Nonmydriatic ultrawide field retinal imaging system and nonmydriatic two-field digital fundus photography system in a large-scale diabetic retinopathy screening

Abstract

Objective To compare the consistency and difference of nonmydriatic ultrawide field retinal imaging system versus nonmydriatic 2-field 45°digital fundus photography system in a large-scale diabetic retinopathy (DR) screening. Methods A total of 733 with type 2 diabetic patients (1466 eyes) underwent nonmydriatic ultrawide field retinal imaging and nonmydriatic 2-field 45°digital fundus photography examination. Two independent readers graded images respectively to determine the stage of DR. A third masked retinal specialist adjudicated discrepancies. Using nonmydriatic 2-field 45°digital fundus photography examination as the standard, the consistency of nonmydriatic ultrawide field retinal imaging was evaluated. The statistic index included sensitivity, specificity, Youden index and Kappa value. The difference of two methods was analyzed by comparative t-test. Results Based on nonmydriatic ultrawide field retinal imaging, the results were as follows: non DR (NDR) in 1062 eyes (74.1%), DR in 340 eyes (23.7%), ungradable in 32 eyes (2.2%). Among 340 DR eyes, there were mild nonproliferative DR (NPDR) in 48 eyes, moderate NPDR in 216 eyes, severe NPDR in 57 eyes, proliferative DR (PDR) in 19 eyes. Based on nonmydriatic 2-field 45°digital fundus photography, the results were as follows: NDR in 1080 eyes (75.3%), DR in 270 eyes (18.8%), ungradable in 84 eyes (5.6%). Among 270 DR eyes, there were NPDR in 36 eyes, moderate NPDR in 175 eyes, severe NPDR in 53 eyes, PDR in 6 eyes. Compared with nonmydriatic 2-field 45°digital fundus photography for screening DR, the sensitivity was 98.0%, the specificity was 95.0%, and the kappa value was 0.87. For screening severe NPDR and PDR, the sensitivity was 100.0%, the specificity was 99.0%, and the kappa value was 0.94. The DR detection rate and the ratio of the picture can't interpretation between two methods both had significant difference (P=0.00). Conclusions In rapid large-scale DR screening, there is high consistency between nonmydriatic ultrawide field retinal imaging versus nonmydriatic 2-field 45°digital fundus photography. Nonmydriatic ultrawide field retinal imaging is proved to be more adaptive, and more comprehensive and precise. Key words: Diabetic retinopathy/diagnosis; Fluorescein angiography