Cornea Preservation Time Study

Study Participant Eligibility Criteria * Study Participant Inclusion Criteria 1. Age range 30-\<91 years with minimum life expectancy of at least 3 years. 2. Willingness to return for follow-up study visits at 1 day, 1 week, 1 month, 6 months, 1 year, 2 years and 3 years. 3. Fluent in English or Spanish. * Study Participant Exclusion Criteria 1) Decisionally and/or cognitively impaired Study Eye Eligibility Criteria * Study Eye Inclusion Criteria 1. Endothelial keratoplasty (EK) is scheduled between 10 and 60 days after enrollment * The 10-day requirement relates to the need to be able to randomly assign the eye to either intervention group. * The 60-day requirement relates to the need to have current eligibility and enrollment data at the time of surgery. If surgery is postponed to \>60 days after the initial enrollment visit, a new Baseline Visit and eligibility assessment will have to be performed. 2. Presence of a condition related to endothelial dysfunction which will be treated by EK. * Eligible indications for EK include: * Presence of Fuchs endothelial corneal dystrophy (FECD) meeting at least one of the following: * Phakic FECD * Phakic FECD with cataract * Triple procedure including EK for FECD, cataract extraction and posterior chamber intraocular lens implantation (IOL) is allowed * Aphakic FECD * Pseudophakic FECD with posterior capsule supported, suture-fixated, or sulcus-supported posterior chamber IOL * Aphakic or pseudophakic corneal edema with posterior capsule supported, suture-fixated, or sulcus-supported posterior chamber IOL without FECD * Study Eye Exclusion Criteria 1. Prior EK 2. Indication for surgery that is not suitable for EK (e.g, keratoconus, stromal dystrophies and scars) 3. Presence of a condition that has a very high probability for failure (e.g., failed EK or Penetrating Keratoplasty (PKP), heavily vascularized cornea, uncontrolled uveitis) 4. Other primary endothelial dysfunction conditions including posterior polymorphous corneal dystrophy and congenital hereditary corneal dystrophy 5. Anterior chamber IOL in study eye prior to or anticipated during EK 6. Planned intraocular lens exchange of an anterior chamber IOL with a posterior chamber IOL in study eye at time of study EK 7. Pre-operative central sub-epithelial or stromal scarring that the investigator believes is visually significant and could impact post-operative stromal clarity assessment 8. Stromal vascularization that is visually significant (by investigator's judgment) 9. Presence of anterior synechiae (iris to cornea) 10. Peripheral anterior synechiae (iris to angle) in the angle greater than a total of three clock hours 11. Hypotony (Intraocular pressure \<10 mm Hg) 12. Uncontrolled (defined as intraocular pressure \> 25mm Hg) glaucoma with or without prior filtering surgery or shunt or mini-shunt placement. * A shunt or mini-shunt is any device implanted to lower intraocular pressure through an external route (e.g Ahmed) or internal route (e.g. Glaukos) that is present in the anterior chamber angle or extends into the anterior chamber. 13. Controlled glaucoma with prior shunt or mini-shunt placement for glaucoma * Note: FECD or pseudophakic/aphakic corneal edema with posterior chamber IOL that also have undergone filtering surgery (without shunt or mini-shunt) in which glaucoma is currently considered under control will be eligible 14. Fellow eye visual acuity \< 20/200 that is not correctable with EK Eligibility Criteria for Second Study Eye 1. Study participant has already enrolled one eye 2. The second eye meets all study eye inclusion and exclusion criteria (2.2.2 and 2.2.3) 3. EK surgery in second eye is not planned within 6 weeks of EK on first study eye