Variable Details

Available Studies

ROS, MAP, MARS, Clinical Core, LATC


Not Scaled

Variable Type 


Variable Name 




Visual acuity
Near-vision acuity based on Rosenbaum Pocket Vision Screener

Near-vision acuity is determined with the Rosenbaum Pocket Vision Screener (McCoy Health Science Supply, Maryland Heights, Mo., USA). Participants position the vision screener 14 inches from their eyes. With both eyes open and using corrective lenses, as needed, participants read the line of numbers indicative of 20/70 visual acuity. If participants are able to identify all numbers correctly, they are asked to proceed to the 20/50 line followed by 20/40 if all numbers at 20/50 visual acuity are defined correctly. If all numbers at 20/70 are not correctly identified, participants read the 20/100 line of numbers followed by the 20/200 and 20/400 lines, if necessary. Individuals are assigned a visual acuity associated with the last line read correctly which ranges from a best visual acuity of 1 =20/40 to the worst visual acuity of 7 = less than 20/400.

Value Coding
1 20/40
2 20/50
3 20/70
4 20/100
5 20/200
6 20/400
7 less than 20/400