Phase 1/2 Open-Label Dose-Escalation Study to Evaluate Safety of a Single Intravitreal Injection of RTx-021 in Patients With Stargardt Disease

Inclusion Criteria: * Male and female patients \>= 16 years of age * Able to comply with the study visit schedule and all protocol assessments * Diagnosis of Stargardt Disease (genetic testing required) * Study eye and fellow eye Best Corrected Visual Acuity meeting study criteria * Presence of retinal ganglion cells and/or retinal nerve fiber layer on Spectral Domain Optical Coherence Tomography testing at Screening confirmed by central image reading center * Adequate organ function and general good health Exclusion Criteria: * Participation in a clinical study (ocular or non-ocular) with an investigational drug, agent, or therapy in the past six months * Concurrent participation in another interventional clinical ocular study * Prior receipt of any gene therapy (ocular or other), retinal implant, or ocular cell therapy * Pre-existing eye conditions in either eye that would preclude the planned treatment or are significant enough to interfere with the interpretation of study endpoints or procedural complications * Known steroid responders if their intraocular pressure was not able to be managed effectively with topical pressure-lowering medications after prior use of steroid medications * Complicating systemic diseases including those in which the disease itself, or the treatment of the disease, can alter ocular and/or central nervous system function (e.g. radiation treatment of the orbit; leukemia with optic nerve involvement) * Any immunological response dysfunction including, immuno-compromising diseases or use of immunosuppressive medications, among others * Cataract or other ocular (including refractive) surgery, intraocular and/or peri-ocular injection in either eye within the prior four months (i.e. 120 days) prior to screening * Prior vitrectomy or aphakia in the study eye * Known sensitivity to any component of the study treatment or contraindication to medications planned for use in the peri-procedural period (e.g. povidone-iodine to prep for intravitreal injection) * Known contraindication to prophylactic steroid regimen * Current pregnancy or breastfeeding * Any other condition that would not allow the patient to complete follow-up examinations during the study