Purpose: The purpose was to evaluate retinal vascular parameters by optical coherence tomography angiography in β-thalassemia major patients.
Methods: Thirty-three patients with β-thalassemia major (study group) and 29 healthy children (control group) were enrolled in the study. All subjects underwent a complete ocular examination. The mean foveal avascular zone, non-flow area, foveal avascular zone perimeter, acircularity index of foveal avascular zone, foveal density, the superficial capillary plexus, and deep capillary plexus were scanned using 6 × 6 mm optical coherence tomography angiography scans centered on the macula. Superficial capillary plexus and deep capillary plexus were also scanned centered on the optic disk. We collected data on histories of patients, and hemoglobin and ferritin were also studied from both groups.
Results: The mean age was 13.85 ± 4.69 years (range: 4-21 years) in β-thalassemia major group and 12.59 ± 3.66 years (range: 6-18 years) in the control group. The mean foveal avascular zone value was 0.265 ± 0.11 mm2 in the study group and 0.296 ± 0.12 mm2 in the control group. The mean non-flow area value was 0.468 ± 0.12 mm2 in the study group and 0.479 ± 0.14 mm2 in the control group (p > 0.05). Differences in the mean values for foveal density and acircularity index were statistically significant between the study group and control group (p < 0.05, p = 0.026, and p = 0.026, respectively). Superficial capillary plexus and deep capillary plexus were not a significant difference between the study and control groups in 6 × 6 mm scans on macula and 4.5 × 4.5 mm scans on optic disk area (p > 0.05). Acircularity index was negatively correlated (r = -0.292, p = 0.026), and foveal density was positively correlated with hemoglobin (r = 0.292, p = 0.026).
Conclusion: By using optical coherence tomography angiography, we detected foveal microvascular changes in young β-thalassemia patients before significant ocular anomalies development.
Keywords: deep capillary plexus; foveal density; optical coherence tomography angiography; peripapillary retinal capillary density; superficial capillary plexus; β-thalassemia major.