Focimeter measuring equipment is used to measure the top power of eyeglass lenses, determine the axis direction of astigmatic lenses, and print a mark on the optical center of the lenses. Incorrect or non-standard operation by operators will directly affect the accuracy of measurement, resulting in unqualified glasses. The correct use of a focimeter is the key to fitting qualified glasses.
The autofocus focimeter is currently the most widely used type of focimeter. How to operate it correctly? I would like to share my experience in daily work and discuss it with colleagues.
1. Preparation before measurement
Turn on the power meter switch, preheat for a period of time, and then start testing the glasses. The inspector sits in front of the focimeter, places the glasses on the lens bracket of the focimeter, with their eyes facing directly towards the lens bracket of the focimeter. Lower the lens holder and secure the glasses properly; Rotate the handle of the lens table with your right hand to slowly rest the lens table against the glasses to be tested. At this point, the nose bracket of the lens frame matches the simulated nose bridge of the power meter; The inspector holds the glasses with their left hand while keeping them horizontal.
2. Top power value
Rotate the lens table movement handle with your right hand to move the lens table. The lens table pushes the glasses vertically to move at a constant speed during the movement process; Carefully move the glasses horizontally with your left hand; Move the optical center of the eyeglass lens to coincide with the crosshair of the power scoring board, press the memory button, lock the number displayed on the display screen, which is the top power value of the eyeglass lens. To prevent confusion between the left and right lenses when measuring and fitting glasses, always adhere to the principle of first right then left, that is, first check the right lens of the glasses, then the left lens. Use a spotter to dot the optical center of the eyeglass lens. Move the matching glasses to the left lens and perform the same process.
The horizontal distance between optical centers, the horizontal deviation between optical centers, and the axial direction of astigmatic lenses have been given simultaneously when measuring the top power value. The vertical deviation of the optical center cannot be given at once, and further measurement is needed.
3. Vertical mutual deviation of optical centers
The vertical deviation of optical centers is manifested as the inconsistent height of the optical centers of two lenses, one eye high and the other eye low. The optical centers of the left and right lenses are on two parallel lines L1 and L, so it is not possible to directly measure the vertical difference between the optical centers. However, we assume that the optical center vertical line L of the right lens is moved parallel to the optical center vertical line L1 of the left lens until it coincides, thus measuring the distance between two points on a straight line.
Find the optical center of the right mirror lens of the glasses, use a dotter to dot, mark A; Then move the glasses horizontally to the left lens, without rotating the lens table handle at this time. Just slightly adjust the left lens horizontally to the vertical line L1 of the optical center of the left lens, mark A1 with the puncher, and imagine that A1 is the optical center A of the right lens moving horizontally to reach the position behind the vertical line L1 of the left lens; Rotate the lens table movement handle, and the lens table pushes the glasses vertically to the optical center of the left lens. The puncher marks B, which is also the position of the optical center of the left lens in the vertical direction. The distance between A1B is the vertical difference between the optical centers of the glasses.