- 水泠泠Lv 52 decades agoFavorite Answer
BC:8.8 -> 表示矯正後最佳視力敏銳度
BVCA (best corrected visual acuity) The best possible vision a person can achieve with corrective lenses measured in terms of Snellen lines on an eye chart. Contact lenses frequently achieve 20/15 vision, superior resolution to most surgeries and eyeglasses.
A measurement of the refractive power of a lens element, as a portion of a meter. If a camera lens is focused on infinity, and a +1 diopter accessory lens is attached to the front, the camera will now have sharp focus at 1 meter, even though the barrel of the lens is still set to infinity.
If a +1/2 diopter is used, the focus is shifted to 2 meters.
If a +1/4 diopter is used, the focus is shifted to 4 meters.
If a +2 diopter is used, the focus is shifted to 1/2 meter.
If a +3 diopter is used, the focus is shifted to 1/3 meter.