Retinal hypoxia, ischemia, and neovascularization may develop after microvascular occlusion seen in patients with sickle cell disease. Neovascularization that occurs before the development of vitreous hemorrhage or retinal detachment is the most important precursor .
In different studies, retinal disorders such as retinal pigment epithelial degeneration and mottling, peripheral and central retinal thinning, venous tortuosity, retinal hemorrhage, retinal edema, cup-to-disk ratio enlargement and macular scarring have been reported in beta-thalassemia patients. The prevalence of reported retinal disorders differs between studies .
The main aim of this study is to evaluate the retinal changes that may occur in patients with hemoglobinopathy with OCT-A. There are statistically significant differences in angiography parameters between patients with hemoglobinopathy and healthy controls.
Lynch et al, included fifty-two patients with SCR (33 non-proliferative and 19 proliferative) and 20 healthy controls in their study. FAZ perimeter and acircularity index were significantly higher in SCR eyes compared to controls. In addition, vessel density in SCR eyes was significantly lower than in the control group .
Zhou et al included 31 patients with SCR (21 NP-SCR and 10 P-SCR) and 14 healthy controls in their study. All FAZ (area, perimeter, acircularity) measurements were significantly higher in NP-SCR and P-SCR subjects than in healthy controls .
Han et al., in their study including 82 eyes of 46 patients, found that there was a loss of flow and a decrease in vessel density in patients with sickle cell retinopathy .
In a study published in 2018, 36 eyes of 19 patients were evaluated. The mean ischemic index was found to be higher in patients with sickle SC (8,0%) than in patients with sickle SS (3,2%; p = 0.01). The ischemic index was also higher in patients with proliferative sickle cell retinopathy (9,3%) than in those without (2,8%; p < 0.01) .
This is the largest study using OCT-A imaging in patients with beta-thalassemia and sickle cell disease reported in the literature. However, by using different imaging devices, the accuracy of imaging protocols that have not yet been standardized can be increased.
In conclusion, it was determined that all FAZ parameters (area, circularity, perimeter) were significantly different in patients with both beta-thalassemia and sickle cell disease, even if retinopathy was not clinically developed. In addition, vessel and perfusion density were found to be lower in both patient groups compared to healthy controls. However, no significant correlation was found between the severity of retinopathy of the patients and angiography parameters. In addition, a correlation was observed between hemoglobin levels and angiography parameters in patients with beta-thalassemia major.