The essence of severe amblyopia is that the visual cells are in a state of inhibitory sleep or stunted atrophy, i.e. sleeping and atrophied, due to certain congenital causes such as congenital cataract, strabismus, nystagmus or high myopia and high hyperopia, high binocular refractive error, etc. Second, the basic principle of treating severe amblyopia: remove the cause, wake up the sleeping cells with special color light, and use threshold icons to exercise the atrophied vision. Third, a variety of therapeutic instruments to improve the low ability to increase the principle of vision: 1, the function of attracting attention: the most important, if the child can not look at the icon or color light for a longer period of time, any vision-enhancing work may fail due to the lack of a certain amount of visual stimulation. Attention-attracting features include: (1) closed head and eye shield such as Dr. Eye 3-5 generation instrument and eye shield low vision amblyopia treatment instrument, etc. In this type of equipment, the child is training icons or color light in front of the eye, darkness around the eye, can effectively prevent things around the distraction; (2) moving, zoom icons or color light: changing targets than static targets more attractive to children’s attention. (3) colors and patterns of interest to children, etc.: Wolffy, Pleasant Goat, cats, dogs, 3D stereograms, etc. The docked hood, flying dots, bifocal flying dots and color light pursuit in Dr. Eye 3-5 amblyopia devices are all attention-getting vision enhancement functions. 2, threshold icon vision enhancement function: is the most effective direct vision enhancement function, “threshold” is the threshold, that is, the child can just see clearly but there is a certain difficulty of the threshold, over this hurdle, vision will improve. (1) Threshold “E” or “C” icons: for children over 3 or 5 years old, see Dr. Eye 3-5 generation amblyopia device (2) Threshold grating visual physiology, icons: for children under 2 or 5 years old, non-cooperative children, see Dr. Eye eye patch type low vision amblyopia device (3) Threshold image icons: for children under 2 or 5 years old, see Dr. Eye patch type low vision amblyopia device (3) Threshold image icon: suitable for children aged 2, 5 and 3, 5 years old, who can read images. It can wake up the sensitivity of three types of RGB vision cells in the retina of the fundus, and indirectly increase vision, such as the RGB color light enhancement in Dr. Eye amblyopia apparatus; 4, RGB eye sensitivity enhancement: use RGB color light to wake up the sleeping vision cells, and use the color light position change to train focus sensitivity.