamic changes in the lower limb. This allows practitioner to diagnose whether symptoms of heaviness, aching and swelling in the legs that many people experience are indeed due to any significant vein disease.
LRR is a simple, inexpensive, and non-invasive bedside test that takes 10 minutes to perform. It is appropriate for the global assessment of calf-pump insufficiency regardless of whether it is caused by varicosities, the postphlebitic syndrome, or deep venous thrombosis. Therefore, very suitable as screening examination to evaluate the function of venous valves whereby measurements can be taken also through medical stockings.
It allows an early recognition of pathological changes so that an early therapy can slow down the development of the disease. For this reason, it is a good method to use as a pre-treatment selection test, especially for varicose veins.
No preparation is required for an LRR test.
The examination procedure includes two steps: At the beginning a 15-second exercise test must be made which is also called tip-toe-test or muscle pump test. During this exercise the muscle pump in the lower legs is activated to empty the veins what is the pre-condition to measure the refilling of the veins afterwards.
In a second step of the procedure, a wireless pressure probe shaped like a disc is put on each of the patients’s legs which measures the amount of blood present in a volume of the epidermis beneath the LRR probe. The change of the venous blood volume during the refilling of the veins is recorded and analysed by a practitioner.
Patients who maintain high pressures in the leg despite this ankle movement may have significant vein disease and require a full range of vein tests such as Ultrasound Duplex studies.