The Jaeger eye chart is a small, handheld card used to test a patient's near vision, according to AllAboutVision.com. The chart consists of short sections of different-sized text, ranging from J1 to J11 or larger, with J2 being the equivalent of 20/20 vision.
Doctors use the Jaeger chart in two different ways, notes AllAboutVision.com. A doctor may hold the chart at a specific distance from a patient's eyes and ask him to read the passage with the smallest type size he can see. Another way to use the chart is to move it forward and back until the patient can read a specific type size.