The goal of this study is to better understand how eye blinking behavior is linked to the stability of the tear film, in adults aged 18 to 65 years, with or without symptoms of dry eye.

The main questions are:

• Do the results of a New Blink Task reflect tear film stability ?
• How are the blink related metrics in relation with each other? Researchers will compare two groups of participants-those without dry eye symptoms and those with dry eye symptoms-to see if blinking measures differ between them and whether these measures relate differently to tear film quality.

Participants will:

• Answer a questionnaire about dry eye symptoms
• Have their visual correction measured (if they wear glasses)
• Undergo non-invasive assessments of tear film quality using an imaging device
• Complete three types of blink tasks, each repeated three times, including measurements of blinking and of tear film stability

Inclusion Criteria:

• Volunteer, fluent in French, willing to follow the protocol, able to read and understand the information sheet and provide free and informed consent
• Covered by a social security
• Aged between 18 and 65 years inclusive
• Binocular near visual acuity ≤ 0.3 LogMAR (≥ 5/10) (corrective glasses accepted)

Exclusion Criteria:

• Employees of Essilor International, Luxottica, or GrandVision and their subsidiaries
• Pregnant or breastfeeding women (Article L1121-5)
• Individuals deprived of liberty by judicial or administrative decision, or hospitalized without consent under Articles L.3212-1 and L.3213-1, who do not fall under Article L.1121-8, and individuals admitted to a health or social care facility for purposes other than research
• Adults unable or incapable of giving informed consent (Article L1121-8)
• Participants currently in an exclusion period from another study
• Participants deemed unfit to participate by the investigator for any reason that may affect subject safety or study integrity All categories of individuals particularly protected under French law are excluded from this research (Articles L1121-5 to L1121-9 of the French Public Health Code).
• Use of eye drops or ophthalmic solutions within the last 2 hours
• Wearing contact lenses within the last 48 hours
• Reported history of severe ocular pathology such as glaucoma, retinitis pigmentosa, diabetic retinopathy, macular involvement, resulting in visual field loss or acuity loss (especially aphakia), except for dry eye (which is not an exclusion criterion)
• Reported history of eye surgery or trauma to the eye or its adnexa excepted refractive surgery and cataract surgery
• Reported history of eyelid abnormalities (ptosis)
• Reported history of neurological deficits, including epilepsy or sensory-motor coordination disorders, vestibular or cerebellar pathology (e.g., balance disorders, nystagmus, Parkinson's disease)
• Reported history of musculoskeletal disorders preventing maintenance of a fixed head position