Spectral-domain optical coherence tomography characteristics in patients with transfusion-dependent thalassemia

Patients with transfusion-dependent thalassemia (TDT) are at risk of neuroretinal changes due to chronic anemia, hypoxia, iron overload, and chelation therapy. This study aims to compare central macular thickness (CMT), macular ganglion cell layer thickness (GCL), and peripapillary retinal nerve fiber layer (RNFL) measured using spectral-domain optical coherence tomography (SD-OCT) in TDT patients with controls.

This is a cross-sectional study of 170 eyes of 85 TDT patients between 5 and 30 years and 170 eyes of 85 controls with similar age ranges and sex distribution. Demographic characteristics, systemic characteristics, and SD-OCT-measured CMT, GCL thickness, and global and quadrant-wise peripapillary RNFL thickness were recorded.

There were 52 (61.2%) male and 33 (38.8%) female cases and 36 (42.4%) male and 49 (57.6%) female controls. The median age of TDT patients was 18 years (range: 6-30 years), while that of the controls was 21 years (range: 7-28 years). The mean GCL ( P = 0.002) and global ( P = 0.008), inferior ( P = 0.013), temporal ( P = 0.016), and nasal ( P = 0.023) RNFLs were thicker in controls than in TDT patients. There was no difference in CMT ( P = 0.495) and superior RNFL ( P = 0.303) between TDT patients and controls.

While no significant differences were observed in CMT or superior RNFL between the two groups, controls demonstrated greater GCL and RNFL thickness in three quadrants compared to TDT patients. These findings suggest the possibility of subtle neuroretinal alterations in TDT that may not yet be clinically evident. Larger longitudinal studies are recommended to validate these findings.