Study of Brimonidine Tartrate Nanoemulsion Eye Drop Solution in the Treatment of Dry Eye Disease (DED)

Inclusion Criteria: 1. Aged 18 years or older. 2. Sign and date informed consent form approved by the IRB 3. History of Dry Eye Disease for ≥6 months 4. Demonstrate the following 2 signs of DED in the same eye at Screening and Baseline (Day 1): 1. Conjunctival staining at ≥3 (out of a possible score of 6 per eye), and 2. Schirmer test (with anesthesia) at ≥1 to ≤7mm in 5 minutes 5. Symptomatic evidence of DED by having a global symptom score (Overall SANDE) ≥40 mm at Screening and Baseline (Day 1) visit 6. Intraocular pressure (IOP) ≥ 5 mmHg and ≤22 mmHg in each eye 7. Women who satisfy one of the following: 8a. Are of child-bearing potential (WOCP) who are not pregnant or lactating and who are either abstinent or sexually active on an acceptable method of birth control for at least 4 weeks prior to Visit 1 and throughout the study (i.e., until Day 28), OR 8b. Are post-menopausal or have undergone a sterilization procedure Exclusion Criteria: 1. Allergic to brimonidine or any similar products, or excipients of brimonidine 2. Use of contact lenses within 14 days prior to Screening visit or planned use during study 3. Currently receiving brimonidine or other treatment for glaucoma or ocular hypertension or history of glaucoma surgery. 4. Receiving or have received any experimental or investigational drug or device within 30 days prior to Screening visit 5. Intraocular pressure \<5 mmHg or \>22 mmHg in either eye 6. Active ocular infection or history of ocular herpetic keratitis 7. History of neurotrophic keratitis or ocular neuropathic pain 8. Any history of eyelid surgery or intraocular/ocular surgery within the past 3 months 9. Punctal occlusion within 3 months prior to Screening visit or during study 10. Corneal epithelial defect larger than 1 mm2 in either eye 11. Have active drug/alcohol dependence or abuse history 12. Are neonates, pregnant/lactating women, children, or others who may be considered vulnerable populations 13. Received corticosteroid-containing eye drops within 14 days prior to Screening visit or planned use during study 14. Any change in systemic corticosteroids/immunosuppressives, cyclosporine ophthalmic emulsion 0.05% (Restasis®), cyclosporine ophthalmic solution 0.09% (Cequa™), or lifitegrast ophthalmic solution 5% (Xiidra®) within 30 days prior to Screening visit or planned change during study 15. In the opinion of Investigator or Study Coordinator, be unwilling or unable to comply with study protocol or unable to successfully instill eye drops 16. Disease, condition, or disorder that in the judgement of Investigator could confound study assessments or limit compliance to study protocol