The tool - about the size of a hand-held video camera - scans a patient's entire retina in seconds and could aid primary care physicians in the early detection of a host of retinal diseases including diabetic retinopathy, glaucoma and macular degeneration. Researchers at the Massachusetts Institute of Technology (MIT) describe their new ophthalmic-screening instrument in a paper published in the open-access journal Biomedical Optics Express, published by The Optical Society (OSA).