Letter charts are not only used to measure visual acuity, they are also used as targets for subjective refraction. This is the main reason distance acuity is measured more often than near acuity. At a long distance, accommodation is relaxed, so that the refraction can be more accurate.
Popliteal artery. The popliteal artery branches off from the femoral artery. It is located in the knee and the back of the leg. Its courses near the adductor canal and the adductor hiatus, distinctive open areas inside the thigh. At its far end, it splits into the anterior and posterior tibial arteries. During its course, the popliteal artery branches into other significant blood vessels.
Medical Malpractice, failure to diagnose injury to the popliteal artery. By Anthony H. Gair, Gair Gair Conason Steigman Mackauf Bloom&Rubinowitz. The popliteal artery is the major source of blood supply to the lower leg. The femoral artery becomes the popliteal artery as it passes through the hiatus of the adductor magnus muscle and enters the popliteal fossa.