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Getting the Markings Right

Joja Surgicals Pvt. Ltd. www.jojasurgical.com jojasurgical@gmail.com. Getting the Markings Right. Why is Marking Important?. For every degree of rotation 3.3% of the effect is lost With 30 degree rotation all effect of the Toric lens is lost Beyond that you start adding to the astigmatism.

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Getting the Markings Right

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  1. JojaSurgicals Pvt. Ltd. www.jojasurgical.com jojasurgical@gmail.com Getting the Markings Right

  2. Why is Marking Important? • For every degree of rotation 3.3% of the effect is lost • With 30 degree rotation all effect of the Toric lens is lost • Beyond that you start adding to the astigmatism

  3. Why is Marking Important? • Higher the Toric correction greater the chances of errors • e.g. For a 5 degree misalignment • In a 6 D Toric – error is 1 D • In a 1.5 D Toric – error is 0.25 D

  4. So let’s get the marking spot on ! • Two issues in marking • Making sure our 0 – 180 meridian is ‘true’ horizontal • Making sure that the marks bisect the cornea through the optical centre

  5. Current Markers • Hand held markers • With spirit level to ensure horizontality

  6. Current Markers • Do not ensure that the marks pass through the centre of the cornea

  7. Are you bisecting the cornea?

  8. Current Markers • You also need a second intra-op mark if the placement axis is not 0 – 180

  9. Current Markers • Come in only one size • But the corneas are not of the same size or shape!

  10. Issues • Still does not solve the problem of bisecting the cornea through the optical centre

  11. A New Approach • A slit lamp based system • Uses gravity to define horizontal • Uses Purkinje images to ensure centring on the cornea

  12. 3 Simple Steps • Set the slit lamp beam to the desired placement axis • Align the beam to pass through the corneal centre (described later) • Mark the cornea

  13. Step 1 – Setting the Angle • The slit beam can be set to the axis of placement • No need for reference marking Clamp device to chin rest of slit lamp

  14. Setting the Angle

  15. Step 2 • Unclamp the calibrator device • Place the patient’s head normally on the slit lamp

  16. Centring on the Cornea • Patient looks at the light with the other eye closed • Move the slit beam across the cornea until you get a bright Purkinje image

  17. Centring on the Cornea • Images bordered in red show the correct positioning of the slit beam

  18. How do we know it is accurate?

  19. Planiware 2.0 • This is a IOL planimetry software designed for measuring • Centration of IOL, rhexis, pupil • Measurement of rhexis / pupil areas and diameters • Angular measurements of Toric IOLs • Planiware can be downloaded from www.suryodaya.in/planiware

  20. Verifying your markings

  21. Happy marking!

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