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Standard alignment
1. Standard plastic frames must be heated to adjust alignment, using either hot air, salt, or glass beads. The bridge and temples can be bent to correct horizontal, vertical, and coplanar alignment. 2. Temple spread, which is the angle of the temples from the front of the frame, should usually be 94-95 degrees. Temple spread can be adjusted by heating and bending the temples or endpieces. 3. Temples must be parallel to check for proper alignment. The flat surface test checks if both temples sit evenly. Causes of improper parallelism include bent endpieces, hinges, or temples.
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Standard alignment
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- 2. Standard alignment ofplastic frame HEATING THE FRAME Standard plastic frames must be heated for any alignment. Standard procedure for adjusting the frame should be followed, beginning with the bridge. Frame may be heated using Hot Salt or Glass Beads Forced Hot Air
- 3. WITH HOT AIR: 1.Heat only the portion of the frame to be worked on. 2. Rotate the frame in the heat. (This is especially important for warmers having heat coming from one direction only.) 3. Check the type of frame material. Some materials can stand more heat than others.
- 4. WITH SALT ORBEADS: 1. Ask yourself, “Should this frame material or these lenses be subjected to salt or beads?” If there is any doubt, use hot air. 2. Always stir the salt (or glass beads) first. 3. Keep the area of the frame being heated parallel to the surface of the salt. 4. Keep the frame moving slowly. 5. Heat only the portion of the frame to be worked on
- 5. An example ofa frame that has been overheated, resulting in bubbling of the plastic on the upper rim.
- 6. THE BRIDGE Anumber of thing may be error in relation to bridge The bridge itself mainly judged by the effect it has on the plane of lenses Readjusting the lenses to their proper plane is done by heating the bridge area, then grasping the frame by lens area and adjusting according to the correction needed
- 7. Adjustment using saltpan Place the frame in the pan temples up and through the peak of salt mount Repeat this until the bridge is flexible enough to be bent
- 8. Adjustment using forcedhot air When using hot air concentrate the air stream on bridge Move the bridge through the hot air stream until it become flexible Then it can adjusted to desired correction
- 9. If thelens is deviated from horizontal plane they are said to be out of horizontal alignment If the lens is deviated from vertical plane they are said to be out of vertical alignment
- 10. Horizontal alignment Tocheck for horizontal alignment, place a ruler or straight edge across the back of the frame at the top of the pads If there are no pads, there may be a point where the sculptured shaping of the bridge area ends . Both end pieces should be equidistant from the straight edge when it is aligned horizontally. A practiced eye may be more helpful than a rule
- 11. There are twocommon causes for a frame being out of horizontal alignment: • a rotated lens • a skewed bridge.
- 12. Rotated lens Alens rotated in the frame will cause the top of the eyewire to either hump up at the nasal bridge or one endpiece to appear upswept in shape To correct the problem, use lens rotating pliers.
- 14. Skewed bridge Whenviewed from the front, a skewed bridge will cause one lens to appear higher than the other This problem usually only happens after the glasses have been dispensed and something has happened to them To correct a skewed bridge, first heat the bridge, then grasp the front with an eye wire in each hand Force the eye wires in opposite directions until the tops of the eye wires are parallel.
- 15. To correct fora skewed bridge, heat the bridge and force one side up and the other down. An example of a skewed bridge. It will be noted that neither of the lenses shows any twisting. The error is manifested by one lens being higher than the other.
- 16. Vertical Alignment (Four-Point Touch) To check for vertical alignment, or four-point touch, place a ruler or straight edge so that its edge goes across the inside of the entire front of the spectacles below the nosepad area. Theoretically the frame eyewire should touch at four points on the ruler . However,this ought to only be the case if the frame is small compared with the wearer’s head size, otherwise face form is required.
- 17. Vertical misalignment Faceform Xing Variant Planes
- 18. Checking for four-pointtouch. The frame eyewire touches at each place where the ruler crosses the eyewire. This indicates correct alignment when the “frame PD” equals the wearer’s interpupillary distance.
- 19. Face form orwraparound Face form is when the frame front is just slightly rounded to the form of the face. Most frames are constructed with at least a degree of face form. This is especially true of large frames and thick metal frames. Frames with face form will not conform to the fourpoint touch test, but must be symmetrical nonetheless. The temporal sides of the eyewires should touch, and the nasal sides should be equidistant from the ruler
- 20. Too muchface form would be evident if the two nasal eyewires are a great distance from the ruler. Too little face form is the case if neither temporal eyewire, but only the nasal eyewires, touch The remedy for either too much or too little face form is to alter the bridge. First warm the bridge until it is pliable, then grasp the frame by the lenses and eyewires with thumbs on the inside and fingers on the outside. Bend the bridge by turning the lenses inward or outward
- 22. Xing The framefront may be twisted so that the planes of the two lenses are out of coincidence with each other. This is called Xing because the eyewires of the frame front form an X when viewed from the side X-ing causes the temples to be out of line with each other. Whenever the temples do not appear parallel, the frame X-ing is corrected by grasping the eyewires and rotating the hands in opposing directions until the planes of the lenses are parallel.
- 24. In grasping theframe to correct an X-ing error, the wrists move in opposite directions.
- 25. when thelens planes are variant, or out of coplanar alignment. In this situation, the lens planes are parallel, but one lens is farther forward than the other This error usually becomes apparent when the four- point touch test is used, although it may easily be overlooked otherwise To correct a frame with lenses out of coplanar alignment, first heat the bridge and grasp the frame in the manner.
- 26. Here is anexample of lens planes that are variant or out of coplanar alignment. In spite of the improperly bent bridge, the lenses remain parallel to one another.
- 27. Temple After horizontaland vertical pre adjustment have been done to bridge and eye wire. next accept to consider how far the temple spared To allow a good picture of temple spared temple shaft must be straight Any curve to temple shaft must be eliminated by heating the temple and straightening with hand
- 28. Open temple spred The open temple spread, or let-back, is that angle that each open temple forms in relationship to the front of the frame It is the normal condition of the temple to be opened out slightly farther than a 90-degree angle; usually 94-95 degrees
- 29. Temple Spread Temple notspread enough Temple spread too far Temple spread unequal
- 30. Temple spread toofar Temples fl aring out more than 95 degrees are spread too far for standard alignment Glasses tends to slide down the nose
- 31. How to correctit ?.... Too far [bend the temple inwards Using the thumb Using a fl at surface Bend eye wire and endpiece Bend the butt portion of the temple Sink the hidden hinge deeper into the frame front
- 32. Using the thumb— Onemethod of decreasing temple spread involves holding the frame by the lens and eye wire while pushing the end piece back with the thumb.
- 33. Using a flat surface— One of the easiest and most successful methods of reducing temple spread is pressing the endpiece against a fl at surface.
- 34. Bend the buttportion of the temple— Brace both eye wires with the fore finger and press the endpiece with the thumb to decrease the temple spread.
- 35. Sink the hiddenhinge deeper into the frame front— If no other method proves successful, it is possible to bring the temples in by grasping the temple butt with half-padded pliers and bending the temple with a free hand.
- 36. Temple not spread enough Occasionally the temples are not spread enough after the lenses have been inserted and the bridge area straightened. The lens may not be completely in the frame at the endpiece. The endpiece needs to be bentoutward. File the butt end of the temple. Bend the temple outward.
- 37. How to correctit ?.... Not spread enough [bend the temple outwards The lens may not be completely in the frame at the endpiece. The endpiece needs to be bentoutward. File the butt end of the temple. Bend the temple outward.
- 38. To spread thetemples, heat the endpiece and pull back with the fi ngers while pressing with the thumbs.
- 39. Temple parallelism Instandard alignment the two temple must be parallel to one another when viewed from the side. The flat surface touch test is used to check temple parallelism: Position the glass upside down on a flat surface with temple open Note whether both temple sit flat or one temple is not touching the flat surface Touch the first one temple and the other to see whether the frame wobble back and forth
- 40. Causes of incorrecttemple parallelism A bend end piece A broken rivert and lose hidden hinge A bent temple shaft A bent hinge A twisted bridge