Features： 1、Red Green Color Glass: Through wearing glasses to observe the four dot light, can have separation of two eyes, to determine whether there is visual fusion dysfunction in the two eyes. 2、Ophthalmology Use: Used in clinical tests for ocular depression and amblyopia, and 4 dot test light can determine the type of color vision impairment. 3、Accurate Detection Data: Color is pure and complementary, can completely filtered to avoid detection bias, thus the detection data is accurate with small bias. 4、Portable and Lightweight: When hold test torch, will not tired your hands. With the manual and USB charging cable, which is easy to use, simple operation. 5、ABS Material: Penlight ophthalmic tester is high hardness, scratch resistance, corrosion resistance, high temperature resistance, will not easily damaged, can be used for a long time. Specification： Item Type: 4 Dot Red Green Light Glasses Material: ABS Built in Battery: Lithium ion battery 2000mAH Product Function: 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. 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 Light 1 x Glasses 1 x Left Red Glasses Clip 1 x Instruction Manual 1 x USB Charging Cable