Feature: 1. Avoid Deviation: 4 dot glasses has pure red and green colors, which can be completely filtered and complement red and green, effectively avoiding detection deviation. 2. Flashlight Handle: The flashlight in this set of optometry tools has an anti slip design, which is easy to hold and not easy to slip off when using. 3. Main Function: For the clinical examination of visual suppression and amblyopia, it can determine the type of color vision disorder of the patient. 4. Storage Case: With a portable storage box, you can organize and store your accessories, so you can easily carry them around. 5. Excellent Material: Made of hard material, lightweight and virtually unbreakable. Include the red green glasses, and instructions manual. Specification: Item Type: 4 Dot Red Green Light Glasses Material: ABS Battery: 3 x Battery (not include) Product Function: 1. Wearing red and green glasses to observe the four dot light, the use of color complementarity of this situation, the separation of the two eyes. 2. To determine whether there is visual fusion dysfunction in the two eyes in the case of separation of monocular inhibition at the same time.. Package List: 1 x Four Dot Light1 x Glasses 1 x Storage Box 1 x Instruction Manual Note: 1. The flashlight usually has four holes on the surface, about 0.4in in diameter. they will be organized into a rhombus shape. The holes are arranged in such a way that the top hole shows only red light, the left and right show only green light, and the bottom hole shows white light.2. When looking at the flashlight with red and green glasses, a patient with normal vision in both eyes will see the four holes directly. If the patient has suppressed eyes, he will see two or three holes. If the eye does not have a fused image, the patient will see five holes (if the eye sees two white holes two separate, then two holes are not fused).3. The white holes are also used to test the primary eye. If the two eyes can fuse the images, the color of the white holes seen by the patient during the test is the color of the primary eye.4. To avoid suppression of the red and green glasses, the red and green can be examined interchangeably.