The use of retinal wide-field imaging system to screen for sickle cell retinopathy (SCR)

Abstract

Purpose : To investigate the use of wide-field retinal imaging for the diagnosis and screening of SCR.

Methods : Design: Prospective blinded observational case series. Participants: Our study includes 2 arms: Adults, more than 18 years of age, and pediatrics, five to 18 years of age. The adult arm included 160 eyes of 80 Participants. The pediatric arm included 108 eyes of 54 participants. Three main sickle cell types were included: Sickle cell SS, Sickle cell SC, Sickle Cell /β Thalassemia. Methods: After obtaining an informed consent, participants underwent a standard clinical fundus exam by an attending retina staff or a clinical retina fellow. On the same day, a color fundus photo was obtained for each eye using the Optos 200TX wide-field imaging system. Using the Goldberg classification scheme SCR was classified into 4 main categories: No SCR, non-proliferative SCR, proliferative SCR without neovascularization (early proliferative SCR) and proliferative SCR with neovascularization. Two blinded graders analyzed the images for SCR presence and staging. A combined score for the clinical fundus exam and the wide-field image analysis findings were recorded for each subject. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the wide-field imaging system and of the clinical fundus exam to identify and stage SCR were calculated.

Results : The median age was 29 years for the adult arm (range 18-69 years), and 14 years for the pediatric arm (range 7-17 years). There was a substantial inter-observer agreement in analyzing the wide field images (weighted kappa = 0.749; 95% CI 0.614-0.885). The prevalence of SCR was 33.3% in the pediatrics arm (n=108 eyes) and 63.1% in the adults arm (n=160 eyes). As a screening tool to detect the presence of any SCR, the wide field imaging system had a sensitivity of 80.6% in the pediatrics groups and 82.2% in the adult group. The wide-field imaging system was also sensitive to detect any sea-fan neovascularization (sensitivity: 80% in the pediatrics group and 83.9% in the adult group). Among the pediatrics participants the wide-field imaging system had higher sensitivity than clinical fundus exam to detect early proliferative sickle cell retinopathy 86.7% and 46.7% respectively.

Conclusions : The wide-field retinal imaging is a very sensitive tool to screen for SCR. It is fast, accurate and well tolerated by participants.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.