How should the axial position of astigmatism be measured? _Industry information_
Like myopia and hyperopia, astigmatism is an abnormal refractive condition of the eye, and it has a lot to do with the curvature of the cornea. However, a patient with astigmatism, whether the vision seen in a certain direction is clear or blurred, is determined by the degree of the axis of astigmatism. Therefore, measuring the axial position of astigmatism is the main premise for understanding astigmatism. Let's take a look at how to measure the axial position of astigmatism. Astigmatism includes myopic astigmatism and hyperopic astigmatism, but no matter what type of astigmatism it is, the axial position of astigmatism can be determined by using a moving light band. At present, there are three methods for measuring the axial position of astigmatism in the optical shop (optical shop), namely the conventional method, the synergistic method and the forward and backward method. Conventional method: It is the most commonly used method to measure the axial position of astigmatism, and is suitable for astigmatism of +0.75 ~ +1.00D. For example, for a patient with renaturing hyperopia astigmatism, place the parallel light on the 90° meridian, parallel to the skin light band; then place the light band at 85° and 95° respectively, if it is found that the light band in the pupil becomes the same as that on the skin. The strips of light are not parallel, the width becomes larger, the boundaries become blurred, and the 90° axis is sure to be correct. Synergistic method: This examination method is suitable for patients with astigmatism above 1.00 DC. It is assumed that the horizontal light band of the patient has been neutralized, and when the vertical light band is moving along, the cannula is slowly moved down with the thumb, Gradually brighten and narrow the vertical band of light in the pupil until it becomes brighter and narrower. Then use the index finger to gently rotate the lamp holder tube, so that the light band is deviated to 85° and 95°. If the light band is not as narrow and bright as 90~ at 85° and 95°, it can be determined that the axis of astigmatism is 90°. of. Forward and backward method: This method is suitable for patients with astigmatism whose astigmatism is below 0.75 Dc. Compared with the above two methods, the process is similar. It is only during detection that the examiner can lean forward, and the examiner can lean forward, which can narrow the light band and make the axis of astigmatism more obvious. Then slowly rotate the lamp holder tube with the index finger, so that the light band is deviated to 85° and 95°, and the axis of astigmatism is determined. As one of the most common refractive errors in adolescents, astigmatism affects the physical development of adolescents, so accurate measurement of the axial position of astigmatism can accurately treat astigmatism.