Open, Non-comparative Study to Evaluate the Effectiveness and Safety of the Medical Device KOS® S in the Correction of Moderate or Severe Infraorbital Hollowing

Inclusion Criteria: * Signed informed consent by the subject * Females and males ≥ 22 years of age * Has "Moderate" or "Severe" infraorbital hollowing (grade 2 or 3 on the AIHS) on the 5-point AIHS for each eye as assessed by the Evaluating Investigator (i.e., both eyes must qualify but do not need to have the same score) * Ability to follow study instructions and likely to complete all required visits * Reliable methods of contraception which result in a low failure rate (i.e. less than 1 % per year) for women of childbearing potential, e.g. implants, injectables, combined oral contraceptives, some intrauterine-devices, sexual abstinence or vasectomized partner) for the entire study duration. Exclusion Criteria: 1. Has hyperpigmentation in the infraorbital area (does not include dark circles under the eyes, not due to hyperpigmentation). 2. Has ever received permanent facial implants (e.g., polymethylmethacrylate, silicone, polytetrafluoroethylene) anywhere in the face or neck, or is planning to be implanted with any of these products during the study 3. Has ever undergone fat injections above the subnasale or is planning to undergo this procedure during the study 4. Has tattoos, piercings, facial hair (i.e., beard, moustache), or scars that would interfere with visual assessment of the infraorbital hollows 5. Has undergone volume augmentation with semi-permanent dermal fillers (e.g., calcium hydroxyapatite, poly-L-lactic acid) or temporary dermal fillers in the malar area, temples, or around the eyes within 12 months before enrolment or is planning to undergo such treatment during the study 6. Using any new over-the-counter or prescription oral or topical, anti-wrinkle products within 30 days before enrolment or is planning to begin using such products during the study. Subjects who have been on a regimen of such products for at least 30 days are eligible for the study if they intend to continue their regimen throughout the study) 7. Has congenital or acquired deformities of theface, lipodystrophy, or poor nutritional status 8. Has active or recurrent inflammation or infection in either eye 9. History of or active autoimmune disease/immune deficiency 10. Taking medications and/or substances known to increase coagulation time (e.g., aspirin, ibuprofen, or herbal supplements) 10 days prior to treatment 11. Simultaneousness with laser therapy or deep chemical peeling 12. Prone to hypertrophic scars 13. History of allergy to hyaluronic acid or any of the product's components 14. History of allergy to lidocaine or local anaesthesia of amide compounds 15. Known case of porphyria 16. Pregnancy or lactation 17. Have a condition or be in a situation that, in the physician's opinion, may put the subject at significant risk, may confound the study results, or may interfere significantly with the subject's participation in the study 18. Untreated epilepsy 19. Hypersensitivity to gram positive bacterial proteins as hyaluronic acid is produced by Streptococcus type bacteria