Bangerter masking films consist of a series of graded and graduated films that are used to compensate for the stereoscopic contrast of the dominant eye to the amblyopic eye. The masking film can be cut to the same shape and size as the frame eyeglass lenses and is simply applied to the inside of the eyeglass lenses with water. Applications Preventive applications: Prevention of amblyopia, suppression, and retinal abnormalities correspond. Therapeutic applications: treatment of amblyopia, visual axis correction, diplopia, lens-free monocular diplopia (<0.1). Can be used for primary treatment or as an alternative treatment when complete masking treatment can no longer improve. Product specifications are 0.0, LP, <0.1, ~0.1, ~0.2, ~0.3, ~0.4, ~0.6, ~0.8, ~1.0 in 10 sizes. For example, if the visual acuity of the amblyopic eye of a patient is 0.4 and the visual acuity of the dominant eye is 0.6, a 0.2 mask should be selected to cover the dominant eye according to the principle of suppressing the dominant eye by 2 lines. Note: When the visual acuity of the healthy eye is below 1.0, the visual acuity of the healthy eye can be suppressed 2 lines lower than the visual acuity of the amblyopic eye; when the visual acuity of the healthy eye is higher than 1.0, the visual acuity of the healthy eye can be suppressed 3~4 lines lower than the visual acuity of the amblyopic eye. Visual acuity grade masking film serial number visual acuity 1.0~20/200.8~20/250.6~20/300.4~20/500.3~20/700.2~20/1000.1~20/200<0.1~20/300 light perception no 00 no.