A Study to Evaluate Corneal Endothelial Cell Density (ECD) in Subjects With Dry Eye Disease (DED) Administering Miebo® (Perfluorohexyloctane Ophthalmic Solution) for 12 Months.

Inclusion Criteria:

1. Be at least 18 years of age at the time of consent.

2. Have a self-reported history of DED in both eyes (OU) for at least 6 months prior toVisit 1 (Screening/Baseline)

3. Have a total corneal fluorescein staining score (tCFS) score >2 in both eyes

4. Have an Ocular Surface Disease Index (OSDI) score >17

5. Have a baseline ECD ≥1750 cells/mm2 in each eye

6. Provide written informed consent

7. Be able and willing to follow instructions, including participation in all trialassessments and visits

8. If a contact lens wearer, be willing to discontinue contact lens use during and for 30 minutes following instillation of investigational drug and during study visits

Exclusion Criteria:

1. Be at least 18 years of age at the time of consent.

2. Have a self-reported history of DED in both eyes (OU) for at least 6 months prior toVisit 1 (Screening/Baseline)

3. Have a total corneal fluorescein staining score (tCFS) score >2 in both eyes

4. Have an Ocular Surface Disease Index (OSDI) score >17

5. Have a baseline ECD ≥1750 cells/mm2 in each eye

6. Provide written informed consent

7. Be able and willing to follow instructions, including participation in all trialassessments and visits

8. If a contact lens wearer, be willing to discontinue contact lens use during and for 30 minutes following instillation of investigational drug and during study visits

9. Have any clinically significant ocular surface slit lamp findings and/or in theopinion of the Investigator have any findings that may interfere with trialparameters in either eye

10. Have an ocular or periocular malignancy in either eye

11. Have a history of herpetic keratitis in either eye

12. Have any planned ocular and/or lid surgeries in either eye during the course of thestudy

13. Have a known allergy and/or sensitivity to the IP

14. Have a history of ocular laser surgery in either eye within 3 months (90 days) priorto Visit 1 (Screening/Baseline)

15. Have a history of incisional ocular surgery or severe trauma in either eye within 3months (90 days) prior to Visit 1 (Screening/Baseline)

16. Have high contrast best-corrected visual acuity equal to or worse than logMAR +0.7 (Snellen equivalent score of 20/100 or worse) as assessed by Early TreatmentDiabetic Retinopathy Study (ETDRS) scale in either eye, obtained under bright roomlighting

17. Be a woman who is pregnant, nursing or planning a pregnancy during the course of thestudy

18. Be a woman of childbearing potential who is unwilling to submit to a urine pregnancytest. Non-childbearing potential is defined as a woman who is permanently sterilized (eg, has had a hysterectomy or bilateral tubal ligation or bilateral oophorectomy)or is postmenopausal (without menses for 12 consecutive months).

19. Be a woman of childbearing potential who is not using an acceptable method of birthcontrol. Acceptable methods of contraception include hormonal - oral, implantable,injectable, or transdermal - contraceptives; mechanical contraception - spermicidein conjunction with a barrier such as a diaphragm or condom; intrauterine device; orsurgical sterilization of partner. For non-sexually active females, abstinence maybe regarded as an adequate method of birth control; however, the subject must agreeto use adequate birth control as defined above for the remainder of the study if shebecomes sexually active during the trial.

20. Be currently enrolled in an investigational drug or device trial or plan to enrollduring the course of the study

21. Have a condition or be in a situation that the Investigator believes may put thesubject at significant risk, may confound the study results, or may interferesignificantly with the subject's participation in the study