Iron-associated central macular ganglion cell complex thinning and choroidal vascularity index elevation in...

This study aimed to evaluate alterations in macular microstructure and blood flow density in patients with transfusion-dependent β-thalassemia (TDT) using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA), and to explore their associations with markers of iron metabolism.

A cross-sectional study was conducted involving 31 TDT patients (61 eyes) and 31 age- and sex-matched healthy controls (61 eyes) at the Affiliated Hospital of Guangdong Medical University from October 2022 to December 2023. Data collected included basic information, medical history, best-corrected visual acuity, ocular biometry, fundus photography, and OCT/OCTA imaging. Parameters assessed comprised the thickness and blood flow density of individual macular layers, as well as choroidal stromal area, choroidal luminal area, and choroidal vascular index (CVI). Pearson correlation analysis was employed to examine relationships among macular parameters, serum ferritin (SF) levels, duration of iron chelation therapy (ICT), and other variables.

Compared to healthy controls, TDT patients exhibited significant thinning of the central macular area ganglion cell layer, retinal nerve fiber layer, and ganglion cell complex (mGCC), accompanied by increased blood flow density in the deep vascular complex, nerve fiber layer vascular plexus, and deep capillary plexus (all P < 0.05). The choroidal stromal area was reduced (P = 0.037), whereas CVI was elevated (P = 0.034). Pearson correlation analysis revealed a positive correlation between central mGCC thickness and the duration of ICT (r = 0.280, P < 0.05),and a significant positive correlation between CVI with SF levels (r = 0.426, P < 0.01). Stepwise linear regression analysis identified the duration of ICT (β = 0.306, P = 0.011) as a significant independent factor influencing central mGCC thickness. Similarly, SF levels significantly influenced CVI (β = 0.469, P < 0.001). Additionally, 62.30% of TDT patients' eyes presented with tilted optic discs, 34.43% showed tessellated fundus, and 6.56% had pseudoxanthoma elasticum.

TDT patients exhibit both macular neuroretinal thinning and increased microvascular blood flow density. CVI and central mGCC thickness may serve as potential biomarkers for monitoring iron-related ocular pathology and therapeutic efficacy. Future longitudinal studies are warranted to validate their predictive value and establish causality. Regular ocular screening is warranted in this population.