Study of Retinal and Choroidal Changes in Children with Sickle Cell Disease using Optical Coherence Tomography and Angiography

Abstract

Background Sickle cell disease is known to cause vaso-occlusive peripheral retinopathy as a result of the microvascular insults that occur when sickled erythrocytes affect the retinal and choroidal blood flow. This leads to non-proliferative retinopathy (NPR) and proliferative retinopathy (PR) that can result in vision affection. While sickle cell retinopathy (SCR) in adult patients is well described, less is known about the retinal changes that occur in pediatric patients. To date, most studies have been of adults. Objective To screen children with sickle cell disease for the presence of retinal and choroidal changes and to compare the findings with age and sex matched controls by performing structural SD-OCT and OCTA and to correlate between findings. This aimed to assess the prevalence and age of onset of retinopathy among pediatric patients. Patients and Methods This cross sectional study was carried out from February 2020 to August 2020 on 30 eyes of patients attending outpatient clinic of Ophthalmology and Pediatric Departments of Ain Shams University Hospitals. Those patients were asked to participate and were enrolled in this study. The ethical standards stated by the ethical committee of Ain Shams University Hospitals were followed. Informed written consent was taken from guardians of all participants. Results There was a significant difference between the cases and control groups regarding the SCP and DCP vessel density, FAZ area, vascular disc density, central macular thickness, choroidal thickness, RNFL average thickness, IS/OS and C/D vertical ratio. However, there was no significant difference between the cases two groups regarding the GCC. There was a significant positive correlation between the retinal thickness and the vessel density in the SCP and DCP in the corresponding subfields. There was a positive statistically significant correlation between the Hb F level and the vessel density of the SCP and DCP. Also, there was a negative statistically significant correlation between the Hb F level and the FAZ. There was a negative statistically significant correlation between the Hb S level and the choroidal thickness, GCC and RNFL average thickness. There was also a statistically significant negative correlation between the disease duration and the temporal parafoveal retinal thickness. Conclusion SD-OCT and OCTA were able to detect areas of thinning and decreased vascular densities in asymptomatic sickle cell children. This study demonstrated a decreased vessel density on OCTA but a normal retinal thickness on SD-OCT in some of the parafoveal sucfields. This suggests that OCTA can detect microvascular abnormalities and retinopathy early even before it is visible on OCT. Further longitudinal studies are needed to examine the vascular densities and retinal and choroidal thinning in sickle cell disease children and their correlation with the various disease parameters.

Temporal macular thinning and vessel density correlation in children and young adults with sickle cell disease

“…Even though fluorescein angiography (FA) remains the gold standard, difficulty in children collaboration and the need for a fluorescein dye make it a less appealing option in the follow up of this population. Also, there have been studies that show that OCTA is more sensitive than FA in detecting macular microangiopathy in asymptomatic patients and that it can detect microvascular abnormalities and retinopathy even before it is visible on OCT. 6,7 Several studies have shown that OCTA detects vascular abnormalities in adult patients with sickle cell disease, but the pediatric population remains less studied. 5,[8][9][10][11] This study aims to evaluate the correlation between VD in OCTA and temporal macular thinning in OCT in children and young adults with SCD, proving that it is the microvascular insults that cause chronic ischemic changes of the inner retinal layers resulting in a temporal macular thinning in the OCT.…”

“…Even though fluorescein angiography (FA) remains the gold standard, difficulty in children collaboration and the need for a fluorescein dye make it a less appealing option in the follow up of this population. Also, there have been studies that show that OCTA is more sensitive than FA in detecting macular microangiopathy in asymptomatic patients and that it can detect microvascular abnormalities and retinopathy even before it is visible on OCT. 6,7…”