Impaired vision and blindness are common. About 3.4 million people in the US are blind or visually impaired. Vision is usually measured by visual acuity charts, and normal vision is expressed as 20/20 ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. An inscription reads “SEITZ TEST ...

Wet age-related macular degeneration (AMD) happens when abnormal blood vessels leak fluid into the macula. It can cause wavy lines, blurriness, and dark spots, but not peripheral vision loss. The ...

Visual acuity -- the ability to discern letters, numbers, and objects from a distance -- is essential for tasks including recognizing a friend across a room and driving. Researchers previously assumed ...

Visual acuity—the ability to discern letters, numbers, and objects from a distance—is essential for many tasks, from recognizing a friend across a room to driving a car. Researchers previously assumed ...