After you get your beloved glasses, the professional optometrist will carefully adjust the frame, first of all, adjust the position of the four contact points of the frame (two points on the bridge of the nose and two ears), so that the nose, ears, and forehead do not feel pressure and pain, so that you can wear the glasses for a long time and wear comfortably, so that you almost forget its existence.
Line: straight to straight, the sense of balance is particularly good in the optometry, grinding, has carefully measured your pupil distance, and align the lens, the professional optometrist still has to adjust according to your face shape, the horizontal line and height of the glasses, to determine the optical center of the glasses and the pupil position has been aligned.
The mirror tilt and the curvature of the eye surface must be adjusted parallel, the corneal vertex distance must be adjusted accurately, so that the light refraction through the lens, subsidizing the adjustment error of the eyeball, the image can be correctly imitated on the retina, otherwise the image will be distorted and not clear, and even cause dizziness.
Retinoscopy is usually used in clinical tests. When the eye is at rest (unadjusted), the light emitted by the macular fovea forms a focal point outside the eye after being refraction by the refractive system of the eye. This point and the macular fovea of the retina are conjugate focal points, which is called the distant point of the eye. The imaging method is based on the principle that the light emitted from the retinal illumination area is used to image at the far point, and the position of the far point of the eye is determined dynamically by observing the light and shadow in the pupil area. Specifically, at a certain distance (the inspection distance is usually 1 meter), the light is put into the examined eye with the imaging mirror. According to the dynamics of the light and shadow in the pupil area when the retinal reflex of the eye is emitted out of the eye, whether the emitted light is parallel, spread out or set, if the former means that the distant point is behind the eye of the examiner, if the latter means that the distant point is between the eye of the examiner and the eye of the examined. A convex or concave spherical lens and a cylindrical lens are then placed in front of the patient to offset the degree of the refractive error, so that the distant point of the examined eye is moved to the examination eye, and the diopter required to move the distant point to infinity is calculated. The algebraic sum of the resulting lenses is the patient's actual refractive error.