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How To Measure Prism In A Lensometer
How To Measure Prism In A Lensometer
November 07, 2024
- Place the glasses on the patient With a felt-tipped pen, mark the center of the patient's pupil Vertical positioning is negligible but should be closed.
- Center the mark for the right lens on the lensometer Remove any vertical displacement
- Any remaining deflection in the x-axis is the amount of horizontal prism for this lensnotice the rings that are numbered, each ring represents a degree of the prism, the direction of the prism in the direction of mires are when focused ( can be up or down for vertical ) Record the eye, amount, and direction (i.e., 2.5∆ BO OD)
- Repeat for the left lens.
- Total horizontal prism is the sum of each eye's prism
- Bases in the same direction are additive (BO/BO or BI/BI)
- Bases in the opposite direction are subtractive (BO/BI or BI/BO)
