Each batted ball is assigned an xBA based on how often comparable balls -- in terms of exit velocity, launch angle and, on certain types of batted balls, Sprint Speed -- have become hits since Statcast was implemented Major League wide in 2015. (As of January 2019, xBA now factors in a batter's seasonal Sprint Speed on "topped" or weakly hit" balls).
The eye care specialist will then use a headlight and a special lens to perform the exam. Depending on the nature of your findings, the doctor may also examine your retina while exerting a slight amount of pressure around your eye (scleral depression). In general, no imaging tests are necessary to diagnose this disease, although some providers may obtain wide-angle photographs of your retinas to assist in monitoring your condition. 2b1af7f3a8