Hypothesis: Fluorometholone (FML) 0.1% eyedrops topically applied 4 times a day for 22 days is more efficient than artificial tears (Liquifilm) in dry eye disease (DED) and ameliorates the worsening of the disease after exposure to an adverse controlled environment.

There will be 4 visits in 3 different days:

Visit 1 (V1). Inclusion in normalized controlled environment (NCE)

Visit 2 (V2). 21 days post-treatment. Data collected in NCE

Visit 3 (V3). 21 days post-treatment. Data collected in adverse controlled environment (ACE)

Visit 4 (V4). 22 days post-treatment. Recovery visit in ACE. Data collected in NCE

Inclusion Criteria:

• Age > 18 years
• Signed informed consent
• Subjects refer worsening in their pathologies when exposed to adverse environmental conditions in their daily life
• Fluorescein corneal staining ≥ 1in Oxford Scale
• Ocular surface disease index (OSDI) test > 12
• Tear breakup Time (TBT) ≤ 7 seconds in both eyes
• Schirmer test without anesthesia ≤ 10 mm in 5 minutes in both eyes
• Any concomitant medication that may affect dry eye syndrome, ocular surface or vision, must have started at least 3 months before screening visit, and there are no changes in dose expected during the study duration.
• Best corrected visual acuity at least 0.1 logMar at 6 meters with both eyes
• Current use of ophthalmic artificial tears at study inclusion.
• Signed informed consent
• Signed data protection consent

Exclusion Criteria:

• Sensitivity or known intolerance to any of the products used in the study
• Previous severe ocular inflammation or infections in the 6 previous months to study inclusion
• Any ocular pathology other than dry eye syndrome or atopic keratoconjunctivitis
• Any ocular surgery or trauma that may affect corneal sensitivity and / or normal tear distribution (refractive or cataract surgery) in the 6 previous months or any ocular or systemic surgery planned during the study duration that may affect the study as assessed by principal investigator.
• Use of contact lenses in the 3 previous months to study inclusion
• Use of any topical medication for pathologies other than dry eye syndrome.
• Any ocular topical treatment for dry eye syndrome with corticosteroids or non steroid anti-inflammatory drugs must have stopped 1 month before study inclusion. Any treatment with topical cyclosporin must have been stopped 3 months before study inclusion.
• Any uncontrolled severe systemic disease that may affect the eye (except for Sjögren Syndrome)
• Start, discontinuation or dose change during the study of antihistaminic, cholinergic agents, beta blockers, antidepressants or any other systemic medications with potential effect over tear film.
• Start of any systemic treatment that may affect dry eye syndrome, vision, ocular surface or intraocular pressure during the 3 previous months to study inclusion.
• Surgical / non surgical tear point occlusion in the 3 previous months to study inclusion or prevision during study duration for this procedure.
• Cup / disc ratio > 0.6
• History of intraocular pressure > 22 mm Hg within 2 months previous to study inclusion
• Pregnancy or breastfeeding women
• Inclusion in another research study in the previous 30 days to study inclusion