ST266 Eye Drops for the Treatment of Persistent Corneal Epithelial Defects

Inclusion Criteria: * Male and female subjects aged 18 years and over. * Subjects with a PED present for at least seven (7) days. * The defect may be of any size and must be measurable by slit lamp. * In the Investigator's opinion, the defect is persistent i.e., the defect has not shown improvement despite conventional treatment such as tear supplements and bandage contact lenses. * The original defect to the cornea must be the result of any injury, infection, disease or surgery to the eye. Exclusion Criteria: * Subjects currently being treated with cenegermin. * Subjects who require treatment with autologous serum eyedrops throughout the duration of the trial. If, in the opinion of the investigator, autologous serum eyedrop treatment can be safely stopped, the subject may be included in the clinical trial. * Subjects who require treatment with other amnion products throughout the duration of the trial. If, in the opinion of the investigator, the amniotic product treatment can be safely stopped, the subject may be included in the clinical trial. * Subject who requires treatment with amniotic membrane throughout the duration of the trial. If the amniotic membrane can be safely stopped, the subject may be included in the clinical trial. Note: The amniotic membrane must be removed at least one (1) day prior to the baseline visit. * Subjects who require treatment with bandage contact lens that cannot be removed at least 24 hours prior to screening. If the bandage contact lens can be safely removed, the subject may be included in the clinical trial. * Subject with an uncontrolled lid or ocular infection. * History of alkali burns of the cornea. * The circumference affected by limbal blood vessel ischemia is greater than 75 percent of the circumference. * Subjects with severe lid abnormalities contributory to the persistence of the PED such as the inability to close the lids. * Subjects who have a history of AIDS or HIV. * Treatment with systemic corticosteroids (equivalent to \>10 mg/day of prednisone) or immunosuppressive (including Plaquenil) or chemotherapeutic agents within 7 days prior to Day 1, or likely to receive one of these therapies during study participation. * Subjects who have participated in a clinical trial within 30 days prior to Day 1. * Subjects who have more than one distinct PED in the study eye prior to screening visits. Subjects who develop PEDs after the screening visit will remain in the study; however, only the original study PED will be assessed. * Subjects with bullous keratopathy. * Subjects with corneal perforation or impending corneal perforation. * For subjects with bilateral PEDs, only the eye with the larger PED should be entered in to the study. The non-study eye will receive standard of care treatment and will be observed throughout the trial. * Female subjects who are pregnant or breastfeeding. Female subjects who are neither postmenopausal nor surgically sterile require a negative urine pregnancy test on Day 1 visit. * Epithelial defect was classified as a progressive corneal melt caused by an immunological process such as rheumatoid melt or Mooren's ulceration. * Subjects with recurrent corneal erosion.