This is a single center, open label trial to evaluate Lifitegrast Ophthalmic Solution 5.0% in Dry Eye Disease using In Vivo Confocal Microscopy (IVCM

Approximately 30 subjects with dry eye disease (DED) will be treated with Xiidra® to evaluate the effects of lifitegrast on the ocular surface using in vivo confocal microscopy.

Inclusion Criteria:

• 1. Subject can read, understand and sign an informed consent letter. 2. Provision of signed and dated informed consent form and HIPAA authorization. 3. Stated willingness to comply with all study procedures and availability for the duration of the study 4. Male or female at least 18 years of age at the time of enrollment 5. Minimum corneal staining of ≥2 or greater according to the NEI grading scale in the lower corneal subregion.

Normal eyelids and corneal anatomy 7. For females of reproductive potential: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation and for an additional 4 weeks after the end of study drug administration 8.

For males of reproductive potential: should be able to agree to use at least 1 medically acceptable form of birth control with female partner (FOCBP) NOTE: Acceptable forms of birth control include:

• True abstinence (when this is in line with the preferred and usual lifestyle of the subject), or

• Vasectomy at least 3 months prior to the first dose of study drug

• Without a vasectomy, must use condoms with spermicidal foam, gel, film, cream, suppository at least 14 days prior to the first dose of investigational drug and throughout the study duration, and for 4 weeks after the last dose of the investigational drug.

• Or the female partner of the male investigational subject, must comply with the previous points.

9. Are postmenopausal (no menstrual cycle for at least one year prior to Visit 1) or have undergone bilateral tubal ligation, hysterectomy, hysterectomy with uni- or bilateral oophorectomy, or bilateral oophorectomy for 1 year prior to study start.

10. Best corrected visual acuity of 0.7 logMAR or better (Snellen equivalent score of 20/100 or better) in each eye at day -14 (Visit 1) and Day 0 (Visit 2) 11. Subject-reported history of dry eye for at least 6 months. 12. Schirmer Tear Test (without anesthesia) ≥1mm and ≤10mm at baseline 13. EDS score of ≥40 (0-100-point VAS, both eyes) value is an average at screening and baseline.

Exclusion Criteria:

• 1. Have a known hypersensitivity or contraindication to the product or their components.

Unwilling to discontinue contact lens use for the duration of the study 3. Pregnancy or lactation 4. Have used topical or nasal vasoconstrictors within 14 days prior to screening or unable to refrain from the same during study period 5. Subjects that use topical steroids, systemic immunosuppressive agents including oral corticosteroids, antihistamines, mast cell stabilizers or glaucoma medications.

6. Subjects unwilling to abstain from eyelash growth products containing prostaglandins for the duration of the trial.

7. Subjects who had ocular surgery within the past 1 year prior to Visit 1. 8. Febrile illness within one week. 9. Active or history of infectious keratitis; any other ocular infection within the last 30 days 10. Have serious or severe disease or uncontrolled medical condition that in the judgement of the investigator could confound study assessments or limit compliance.

11. Use of new prescription eyedrop within 30 days of screening 12. Change in systemic medication within 30 days of screening 13. Any subject who has previously tried and failed a course of lifitegrast. 14. Subjects with secondary Sjogren's syndrome (ex. Rheumatoid arthritis, systemic lupus, erythematosus) or other autoimmune disease (ex: multiple sclerosis, inflammatory bowel disease) are eligible for enrollment consideration provided the subject met all other inclusion and exclusion criteria, AND, were not in a medical state in the opinion of the principle investigator that could have interfered with the study parameters, were not taking systemic/ocular steroids and were not immunodeficient/immunosuppressed (ex: receiving systemic immunomodulating or immunosuppressive drugs to manage their baseline medical state.)