1, lens transmittance and optical uniformity test method: hand-held lenses from the eyes about 30 centimeters, from the lens to observe the distance.
If the vision is clear, no deformation, and slow movement without jumping, indicating that the lens transparency and optical uniformity is better. 2, Optical Center location test method: On the white paper with a large cross, strokes should be clear and straight. Hand-held lenses, with one eye from the lens to observe the shape of the cross stroke. If the mirror outside the mirror is not a line, can move the lens, so that the cross strokes inside the lens and the mirror outside the link into a gleam. A small point in the center of a cross that is observed in the lens with a soft pen, which is the optical center. Two lenses point out the optical center, the two sides of the optical center to compare the symmetry, and then use a ruler to measure the distance between the two center points is consistent with the prescribed pupil distance.
If the cross stroke in the lens is curved, the quality problem of the lens is indicated.