A Double-Masked, Randomized, Placebo-Controlled, Parallel-Group, 12-Week Administration With Two-Week Gradual Dose Taper Phase and 38-Week Follow-Up Phase, Phase 3 Study to Investigate the Safety and Efficacy of Ripasudil (K-321) Eye Drops After Descemetorhexis in Subjects with Fuchs Endothelial Corneal Dystrophy

Pre-DSO Criteria Each subject who is planning to undergo DSO must meet all of the following criteria to be enrolled in the study: 1. Is at least 18 years old at the screening visit (Visit 1) 2. Has a diagnosis of FECD at Visit 1 3. Has confluent central guttae in the study eye that can be removed by descemetorhexis of a circular area of 5.5 mm diameter or less (at Visit 1) 1) 4. Has either of the following visual impairments: a. Study eye with BCVA of 78 letters or fewer by ETDRS testing (Snellen equivalent of 20/32 or worse) at Visit 1, or b. Study eye with BCVA of greater than 78 letters by ETDRS testing and who have self-reported glare disability, or a reduction in vision due to a stray light (scattered light from a bright source, or self-reported difficulty with contrast sensitivity at Visit 1. 5. Can understand the written informed consent, provides signed and witnessed written informed consent, and agrees to comply with protocol requirements before any study-specific assessments are performed Post-DSO Criteria 6. The study eye descemetorhexis at Visit 2 is confirmed to have excised a central area with confluent guttae and a diameter of 4.5 to 5.5 mm

Is a female subject of childbearing potential and any of the following is true: a. is pregnant or lactating/breastfeeding, or b. is not surgically sterile, not post-menopausal (no menses for the previous 12 months), or not practicing an effective method of birth control as determined by the Investigator (eg, oral contraceptives, double barrier methods, hormonal injectable or implanted contraceptives, tubal ligation, or partner with vasectomy) 2. Has a study eye with confluent guttae in the periphery or confluent guttae outside the stripped area (individual guttae are allowed) after descemetorhexis 3. Has a study eye with baseline (pre-DSO) peripheral ECD ungradable for any area (nasal, temporal, superior, and inferior) due to any reason other than a medical reason (eg, guttae, corneal edema, or striae) 4. Has a study eye with a history of cataract surgery within 90 days of Visit 1 5. Has a study eye with a history of any previous intraocular surgery other than for cataract prior to Visit 1 6. Has a non-study eye with a history of any previous intraocular surgery within 30 days of Visit 1 7. Plans to receive any surgical treatment on the study eye, other than the study descemetorhexis, during the duration of the study 8. Plans to receive any surgical treatment for FECD or cataract on the non-study eye during either the screening or treatment period 9. Has advanced corneal stromal edema, which is defined as the presence of widespread haze or bullae on slit lamp examination at Visits 1 and 2 10. Has a study eye with central corneal thickness ≥670 μm at Visit 1 11. Has known severe comorbidities that may interfere with descemetorhexis (including but not limited to a bacterial, viral, or fungal ophthalmic infection) 12. Has any clinically significant ocular condition, other than FECD, cataract, primary open-angle glaucoma* or dry eye in the study eye that requires medication or ocular surgery 13. Has diabetes with poor blood sugar control, defined as hemoglobin A1c (HbA1c) value >8.5% at Visit 1

Has diabetes with poor blood sugar control, defined as hemoglobin A1c (HbA1c) value >8.5% at Visit 1 14. Has used either collagen shield or contact lenses in the study eye within 7 days of Visit 1 15. Is unwilling to stop use of either collagen shield or contact lenses in the study eye for the duration of the study 16. Has hypersensitivity to any ophthalmic medication used for diagnosis or treatment, including eye drops containing antibiotic(s) or glucocorticoid(s) 17. Has known hypersensitivity to any component of the study drugs 18. Has previously used ripasudil 19. Has used netarsudil or eye drops and ointments containing ≥2% sodium chloride within 14 days prior to Visit 1 20. Has participated in any investigational drug or device clinical studies within 30 days of Visit 1 or is planning to participate in any investigational drug or device clinical studies during the study period 21. Has a positive urine test result for drugs of abuse (opiates, methadone, cocaine, amphetamines, barbiturates, or benzodiazepines) or alcohol at screening; however, drugs prescribed to treat current medical conditions are allowed 22. Is a member or a family member of the professional or ancillary personnel working at the study site or the Sponsor involved in the study 23. Has a concomitant medical or psychological condition that could interfere with study participation or is otherwise not suitable for entry into the study in the opinion of the Investigator 24. Is using any prohibited prescription or over-the-counter (OTC) medications or devices and is unwilling or unable to discontinue these medications or devices for the required time period before entry into the study 25. Is committed to an institution by virtue of an order issued either by the judicial or the administrative authorities. 26. Has any ocular disease that may affect visual acuity in the study eye, such as glaucoma that has progressed to the central visual field, age-related macular degeneration, diabetic macular edema, amblyopia, etc