More than 4000, but you may not be satisfied with correcting your vision. After surgery, you may feel that the degree of correction is insufficient, not as good as expected, or over-corrected, and hyperopia, that is, presbyopia, may be advanced. There will be dry eye, which may hurt the tear film nerve during the operation and reduce the secretion of tears. Glare and night vision impairment may also occur. It is suggested that two cups of Zheng Jiuwei Pupil Tea every day can clear the liver and improve eyesight, dredge meridians and activate collaterals, and accelerate the metabolism of ocular capillaries.