Boxing System

Posted by on May 5, 2010 in Dispensing | 4 comments

In 1962 the Optical Manufacturers Association adopted the boxing system to provide a standard for frame and lens measurement that greatly improved upon the accuracy of previous systems. The boxing system is based upon the idea of drawing an imaginary box around a lens shape with the box's sides tangent to the outer most edges of the shape. The system uses the sides of the boxes as reference points for the standard system of measurements. "A" Measurement - The horizontal distance between the furthest temporal and nasal edges of the lens shape or the distance between the...

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Transposing Prescriptions

Posted by on May 5, 2010 in Dispensing | 10 comments

Depending on the equipment used by the doctor, a prescription may be in plus or minus cylinder form. For surfacing, the lab uses the minus form, meaning if a prescription is written in a plus cylinder form it must be transposed before processing. Transpose a prescription written in plus cylinder form to minus cylinder form as follows: 1. Add the sphere and cylinder powers to determine the new sphere power. 2. Change the sign of the cylinder. 3. Change the axis by 90 degrees. Example: Transpose -3.00 +2.00 x 30 1. Add the sphere and cylinder powers to determine the new sphere...

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Dispensing with the Y-Stick

Posted by on May 4, 2010 in Dispensing | 0 comments

Y-Stick assists the optician, using the traditional manual method of marking the fitting crosses. The measurement is consistent; as long as the customer assumes the same body posture, the measurement will be the same. Any subjectivity on the part of the optician has been removed. How the Y-Stick works: Y-Stick always shows the horizontal along the front and rear pins of the swinging plumb-line. With the lightest touch the optician can freeze the plumb-line and record the horizontal line of sight for the patient in any posture. Because the optician operates the brake arm from the side, the...

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The Dangers of Night Driving Glasses

Posted by on May 4, 2010 in Dispensing | 168 comments

It is an all too common misconception that yellow tinted or yellow polarized night driving glasses are beneficial for night time driving. The thought is, the yellow or amber color reduces glare and improves contrast. However, in reality, when driving at night or dusk in already limited lighting conditions, ANY tint further reduces the amount of light transmitted to the eye, and consequently, further impairs vision. The problem is compounded as the yellow tint gives the wearer the impression they are seeing better, when in fact the reverse is actually true. "Yellow 'Night Driving' lenses have...

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Harry A. Saake’s 44 Tips for Dispensing Opticians

Posted by on May 4, 2010 in Dispensing | 3 comments

1. If you have a high plus lens, stay away from long narrow frames as they will tend to pop out of those frames the easiest since they are long across the top. One must understand that one of the reasons for having trouble keeping lenses in a metal frame is the eyewire. When tightened the eyewire has a natural tendency to straighten. You can prove this by taking a piece of string, putting it into an arc and then pulling on both ends. That's what your eyewire does and why there is more problem with plus lenses. 2. When determining if a frame is straight, the first thing you have to look at is...

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