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Joja Surgicals Pvt. Ltd.
www.jojasurgical.com
[email protected]
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

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
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
Current Markers

Hand held markers
 With spirit level to ensure horizontality
Current Markers

Do not ensure that the marks pass
through the centre of the cornea
Are you bisecting the cornea?
Current Markers

You also need a second intra-op mark if
the placement axis is not 0 – 180
Current Markers
Come in only one size
 But the corneas are not of the same
size or shape!

Issues

Still does not solve the problem of
bisecting the cornea through the
optical centre
A New Approach
A slit lamp based system
 Uses gravity to define horizontal
 Uses Purkinje images to ensure
centring on the cornea

3 Simple Steps
1.
2.
3.
Set the slit lamp beam to the
desired placement axis
Align the beam to pass through the
corneal centre (described later)
Mark the cornea
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
Setting the Angle
Step 2
Unclamp the calibrator device
 Place the patient’s head normally on
the slit lamp

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

Centring on the Cornea

Images bordered in red show the
correct positioning of the slit beam
How do we know it is accurate?
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
Verifying your markings