The primary goal of this study was to assess, in vivo, the efficacy of the medical device Invisible insoles LIGHT LEGS in improving venous return in subjects affected by this problem after 14 days of medical device use, by self-assessment, filling in questions regarding Quality of Life, in comparison to the baseline.

The secondary goals of this study were (1) to assess in vivo the perception of subjects about the rapid relief felt after 7 days of using the same medical device, by selfassessment, filling-in three subjective evaluation questions, and (2) to assess in vivo the usability of the subjects regarding the same medical device after 14 days of its use, by self-assessment, filling in subjective evaluation questions.

Inclusion Criteria:

• Gender: Female/Male;
• Age: with 18 years old and older;
• Having signed an Informed Consent Form (ICF);
• Willingness, ability and likeliness to comply with all the study procedures and restrictions;
• Ability to give informed consent;
• Available during the entire study period;
• Understanding Portuguese language: Portuguese-speaking subjects capable of reading the documents;
• Affected by a symptomatic venous return problem;
• With a score >14 from the question 1 to 11 of the adapted CIVIQ questionnaire (each question scored on a scale from 0 to 4);
• Agree to wear open shoes suitable for insoles throughout the study, for at least 8 hours per day (with a heel <5cm);
• Having a shoe size of 36 to 41;

Exclusion Criteria:

• Known allergy or known history of hypersensitivity to the components of the investigational device and related compounds;
• Currently participating in another clinical study that may interfere with the study;
• Diagnosed skin diseases and/or cutaneous alterations on the test region (feet) that may impair the study (for example tattoos, marks, burns, scars, etc.);
• Diagnosed diseases that may impair the study (including but not limited to: Diabetes, Arteritis, Phlebitis, etc);
• Under pharmacological treatments on the 30 days previous to the beginning of the study and during the entire period of the study that may impair it (including but not limited to: inflammatory drugs, any drug that might cover the signs and symptoms, drugs with arterial or venous indications, etc.);
• Having applied any type of topical product (pharmaceutical, cosmetic or other) with similar effect of the medical device under study, on the test region (feet) during the study, besides the investigational device;
• Having a stage of CVD C3 on the CEAP classification;
• Having had a traumatic or neurological history in the last 6 months;
• Wearing an orthopaedic insole made by a health professional;
• Having a significant and disabling lower limb pain;
• Having a significant and disabling back pain;
• Having a contraindication to wearing insoles and open shoes;
• Wearing open shoes with an anatomical shape (e.g. Birkenstock);
• Pregnancy or intention to conceive during the study;
• Breast-feeding.