Zero Dilation Ophthalmoscopy

Background: Digital imaging with a traditional nonmydriatic fundus camera (FC) is standard in diabetic retinopathy (DR) screening, but pharmacologic mydriasis, a time-consuming process, is recommended for patients with pupil diameter ≤3.3 mm. A zero-dilation confocal scanning laser ophthalmoscope (cSLO) has been developed for DR screening without pharmacologic mydriasis. Methods: This study compared clinical performance and ophthalmologist referral rates for the cSLO versus FC in a sample of 100 adult patients with diabetes. Kappa, and normalized sensitivity and specificity of each device, were calculated. Results: Because of incomplete datasets, 3 patients were excluded from analyses. For 33% of patients, pupil diameter was <3.3 mm after first image acquisition, due to pupil constriction caused by the intense flash. cSLO image acquisition took <3 minutes for 56% of patients. Overall, 28.9% of patients were recommended for referral by two expert graders. DR referral rates for the cSLO and FC showed strong agreement after device-blinded evaluation (percentage of agreement =88.6). Normalized sensitivity was 100% versus 85% for cSLO versus FC; normalized specificity was equivalent (96%). Conclusion: Compared with FC imaging, zero-dilation cSLO imaging showed improved sensitivity and equivalent specificity for detection of DR, and has the potential to improve efficiency of DR screening.