How to check out astigmatism

Astigmatism can generally be detected by optometry, astigmatism table examination and keratometer examination.

1.

Optometry is to project light to the patient's eye through the optometry lens. By observing the movement of the shadow reflected by the retina to the pupil area, it is judged whether the shadow is in parallel, combined or scattered state. If the neutral point on the two principal meridians in the optometry is different, it indicates that the patient has astigmatism.

2. Astigmatism table

examination is a method to check the astigmatism axis with astigmatism table. The patient determines the astigmatism axis by observing the clarity of each line of the astigmatism table.

3. Keratometer

examination is to put an object of a specific size at a specific position in front of the cornea. After the object is reflected by the cornea, the radius of curvature of the anterior surface of the cornea can be calculated by measuring the size of this image, so as to determine whether there is astigmatism and astigmatism axis.