Dry eye disease accounts for nearly 25% of ophthalmology consultations, making it a commonly encountered condition. When conventional treatments fail autologous serum in the form of eye drops, have been proposed as a therapeutic option. With the aim of standardizing the preparation of autologous serum eye drops in France, the main objective is to describe the absolute and relative differences (before and after filtration) in the concentrations of active molecules in the autologous serum of patients suffering from severe dry eye disease.

Sterility, which is a mandatory specification for eye drops, represents a critcial step in their manufacturing process. A review of the literature shows that 62% of articles (n=42) addressing the manufacturing process of autologous serum eye drops do not include a filtration step. Among those reporting filtration, slightly over 9% do not specify the porosity used, 4.8% use filters with a porosity of 0.45µm (clarifying filtration), and slightly over 23% use filters with a porosity ≤ 0.22µm ( sterilizing filtration). Several molecules present in autologous serum have been described in the literature, but five are widely recognized as the main contributors to its therapeutic efficacy: EGF, TGF-ß, IGF-1, Fibronectin, and Vitamin A. The impact of sterilizing filtration on the concentrations of thesemolecules in the final serum used for eye drop preparation therefore warrants investigation. Ten patients will be recruited from the ophthalmology department. A pre-screening phase will be conducted to identify eligible patients and propose the study participation. A dedicated follow-up consultation will be organized for inclusion. Serological tests will be performed on the blood samples of eligible patients. Only patients with negative serology for HIV, HBV, HCV and Treponema pallidum will be included. Their serum will be processed, at the Pharmaceutical Preparations Unit, to produce multiple aliquots following coagulation and centrifugation, with subsequentfiltration using 2 different filter materials, with 2 different porosities, or no filtration. These aliquots will then be sent to the Biochemistry department and Pharmacology department for the quantitative analysis of molecules of interest.

Inclusion Criteria:

• adult patients
• patients covered by health insurance
• patients managed by the Ophtalmology Department of the University Hospital of Limoges
• patients diagnosed with dry eyes syndrome, who have not responded to conventionnal treatments
• free, informed, written and signed consent

Exclusion Criteria:

• person incapable of consent
• legal guardianship or wardship
• patient who does not wish to know the results of serological tests

Secondary exclusion criteria:

- a positive serology for at least of of the following agents (HIV, HCV, HBV or syphilis)

The biological analyses are carried out blindly