With Retinoscopy

• 1)Refining Ret Cylinder: leave it in the trial frame

  • Leave estimated cylinder at the estimated axis found in ret in the trial frame
  • Hold handle of JCC parallel to the trial frame axis
  • Move JCC on the preferred side, towards -ve power (SAME COLOUR)
  • Do this until there is no preference
• 2) Refining power: estimated cylinder already in trial frame

  • Hold the cross cylinder so +ve axis markings parallel to trial cylinder axis (both colours)
  • Twirl the cross cylinder offering +ve and -ve positions

  *No difference = correct power

  *Preference = -ve add more cyl , +ve take away cyl

  • Continue to adjust the power of the trial cylinder until the patient sees no difference or ‘reversal’ occurs

  *Reversal = leave patient on least -ve cyl

  ! for every -0.50DC added you must add +0.25 DS and for every -0.50DC removed you must add -0.25 DS
• 3) Checking Tests:

  • Measure VA of new results using Snellen
  • +1.00 Blur - should blur to 6/18
  • Duochrome - leave it on equal (red = older , green = younger )