What are the eye chart? Is the eye chart the same? _Industry News_
It is an indispensable part to test vision with eyeglasses with glasses. There are many types of vision charts, such as international standard vision charts, including E-shaped vision charts, C-shaped vision charts, and astigmatism charts. People don't ask whether they are all the same, or do they have different functions. The editor will answer them in detail below! The E-shaped eye chart is the most common visual standard in China. To judge the patient's visual function, most of the projector's E-shaped vision chart is a standard logarithmic vision chart. The decimal visual acuity recording range is: 0.1, 0.16, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, 2.0. The C-shaped vision chart is also called the open ring vision chart. It is more popular abroad. It uses eight directions to judge the patient's vision function. Most projectors have such vision charts, but they are rarely used in my country. This visual chart is too difficult to identify, and there is no confidence in the refractive power, but C-shaped visual acuity can more accurately reflect the visual acuity state, and the definition of visual acuity standard is very precise. More in line with the vision requirements of the human eye. The visual acuity recording range of the C-shaped eye chart in the projector is: 0.05, 0.1, 0.16, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, 2.0. Digital optotypes or English optotypes, children optotypes, it is mainly to facilitate patients to see their own vision, to facilitate the exchange and communication between patients and optometrists, use voice to answer, and judge the vision based on whether the answer is correct or not. state. However, this method is not very standard, and there will be certain errors in visual judgment. Astigmatism meter astigmatism: Astigmatism meter astigmatism is also known as hand watch, bell watch, radiometer and solar watch, etc., mainly to test whether the patient has astigmatism. Red and green optometry: It is mainly to test the degree of the ball eye, and the monocular test is mainly used. Left is red, right is green. If the red is clear, a negative spherical mirror should be added, and if the green is clear, a positive spherical mirror should be added. Polarized red and green optometry: It is mainly used to test the correction of the power of the binocular lens. It must be used with the aid of a comprehensive refractometer. Polarized red and green optotypes are also commonly used in binocular vision balance tests and strabismus tests. Astigmatism target: also known as speckle removal method, mainly to test the correction of spherical lens power. It is a kind of whether the point of view is clear, mainly based on the monocular test.