Joja Surgicals Pvt. Ltd.www.jojasurgical.com

jojasurgical@gmail.com

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 misalignmentIn a 6 D Toric – error is 1 DIn 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 markersWith 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. Set the slit lamp beam to the desired placement axis

2. Align the beam to pass through the corneal centre (described later)

3. 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 measuringCentration of IOL, rhexis, pupilMeasurement of rhexis / pupil areas

and diametersAngular measurements of Toric IOLs

Planiware can be downloaded from www.suryodaya.in/planiware

Verifying your markings