 In this study, we will deploy annular-array systems and assess their experimental and clinical utility for ophthalmic imaging. We hypothesize that a 20-MHz annular array will detect posterior vitreous detachment PVD more reliably than a conventional single element ultrasound system. Clinically, we will test the hypothesis that 20-MHz annular arrays improve detection of PVD, an important risk factor for disease progression in diabetic retinopathy. Diabetic retinopathy is the leading cause of blindness in the working population 25 to 65 years and the third major cause of legal blindness in the U.S. 