Non-invasive Tear Film Dynamic Measurements in Normal, MGD and ADDE Subjects After Saline Instillation

General Inclusion Criteria: * Good general Health * The subject must appear able and willing to adhere to the instructions set forth in this protocol (such as not use warm compresses or artificial tears/lubricant or excessive eye makeup before the visit on the study day). General Exclusion Criteria: * Ocular disease, infection or inflammation (allergy, blepharitis) that is clinically significant (grade 3 or 4) that in the opinion of the PI would not be a good subject. * Systemic disease or use of medication that in the opinion of the PI would not be a good subject. * Infectious diseases (e.g. hepatitis, tuberculosis) or an immuno-suppressive disease (e.g. HIV). * Contact lens wearer. * Pregnancy or lactation. * Diabetes. * Inclusion or exclusion criteria of the other cohorts. Cohort Specific Inclusion Criteria: * ADDE cohort: Schirmer I \< 10 mm, BUT ¬\< 5 seconds, Fluorescein 0 or 1, currently using an artificial tear for ocular comfort at least occasionally. * MGD cohort: Diagnosis of moderate or severe MGD * Normal/Control (Non Dry-Eye): meets general inclusion and exclusion criteria