ADD precautions
① Empirical formula method: ADD = (age - 30) / 10
② Near vision method: ADD = near vision - distance vision
③ FCC precision method: ADD = 1/2 (NRA + PRA) + FCC
FCC: binocular fusion cross cylinder test
NRA/PRA: binocular positive and negative relative accommodation measurement.
Of course, the results of measuring ADD are not the end, we still need to pay attention to some small details:
① According to the patient's near reading needs, use a ruler to mark the habitual working distance (33cm or 40cm)
② For patients with weak eye downward rotation ability, the ADD can be appropriately increased
③ In principle, the ADD of both eyes should be kept consistent as much as possible. In special cases, try not to exceed +0.50
④ In principle, if the ADD value is between +1.75-+2.00DS, the comfort is the best.
When the ADD value is higher than +2.00DS, everyone must be careful, and the patient needs some time to adapt.
If the ADD value is higher than +3.00, the success rate will decrease, the comfort level will be poor, and the adaptation period will be long.
⑤ When the ADD is relatively large, you can choose a long-channel progressive lens.
⑥ When the patient mainly uses it near, in principle, the ADD should be appropriately increased by +0.25DS
we will attend the 2024 Beijing Optical Fair on Sep.10~Sep.12, welcome to our booth. You can know our products first, please check which items you are interested in and contact us freely. Now Summer is coming, Our photochromic lenses are hot sale , please find more details form our website. we also have RX preceitpion lens and so on.
Post time: Jun-07-2024