Retinal and Choroidal Changes in Transthyretin-Related Amyloidosis Using Optical Coherence Tomography Modalities: A Systematic Review

Introduction: Optical coherence tomography (OCT) and OCT angiography (OCT-A) are valuable tools for detecting retinal and choroidal changes in systemic diseases. This systematic review evaluates the current evidence on retinal and choroidal alterations associated with transthyretin-related amyloidosis (ATTR). Methods: A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines across PubMed, Scopus, Web of Science, and Embase up to December 2024 to investigate structural and microvascular alterations in the retina and choroid of patients with genetically confirmed ATTR, aiming to evaluate their potential as imaging biomarkers for disease monitoring. Results: Nine eligible studies were identified, encompassing a total of 246 individuals, including both symptomatic patients and pre-symptomatic carriers. Reported findings included thinning of the outer nuclear layer (ONL), reduced vessel density in the superficial and deep capillary plexuses, enlargement of the foveal avascular zone (FAZ), and a decreased choroidal vascularity index (CVI). Conclusions: Thinning of ONL was the most consistent structural finding, suggesting photoreceptor degeneration. Decreased CVI, reduced vascular density, and enlargement of the FAZ further indicate impaired vascular integrity. Although OCT and OCT-A show promise for early detection and monitoring of ocular involvement in ATTR, most studies were case–control studies with small sample sizes and possible confounding from ongoing treatments. These limitations highlight the need for standardized imaging protocols and longitudinal studies to confirm findings and clarify the link between ocular and systemic disease severity.