Combined wide-field imaging in grading diabetic retinopathy

Objectives: To detect retinal neovascularization elsewhere (NVE), of the optic disc (NVD) and intraretinal microvascular abnormalities (IRMA) in treatment naive diabetic retinopathy (DR) and compare these findings by using 90° Wide-Field Colour Fundus Photography (WF CFP), Wide-Field Spectral-Domain Optical Coherence Tomography Angiography (OCTA) and the combination of WF CFP and OCTA through overlay software. Methods: Patients with treatment naive severe non-proliferative DR or proliferative DR were prospectively enrolled. All patients underwent WF-CFP and OCTA in the same day. Two readers independently analysed WF-CFP, SD-OCTA and the overlay of the two techniques. The degree of agreement between the two raters and between different techniques (WF CFP, OCTA, WF CFP combined to OCTA) were measured with Cohen's Kappa coefficient. Results: Thirty-one eyes from 21 patients (10 males, mean age 63 ± 15 years) were included. Inter-rater agreement by using WF-CFP in detection of NVE, NVD and IRMA was respectively 0.62, 0.22 and 0.55. OCTA scored values of inter-rater agreement of 0.86, 0.87 and 0.92 in detection of NVE, NVD and IRMA, respectively. By combining WF-CFP and SD-OCTA, inter-rater agreement in detection of NVE, NVD and IRMA was 0.93, 0.94 and 0.89, respectively. Conclusion: Inter-rater agreement in detection of NVE, NVD and IRMA was substantial, fair and moderate, respectively. OCTA provided almost perfect values of inter-rater agreement in NVE, NVD and IRMA detection. Combining WF-CFP and OCTA further empowered concordance values in detection of NVE and NVD. Combining OCTA and WF-CFP is the best performance to detect NVE and NVD.