A Study to Learn How Stargardt-type Eye Conditions Progress in Children and Adults

Inclusion Criteria: * Participant has a documented clinical diagnosis of macular dystrophy expressing a STGD-type clinical presentation and molecular confirmation, defined as either: * ABCA4-associated disease: presence of biallelic (pathogenic or likely pathogenic) ABCA4 variants, or one definite disease-causing ABCA4 variant together with a typical phenotype consistent with STGD. * STGD-like macular dystrophy: presence of one or more pathogenic variants in a gene known to cause macular dystrophy, as appropriate for its expected inheritance mode. Note: All genetic testing should be performed by a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory or equivalent whenever possible. Acceptable documentation includes a copy of the genetic test report, laboratory certification statement, or clinical notes explicitly referencing CLIA certification. Predicted pathogenic variant of uncertain significance (VUS) that cannot be confirmed by standard laboratory criteria as certainly disease-causing (novel mutations) will be considered on a case by-case basis. * Participant has sufficiently clear ocular media and adequate pupillary dilation to allow for all imaging procedures. * Participant has intraocular pressure (IOP) both at screening and baseline of ≤ 21 mmHg measured by applanation tonometry. Note: Participant who is on topical IOP lowering treatment may also be included. * Participant has a spherical equivalent refractive error between + 8.00 D and - 10.00 D. Eyes with high myopia (\> -10.00 D) are permitted only if there are no signs of myopic degenerative macular changes. * Participant has a BCVA ranging from 20/500 to 20/40 (equivalent to 15 to 70 ETDRS letters read at 1 meter) * For participants in the \> 20/80 to ≤ 20/40 BCVA range (moderate visual impairment \[MVI\]): presence of a visible definite or probable residual EZ on spectral-domain optical coherence tomography (SD-OCT) (no minimum residue size required) and a total retinal SD-OCT central subfield retinal thickness ≥ 150 µm * For participants in the ≥ 20/500 to ≤ 20/80 BCVA range (SVI): presence of a residual outer nuclear layer (ONL) within the macular SD-OCT scan area and measurable within the Age-Related Eye Disease Study (AREDS) grading grid and no residual EZ or minimal thickness of the ONL required * Participant has evidence of retinal pigment epithelium (RPE) disease/damage on SD-OCT (hypertransmission defects \[HTDs\]) and/or FAF imaging. * Participant has evidence of at least questionably decreased autofluorescence (QDAF) (incomplete retinal pigment epithelial and outer retinal atrophy \[iRORA\]), defined as mottled or speckled hypo-autofluorescence (AF) signal, mixed with or without hyper- AF, on FAF imaging. Note: At study onset, having patches of definitely decreased autofluorescence (DDAF) within the FAF image and/or patches of complete retinal pigment epithelial and outer retinal atrophy (cRORA) on SD-OCT ≥ 250 µm will not be a requirement for participation but will be acceptable for inclusion, so long as: * DDAF/cRORA areas are contained within the limits of the AREDS grading grid (≤ 12 disc areas), and physically distinct and separate from other areas of QDAF, DDAF and/or hyper-AF that may be present outside the AREDS grading grid, and * the other BCVA and SD-OCT required inclusion criteria are also met. * Participant is able to comply with the protocol and willing to undertake all scheduled visits and assessments during the total study period. * Participant is deemed capable of performing reliably all tests required for participation. Exclusion Criteria: * Participant has a known history of significant systemic disease (e.g., uncontrolled hepatitis, pancreatitis, cirrhosis, liver failure, uncontrolled thyroid disease or immunocompromising conditions such as human immunodeficiency virus \[HIV\]) that could impact ocular health or confound study assessments, based on medical history or prior clinical documentation. * Participant has an autoimmune condition that requires treatment with immunomodulatory therapy and/or biologics that cause immunosuppression. * Participant has a known diagnosis of diabetes mellitus with a documented hemoglobin A1c (HbA1c) value ≥ 7% 3 months prior to screening and based on available medical records. If the documented HbA1c is ≥ 7% and there is no clinical history of diabetic symptoms, diabetic retinopathy, abnormal renal function (e.g., elevated creatinine), or glycosuria noted in medical records, the participant may be enrolled. * Participant has a known history of any systemic or metabolic condition, or physical examination finding that may significantly affect ocular health or interfere with the interpretation of study assessments. * Participant has a history or evidence of severe cardiac disease (e.g., New York Heart Association Functional Class III or IV), clinical evidence of unstable angina, acute coronary syndrome, myocardial infarction or revascularization within 6 months prior to screening. * Participant has a history or evidence of ventricular tachyarrhythmia requiring ongoing treatment. * Participant has a significant cardiovascular or cerebrovascular disease, including a history of stroke within 12 months prior to screening. * Participant has any complicating systemic disease or active malignancy. Squamous cell carcinomas will be an exclusionary criterion if lesions are recurrent and/or \> 2 cm in diameter and/or affect the lip or ear area. Basal cell carcinomas are permitted, provided they are not located in the immediate periocular facial region. A history of any prior malignancy is allowed if the treating physician or oncologist confirms that the participant has been free of recurrence or metastasis for at least 5 years prior to screening. * Participant has another known or suspected molecular diagnosis of macular or retinal disease (e.g., pathogenic mutations in other genes) that could confound interpretation of study outcomes, ind