Comparisons of Handheld Retinal Imaging with Optical Coherence Tomography for the Identification of Macular Pathology in Patients with Diabetes

Introduction: Handheld retinal imaging cameras are relatively inexpensive and highly portable devices that have the potential to significantly expand diabetic retinopathy (DR) screening, allowing a much broader population to be evaluated. However, it is essential to evaluate if these devices can accurately identify vision-threatening macular diseases if DR screening programs will rely on these instruments. Thus, the purpose of this study was to evaluate the detection of diabetic macular pathology using monoscopic macula centered images using mydriatic handheld retinal imaging compared with spectral domain optical coherence tomography (SDOCT). Methods: Mydriatic 40°-60° macula centered images taken with 3 handheld retinal imaging devices [Aurora (AU), Smartscope (SS), Retinavue 700 (RV)] were compared with the Cirrus 6000 SDOCT taken during the same visit. Images were evaluated for presence of diabetic macular edema (DME) on monoscopic fundus photographs adapted from Early Treatment Diabetic Retinopathy Study (ETDRS) definitions [no DME, noncenter-involved DME (non-ciDME) and center-involved DME (ciDME)]. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for each device with SDOCT as gold standard. Results: Severity by ETDRS photos: No DR 33.3%, mild NPDR 20.4%, moderate 14.2%, severe 11.6%, proliferative 20.4%, ungradable for DR 0%; no DME 83.1%, non-ciDME 4.9%, ciDME 12.0%, ungradable for DME 0%. Gradable images by SDOCT (N=217, 96.4%) showed no DME in 75.6%, non-ciDME in 9.8%, ciDME in 11.1%. Ungradable rate for images (poor visualization in >50% of the macula), was AU:0.9%, SS:4.4%, RV:6.2%. For DME, sensitivity and specificity was similar across devices (0.5 – 0.64, 0.93 – 0.97). For nondiabetic macular pathology (ERM, pigment epithelial detachment, traction retinal detachment) across all devices, sensitivity was low to moderate (0.2 – 0.5) but highly specific (0.93 – 1.00). Conclusions: Compared to SDOCT, handheld macular imaging attained high specificity but low sensitivity in identifying macular pathology. This suggests the importance of SDOCT evaluation for patients suspected to have DME on fundus photography, leading to more appropriate referral refinement.