Evaluation of Performance and Safety of Eye Drops With Hyaluronic Acid 0.30% and 0.15%

This is a profit, multicentric, prospective, open-label, non-pharmacological clinical investigation aim to evaluate the efficacy and tollerability of two types of eye drops containing Hyaluronic acid (HA) with different concentration as 0.30% (BLUgel A) and 0.15% (BLUyal A). the study will consider patients affected by moderate to severe dry eye syndrome which will be treated with HA 0.30% while patients affected by mild dry eye syndrome will be treated with HA 0.15%.Dry eye syndrome (DES) is defined as a multifactorial disease of the ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface.Based on the available background on the use of HA in the management of DES, this investigation has been designed to assess the efficacy of HA- and amino acid-based product BLUgel A free and BLUyal A free, in patients with moderate to severe and mild dry eye syndrome, respectively.

Inclusion Criteria: Patients who meet all the following criteria at the screening/baseline visit will be considered as eligible for the investigation: 1. Patients having signed written informed consent to participate in the investigation obtained according to Good Clinical Practice (GCP); 2. Patients having an age ≥ 18 years; 3. Patients with diagnosis of dry eye syndrome (according to Tear Film and Ocular Surface Society \[TFOS\] Dry Eye Workshop \[DEWS\] definition); 4. Diagnosis of dry eye syndrome for the investigation assessed through at least the following exams: slit lamp examination (SLE), tear (lacrimal) meniscus exam, Schirmer's test I, TFBUT, cornea and conjunctiva staining, IDEEL questionnaire ("Dry Eye Symptom-Bother" module); 4a) Diagnosis of mild dry eye syndrome will be based on the following criteria: * TFBUT 7-10 sec * Schirmer's test I 7-10 mm * Fluorescein staining of the cornea and conjunctiva (NEI scale value) \