1 Complete covering is also called full day covering. The daily covering time accounts for 70%~100% of the non sleep time, so the healthy eyes are covered for about 10~14 hours every day.

Direct covering: the oldest and most popular visual rehabilitation method for amblyopia, complete opaque covering. Direct covering has several beneficial physiological effects: forcing patients to practice monocular eye movement skills such as fixation, tracking, scanning and adjustment; The amblyopic eye can obtain appropriate sensory stimulation so that the cortical perceptual area can be developed; Masking is helpful to break the inhibition mode related to anisometropia and strabismus amblyopia; Covering in strabismus amblyopia can prevent the occurrence or development of abnormal retinal correspondence.

In order to prevent masked amblyopia in healthy eyes, the ratio of covering/removing covering or alternating covering of both eyes can be formulated according to the difference of binocular vision and the age of children. The ratio is roughly as follows:

The more tight the mask is, the better the effect will be. When the eye mask is used on the glasses, the light can still enter the eyes from the periphery of the lens. Moreover, many children are used to taking off the eye mask, which can not achieve the effect of covering. In this case, the eye patch can be directly applied to the eyes. If the vision of both eyes becomes the same or the vision still does not progress after 3 months of normal continuous covering, the covering can be stopped gradually.

2Indirect covering (reverse covering).

Incomplete covering is also called partial covering. If the covering time is less than 70% of the non sleep time, it is partial covering, and partial covering is at least 2 hours a day. During follow-up, adjust the covering time according to the covering effect.

Infants are more sensitive to covering, usually covering for part of the time. When starting to cover, you can start from a small amount. At the time of follow-up, you can adjust the cover time at any time by observing the effect. For children over 3 years old, the longer they use amblyopia, the faster their vision recovers, and the shorter their treatment period. With the growth of age, school-age children need to be covered for a longer time every day, often all day. But in consideration of children's learning, we can use our spare time to cover our healthy eyes and open our eyes during class.