Session Title: Free Paper Session 21: Imaging III
Session Date/Time: Sunday 10/09/2017 | 08:00-09:30
Paper Time: 08:00
Venue: Room 113
First Author: : T.Alabduljalil KUWAIT
Co Author(s): : C. Cheung C. VandenHoven L. MacKeen M. Kirby P. Kertes W. Lam
To investigate the use of ultra-wide field retinal imaging (UWFI) for the diagnosis and screening of sickle cell retinopathy (SCR)
Prospective masked observational case series. Subjects participation took place at Toronto western hospital and SickKids Hospital, University of Toronto, Canada.
Our study included 2 arms: Adults (more than 18 years of age; n=268 eyes) and paediatrics (5 to 18 years of age; n=168 eyes). Three main sickle cell types were included: Sickle cell SS, SC and Sickle Cell /β Thalassemia. After obtaining an informed consent, participants underwent a standard clinical fundus exam using slit-lamp biomicroscopy and indirect ophthalmoscopy. On the same day, a colour fundus photograph was taken for each eye using the Optos 200TX UWFI. Using the Goldberg classification SCR was classified into 4 main categories: No SCR, non-proliferative SCR (non-PSCR), capillary occlusion and anastomosis (early PSCR) and proliferative SCR with neovascularization (PSCR). Two masked graders analyzed the images and graded the level of SCR. Inter-grader agreement was calculated using Pearson (r) correlation coefficient. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the UWFI and of the clinical fundus exam were calculated compared to gold standard test. Combined score was determined for each eye based on the collective findings of its CFE, grader 1 and grader 2 image analysis. This combined score was only used to determine the prevalence of SCR in our cohort.
The mean age was 30.8 years for the adult arm (range 18-69 years), and 12.67 years for the paediatric arm (range 6-17 years). There was good inter-grader agreement in both groups, the highest agreement between CFE, grader 1 and grader 2 was in detecting PSCR. Using the combined score, the prevalence of any SCR was 38.1% in the paediatric arm (n=168 eyes) and 60.4% in the adult arm (n=268 eyes). When the gold standard test was presumed to be CFE the UWFI analysis by grader 1 had a sensitivity of 75% in the paediatrics groups and 83.67% in the adult group to detect the presence of any SCR. For detecting PSCR, the UWFI as interpreted by grader 1 had a sensitivity of 80% in the paediatrics group and 87.1% in the adult group. The UWFI as interpreted by each grader identified twice as many cases with early PSCR than CFE.
The UWFI is a very sensitive tool to screen for sickle cell retinopathy. It is superior to CFE in detecting capillary occlusion and anastomosis. The UWFI is fast, accurate and well tolerated by participants.