The function of the lens meter is to measure the vertex power and prism power of the lens, determine the optical center and axial position of the lens, and check whether the lens is correctly placed in the frame.

The lens meter plays an important role in the preparation process of glasses. If the measurement of the lens meter is inaccurate, the prepared glasses will seriously fail to meet the standard. Not only can it not correct vision and protect vision, but even endanger vision health.

Therefore, the focal meter must be subject to mandatory verification according to national regulations to ensure accurate and reliable measurement.

Solutions to problems with the focal meter ：

1. When starting the lens meter, the lens meter usually performs a self-test. The machine will check whether the light path is smooth and there is no foreign object blocking it. If the screen displays an error or cannot enter the system normally after starting up, first check whether the lens cover of the measuring lens is open. The above error will also occur if the lens is placed on the lens holder first and then turned on.

2. When the optical path of the lens meter is unblocked, after booting into the system, it is found that the lens meter cannot be reset to zero. There are several reasons for the above situation:

① Due to the long-term work of the lens meter, the working environment has an impact on the optical path system, such as dust accumulation on the support. At this point, just take off the measurement base cap, wipe the cover glass with a clean silicon cloth or lens paper, and put it back.

②The optical components above the lens dot structure of the lens meter are more likely to be stained with oil and dust during use, and can be wiped clean with a cotton ball dipped in a small amount of alcohol.

3. There is a difference in the indication value of the focal meter

① The wear of the lens measurement base causes the standard position to deviate, resulting in an out-of-tolerance indication. The wear of the measuring base has a serious impact on the data measurement of the instrument, especially when measuring the altimeter lens, the error is very large. And there is no linear relationship between the affected measurement data changes. If the wear is slight, it can be improved by attaching the anti-wear gasket to the lens base. If the wear is serious, the entire base can only be replaced.

②Part of the lens meter has the function of measuring ordinary lenses and contact lenses. They need to be replaced with different caps for detection. If the wrong cap is used during detection, the data will be out of tolerance. So check your lenses to see if you are using the correct cap.

③Focimeter is sensitive to strong light environment, so try to keep the indoor light soft when inspecting the lens. If the light is too strong, the reading will be unstable, and it will not be easy to align with the optical center, resulting in out-of-tolerance phenomenon of the test point. If the above situation occurs, it can be solved by adjusting the position of the lens meter or using low-light or no-light lighting.