Inclusion Criteria:
1. With 1 or 2 big toenail(s) damaged, which the clinical appearance of at least one great toenail is suggestive of onychomycosis.
2. Big toenails with distal mild to moderate subungual onychomycosis (OSI Score \< 16, no proximal or lunula involvement, and ≤50% nail involvement).
3. Able to understand and comply with protocol requirements and instructions, including applying the device.
4. Affiliated to a French Health insurance scheme.
5. Having signed an informed consent.
8\. With 1 or 2 big toenail(s) damaged by onychomycosis confirmed by positive culture for dermatophytes / fungi on at least one big toenail.
Exclusion Criteria:
1. Having a known allergy or hypersensitivity or contraindication to one of the constituents of UOA.
2. The toenail(s) to be included in the study present(s) severe onychomycosis (which should be treated by systemic drug), or is/are unstructured, has/have severe microcracking or severe onycholysis, or the nail(s) or nail(s) contour has/have severe lesions.
3. Having used any systemic antifungal treatment in the last 6 months before Baseline/pre-inclusion visit V0.
4. Having used any topical antifungal treatment in the last 3 months before Baseline/pre-inclusion visit V0.
5. With cutaneous pathology on studied zone (onychogryphosis, congenital ungual deformation, toe deformation or of the foot, hallux valgus, hallux rigidus, hallux extensus, toe claws or other pathologies than onychomycosis like angioma, dermatitis…).
6. With a condition or receiving medication which, according to the investigator's judgment, could jeopardize the safety of the subject.
7. Suffering from serious or progressive diseases (to investigator's discretion) such as uncontrolled diabetes, peripheral circulatory disease, lichen planus, immunosuppressive pathology, chronic venous insufficiency, Peripheral Arterial Obstructive Disease, delay, or lack of ungual growth etc.
8. May not respect the constraints imposed by the protocol.
9. Enrolled in another clinical trial or being in a period of exclusion from a previous clinical trial.
10. Woman of childbearing age (except menopausal, hysterectomised, sterilized) not using effective contraception (oral contraceptives, intra-uterine device, contraceptive implant, or condoms).
11. Person belonging to a population referred to in articles 64 (incapacitated subjects), 65 (minors), 66 (pregnant or breastfeeding women), 67 (persons performing mandatory military service, persons deprived of liberty, persons who, due to a judicial decision) and 68 (patients in emergency) of the MDR.
