Sickle Cell Retinopathy Structural and Vascular Changes Identified With OCT

Optical coherence tomography angiography (OCT-A) may identify microvascular changes in pediatric patients with sickle cell retinopathy, according to a paper presented at the American Society of Retina Specialists meeting, held in Seattle, July 28 to August 1, 2023.  

Researcher Sandra Hoyek, MD, a postdoctoral research fellow at Harvard Medical School’s Massachusetts Eye and Ear Infirmary, compared macular thickness and microvascular changes among pediatric patients with sickle cell disease.

The retrospective, consecutive series analyzed 606 eyes of 303 patients with sickle cell disease (53.1% girls) who presented to Boston Children’s Hospital between 1998 and August 2022. Study participants underwent retinal thickness assessment using macular optical coherence tomography (OCT), and measurements of superficial capillary plexus (SCP) vessel density (VD), deep capillary plexus (DCP) VD, and foveal avascular zone (FAZ) area using OCT-A scans.

A total of 46% of patients inherited sickle cell genes from both parents (HbSS; n=280), 18% inherited a sickle gene from one parent and a hemoglobin C gene disease from the other (HbSC; n=106), 8% had HbS thalassemia (n=50), 25% had sickle trait (n=154), and the patient’s genotype was unknown in 3% (n=16) of eyes. 

A total of 35.6% of patients presented with temporal retinal thinning at baseline and 60.6% of patients had it at their last visit. Among individuals with temporal retinal thinning, 5.4% and 9.5% did not have peripheral sickle cell retinopathy  at baseline and at the study conclusion, respectively. 

Eyes with HbSS were more likely to demonstrate macular thinning compared with eyes with HbSC at presentation (56.8% vs 29.7%; P <.001) and final visit (63.5% vs 30.2%; P <.001), the presentation shows. OCT analysis indicated eyes with HbSS had thinner retinal thickness compared with HbSC eyes and HbS thalassemia (P ≤.01).

Peripheral sickle cell retinopathy was associated with larger FAZ area at presentation (P =.0003) and lower DCP VD at final visit in the superior nasal (P =.012) and inferior temporal (P =.017) macular quadrants.

Participants’ SPC VD, DCP VD, and FAZ area did not vary with genotype.

“Temporal retinal thinning in the macula was observed in eyes without peripheral [sickle cell retinopathy], suggesting the importance of adding OCT macular thickness as a diagnostic criterion for [sickle cell retinopathy],” according to the paper. “Eyes with peripheral SCR had lower macular DCP VD and larger FAZ compared to eyes without peripheral SCR, highlighting that OCTA may help in early identification of [sickle cell retinopathy].”