Macular microvascular alterations in adults with sickle cell anemia detected by optical coherence tomography angiography
Year: 2025
Type: article
Study design: Observational Study
Abstract: • Sickle cell (SC) anemia is an inherited hemoglobinopathy characterized by the substitution of valine for glutamic acid at the sixth position of the β-globin chain, resulting in the formation of hemoglobin S (HbS). These sickled cells contribute to microvascular occlusion, chronic hemolysis, and end-organ ischemia. • OCTA is a novel, non-invasive imaging technique that visualizes the retinal microvasculature without the need for dye injection. • All participants had best-corrected visual acuity of 20/20, normal intraocular pressure, and no funduscopically detectable abnormalities. • The DCP is particularly susceptible to ischemic changes in SC anemia, while changes in the SCP may vary. • Enlargement and irregularity of the foveal avascular zone (FAZ) are increasingly being recognized as sensitive markers of microvascular damage in SC anemia. • The pathophysiology behind the DCP's vulnerability lies in its anatomical position and perfusion dynamics, being supplied by terminal capillaries and thus highly sensitive to hypoxia and occlusive insults. • Limitations of the current study include the relatively small sample size and its cross-sectional design, which precludes analysis of disease progression. To evaluate macular vascular density (VD) and foveal avascular zone (FAZ) alterations in adult patients with sickle cell (SC) anemia without clinical signs of retinopathy using optical coherence tomography angiography (OCTA), and to compare these findings with healthy controls. In this cross-sectional, comparative study, 18 right eyes from 18 adult patients with SC anemia and 25 right eyes from age- and sex-matched healthy individuals were analyzed. Those with SC disease were group 1 and healthy controls were group 2. All participants had normal fundus examination findings. OCTA imaging (RTVue-XR Avanti; Optovue Inc.) was used to measure vascular densities in the superficial capillary plexus (SCP) and deep capillary plexus (DCP), as well as FAZ dimensions, using a 3 × 3 mm macular scan. Vascular density measurements were compared across eight macular sectors. Image quality below 8/10 was excluded. The mean age of group 1 was 24.73±6.60, group 2 was 23.70±3.19 ( p = 0.572). The female/male ratio was 10/8 in group 1 and 12/13 in group 2 ( p = 0.500). DCP vascular density was significantly reduced in all sectors in the SC anemia group compared to controls ( p < 0.001). SCP vascular density was significantly lower only in the temporal region ( p = 0.015). Superficial FAZ was significantly enlarged in SC anemia patients (0.45 ± 0.09 mm²) compared to controls (0.33 ± 0.07 mm², p = 0.001), while deep FAZ did not show a statistically significant difference ( p = 0.145). Sickle cell anemia is associated with substantial microvascular compromise in the deep retinal capillary plexus, even in the absence of clinical retinopathy. OCTA proves to be a sensitive, non-invasive imaging modality capable of detecting subclinical vascular changes. Early identification of these alterations may aid in the prevention of vision-threatening complications in SC anemia.
Institutions: Harran University, Dicle University
Language: English
Subfield: Genetics
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,610
OpenAlex ID: W4413099801