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Text File  |  1997-10-29  |  1KB  |  24 lines
  1.                  KERATOMETER MEASURING TECHNIQUE
  2.  
  3. Making the Power Measurement
  4.  
  5. Once the horizontal lines of the plus signs are 
  6. aligned, rotate the horizontal power drum (on 
  7. left side) until the vertical lines of the plus 
  8. signs are overlapping.  Next rotate the 
  9. vertical power drum (right side) until the 
  10. minus signs overlap.  Be sure to overlap the 
  11. mires as accurately as possible.  It is often 
  12. necessary to refocus the mires during the 
  13. measurement and between reading the horizontal 
  14.                                            and vertical meridians.
  15.  
  16.                                                                         If the drum(s) are 
  17.                                            rotated to their full 
  18.                                            extent and the mires 
  19.                                            still do not align (the  
  20.                                            cornea is steeper or  
  21.                                            flatter than the range  
  22.                                            of the instrument), the                       
  23.                                            range of the instrument must be extended.
  24.