This study is a multicentric, comparative, randomized, investigator-blinded, parallel group study to demonstrate the non-inferiority of DM934 in comparison with Théalose in terms of cornea and conjunctiva staining (Oxford score) on patients with moderate to severe ocular dryness, after 35 days of treatment

Inclusion Criteria:

• Subject with a moderate to severe dry eye syndrome needing artificial tears in the 3 months preceding the inclusion.

• Subject having used only artificial tears without preservative (NaCl 0.9%, Larmabak®) during 1 to 2 weeks before inclusion (up to 6 times a day) (given during wash-out period).

• Subject with a score ≥ 18 for the OSDI (Ocular Surface Disease Index).

• Subject with at least one eye with:

  • Global ocular staining (cornea and conjunctiva) ≥4 and ≤9 on the Oxford scale (0 to 15)

AND one of the following criteria:

• Schirmer test ≥ 3 mm/5 min and ≤ 9 mm/5 min OR

• Sum of 3 measurements of Tear film Break-Up Time (TBUT) ≤ 30s.

  • Subject, having given freely and expressly his/her informed consent.
  • Subject who is able to comply with the study requirements, as defined in the present CIP, at the Investigator's appreciation.
  • For applicable countries: subject being affiliated to a health social security system.
  • Female subjects of childbearing potential should use a medically accepted contraceptive regimen since at least 12 weeks before the beginning of the study, during all the study and at least 1 month after the study end.

Exclusion Criteria:

• Far best corrected visual acuity < 1/10 (according to Snellen Chart)

• Subject with severe ocular dryness with one of these conditions:

  • Eyelid or blinking malfunction
  • Corneal disorders not related to dry eye syndrome
  • Ocular metaplasia
  • Filamentous keratitis
  • Corneal neovascularization

• Subject with severe meibomian gland dysfunction (MGD).

• History of ocular trauma, infection or inflammation, not related to dry eye syndrome within the last 3 months prior to the inclusion.

• History of ocular allergy or ocular herpes within the last 12 months.

• Any troubles of the ocular surface not related to dry eye syndrome .

• Subjects who underwent ocular surgery, including laser surgery, in either eye within the last 6 months.

• Use of the following ocular treatments: isotretinoïd, cyclosporine, tacrolimus, sirolimus, pimecrolimus, punctual plugs during the month preceding the inclusion.

• Subjects who have received ocular therapy (either eye) with any ophthalmic medication, except tear substitutes, within 2 weeks prior to study start or expected to receive ocular therapy during the study.

• Any not stabilised systemic treatment, which can have an effect on performance or safety criteria, at the investigator appreciation.

• Pregnant or nursing woman or planning a pregnancy during the study.

• Subject deprived of freedom by administrative or legal decision.

• Subject in a social or health institution.

• Subject who is under guardianship or who is not able to express his/her consent.

• Subject being in an exclusion period for a previous study.

• Subject suspected to be non-compliant according to the Investigator's judgment.

• Subject wearing contact lenses during the study.

Depending on any journal publication of the results