Spectacle frames for power-variation spectacles
1.Spectacle frames for power-variation spectacles
The distance between the two vertical sides of a rectangular frame that is tangent to the shape of the lens.
See Figure 1.
2.Vertical box lens size is the distance between the two horizontal sides of a rectangular frame in which the lens is shaped. See Figure 1.
Figure 1. Schematic Diagram of Front Frame Measurement
Symbol description:
C—— Center of the box method; a—— Horizontal size of the lens; b—— Vertical size of lens; c—— Center distance of box method; d—— distance between commutator segments
3.Lens Facial Curvature Face Form Angle The Angle Between the Plane of the Front Frame of the Mirror and the Plane of the Right or Left Lens. See Figure 2.
Note 1: If the temporal side of the right lens or left lens plane is closer to the head than the front frame plane of the spectacle frame, the facial curvature of the right lens ring or left lens ring is positive.
Note 2: The measurement value of the face curvature of the lens is usually specified as the average of а L and а R . If the face curvature of the lens changes significantly when the frame is adjusted for a specific wearer, the angles are specified as а R and а L respectively.
Reference number description:
1—— The intersection point between the front frame plane of the lens and the plane of the right or left lens;
2—— The plane of the left lens;
3—— The front frame plane of the lens;
4—— Right lens plane;
а R , а L —— right/left lens ring facial curvature.
Figure 2 Schematic Diagram of Lens Face Curvature (top View)
4.External Corner of the Zhang Outward Angle
The angle between the mirror leg and the line connecting the two hinge axes when the mirror leg is opened to the maximum position.
5.Side Angle, frame panoptic Angle
When the temple is opened, the angle between the normal line of the lens plane and the line connecting the midpoint of the hinge to the contact point between the lower edge of the temple and the human ear. See Figure 3.
Reference number description:
1—— Vertical reference line;
2—— Planar normal (vertical to the vertical reference line);
3—— Through the line parallel to the normal of the lens plane at the midpoint of the hinge, that is, the normal of the lens plane;
4—— The line connecting the midpoint of the hinge to the lower edge of the temple and the contact area of the human ear;
5—— Inclination (positive in this case)
Figure 3. Structural Diagram of Inclination Angle
Ask
1.Basic Requirements
The sweat resistance and corrosion resistance of the frame, the mechanical stability of the frame and the amount of nickel precipitation should meet the relevant requirements of GB 45184. The appearance quality, dimensional deviation, high temperature dimensional stability, coating bonding force, fatigue resistance, flame retardant and light radiation resistance of the frame should meet the relevant requirements of GB/T 14214. The nose pad and head of the frame of progressive focus glasses should be adjustable. The two sides of the temple should be spread flat or inverted to maintain four points in a plane.
2.Front Panel
2.1 Vertical Dimension of Square Frame Lenses The vertical size of the square frame lens should be 28 mm ~40 mm.
2.2 Horizontal Dimension of Square Frame Lens The horizontal size of square frame lenses should be 46 mm ~56 mm. 2.3 Distance Between Commutator Segments The distance between the plates should be 16 mm ~22 mm.
2.4 Nasal Pads The left and right lobes of the nasal pad should be symmetrical.
3.Lens Facial Curvature
The left and right lens circle facial curvature should be symmetrical, and neither is greater than 5°.
4.Outside the Horn
The outward opening Angle of the left and right mirror legs should be symmetrical, preferably 80° ~ 95°.
5.Angle of Roll
The inclination Angle of the left and right mirror legs should be 7°±2°, and the difference between them should not be greater than 2°.
Experimental Method
1.Basic Requirements
The test was carried out according to the methods specified in GB 45184 and GB/T 14214.
2.Front panel
2.1 Vertical Dimension of Square Frame Lenses
Measure with a measuring instrument whose minimum scale value is not greater than 1 mm as indicated in Figure 1.
2.2 Horizontal Dimension of Square Frame Lens
Measure with a measuring instrument whose minimum scale value is not greater than 1 mm as indicated in Figure 1.
2.3 Distance Between Commutator Segments
Measure with a measuring instrument whose minimum scale value is not greater than 1 mm as indicated in Figure 1.
2.4 Nasal Pads
The test shall be carried out according to the inspection and identification method specified in GB/T 14214.
3.Lens facial curvature
According to the indication in Figure 2, the measurement is made with a measuring instrument whose minimum division value is not greater than 1°.
4.Outside the horn
Measure with a measuring instrument whose minimum scale value is not greater than 1 °.
5.angle of roll
According to the indication in Figure 3, the measurement is made with a measuring instrument whose minimum division value is not greater than 1°.
Appendix A (Informational) Selection Guide
A.1 Structure and Material
Spectacle frames designed for progressive lenses should prioritize structural stability and lightweight construction. A robust design ensures precise alignment of the progressive lens assembly. Avoid using materials prone to deformation, damage, or poor adjustability in frame production. Such material choices prevent positional misalignment caused by frame warping, which may lead to discomfort when wearing progressive glasses.
A.2 Circular
For the spectacle frame used for the progressive lens, the circle should cover the distance area, progressive area and near area of the progressive lens, but avoid covering too much of the aberration area.The shape should be circular or square, not pear-shaped, as shown in Figure A.1.
3.Nasal Pads
The curved form of the leaf stalk should be S-shaped, as shown in Figure A.2.
A.4 Vertical Dimension of Square Frame Lenses
The vertical size of the square frame lens is usually selected according to the channel of the gradient focal lens. The longer the channel, the larger the vertical size of the square frame lens. However, the vertical size of the square frame lens should not be too large, otherwise it is easy to cause a large aberration area, resulting in wearing discomfort and increasing the difficulty of nose pad adjustment.
A.5 Horizontal Dimension of Square Frame Lens
The horizontal dimensions of square-rimmed lenses significantly impact the comfort and visual clarity of progressive glasses. Excessively large horizontal dimensions may create excessive aberration zones, potentially causing visual flickering and dizziness. To ensure optimal field of view and wearing comfort, these dimensions should be tailored to the wearer's facial profile.
Choose a progressive lens frame that does not require excessive movement of the center point position of the progressive lens. The deviation between the central distance of the square method and the distance to the fitting point should not be greater than ±6 mm. The eccentricity on one side should not be greater than ±3 mm, otherwise it may cause narrowed vision (see Figure A. 3).
