1. The surface of the flashlight is usually with four holes, approximately 1cm in diameter. They would be organized in a diamond shape. Traditionally, the holes are arranged with the top hole showing only red light, the left and right holes showing only green light and the bottom hole showing white lighting.
2. Watch the flashlight with red and green glasses, a patient with normal binocular vision will appreciate four holes. If the patient has suppression of the eyes, he will see two or three holes. If two eyes do not fuse the images, the patient will see five holes (The eyes see two white holes separately and two holes are not fused).
3. The white hole is also used to test the dominant eye. If two eyes can fuse the images, the color of the white hole seen by the patient during the test, is the color of the dominant eye.
4. In order to avoid the suppression of the red and green glasses, the red and green glasses can be exchanged for checking.
1. LED Bulbs
2. Power: AAA batteries 1.5V*3
3. Dimension: 5.4*11CM
4. Weight: 0.2KG