Author: Rita Serras-Pereira (Portugal)
Co-authors: Luísa Vieira, Christopher J. Saunders, Ricardo Figueiredo, Rita Anjos, Margarida Marques, Rita Flores
Purpose
Virtually all orbital and ocular structures can be affected by microvascular occlusions in patients with sickle cell disease (SCD) but the major cause of vision loss in these patients is proliferative sickle cell retinopathy (PSR). Clinical presentation is often unremarkable until late stages where vitreous hemorrhage or retinal detachment lead to a reduction in visual acuity. The purpose of this study was to identify systemic and/or ophthalmologic predictors of PSR in the population studied in order to better stratify patients and define a screening strategy that privileges patients at higher risk of developing ophthalmological complications.
Setting/Venue
Ophthalmology Department, Centro Hospitalar Universitário de Lisboa Central, Lisbon, Portugal.
Methods
Cross-sectional study in which 45 patients with SCD were included. Patients received a complete ophthalmologic evaluation including Optical Coherence Tomography (OCT), OCT-Angiography (OCTA) and Fluorescein Angiography (FA). Using en-face OCT images and an image binarization software (ImageJ ®), total choroidal area (TCA) and luminal area (LA) were obtained, and choroidal vascular index (CVI) was calculated as the proportion of LA to TCA. Additionally, OCTA en-face images of the superficial and deep capillary plexuses were evaluated and number of vessels, vascular density and lacunarity were calculated using Angiotool ® software.
Results
Forty-five eyes from 45 patients (21 male, 24 female) with electrophoretic confirmation of SCD were included in the study. Patients’ mean age was 38.2 ± 12.2 years. Sickle cell genotypes included 36 patients with SS (80%), 5 patients with SC (11.1%) and 3 patients with S-Thal (6.7%). The majority of patients (n=38, 84.4%) had best corrected visual acuity of 1.0 at presentation. Based on FA imaging and according to Goldberg’s retinopathy classification, 86.7% of patients were diagnosed with sickle cell retinopathy, 69.2% (n=27) with non-proliferative retinopathy (NPSR) and 30.8% (n=12) with PSR. Mean corpuscular volume (MCV), lactate dehydrogenase (LDH) and percentage of fetal hemoglobin (HbF) were inferior in the subgroup of patients with PSR when compared with patients with non-PSR (p<0.001; p= 0.04; p= 0.007, respectively). The best predictor of PSR was MCV (ROC curve = 0.842; p=0.001). With a cut-off of 79.75 fL, sensitivity and specificity for the presence of PSR were 86.7% and 83.3%, respectively. The authors did not identify statistically significant differences between patients with PSR and non-PSR in any other systemic or ophthalmologic parameters studied, including in the quantitative analysis of the retinal vascularization using OCTA and choroidal vascularization using OCT (p>0.05).
Conlusions
Sickle cell retinopathy is a very common complication of SCD. According to our results, the incidence of SCR can be as high as 86.7% when assessed by fundoscopy and FA imaging. A significant number of patients with high-risk disease were asymptomatic at presentation and only identified in the setting of a mass screening program. Mean corpuscular volume was the best predictor of proliferative sickle retinopathy with a sensitivity and specificity of 86.7% and 83.3%, respectively, when a cut-off of 79.75 fL was used.
Financial Disclosure
None.
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