For amblyopia masking treatment, the duration of the masking depends on the severity of the amblyopia and the age at which it is detected. If the amblyopia is detected at an early age, for example, before the child is 3 years old, and the visual acuity is not too low. This usually does not take too long, and the child may be completely normal by the time he or she is 5 or 6 years old. However, if the child’s amblyopia is detected late or is severe enough that it is not detected until the child is 7-8 years old, and the vision is particularly poor, even 0.1 or less. In this case, the masking time may be very long, until the child is a teenager, and the vision still has not returned to normal. Therefore, the duration of amblyopia masking must be decided according to the changes in the child’s visual acuity, and the masking should be stopped only after the child’s visual acuity has returned to normal.