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IEK for Professionals

Modesto / Stockton IEK Specialist – Dr. Ash
Information for Professionals

IntraLase Enabled Keratoplasty brings about the marriage of classic cornea and the refractive surgery. The ultra-high precision computer guided laser is used to perform tissue dissection that is not possible to perform by human hands. Much credit must be given to my mentor, Roger F. Steinert, MD, Professor and Chairman at University of California, Irvine, for advancing this science. All our patients stand to gain from this technology with better wound healing, strength and reduced corneal irregularity. Many of the phrases and terms used here may be from his lectures.

Pre-Operative Considerations

The patient chosen for IEK typically are ones that require full penetrating keratoplasty that have sufficiently clear peripheral corneas that the IntraLase would have enough optical penetration to perform the proper dissection. I have found the Visante Anterior Segment OCT from Zeiss to be utterly invaluable for preoperative work-up. The Visante Pachymap allows for very precise measurement of the peripheral corneal thickness. The software version 2.0 or newer of the Visante provides a Global Pachymap that produces 16 images for the map construction. See the images below.

Visante global pachymetric map of the cornea captures 16 images of the cornea to provide a thickness map

The images are then translated into a corneal thickness map like the one below.

Visante Global Pachymap data placed in a graphic display with tables.  This is a map created by the Visante 2.0 Software

The diameter of the IEK typically falls in the 8–9 mm range, therefore the pachymetry readings from the 7–10 range are used for best estimation. One would desire a 70 micron uncut tissue left at the bottom of most posterior aspect of the cornea.

Surgical Considerations

My preference is for performing the IntraLase cut on the same day as the day of the surgery. So the patient arrives a few hours prior to the operating room time, has the laser cut, and then goes to the operating room for the completion of the transplantation.

Cornea with central opacity  

Here is the image of a cornea before IEK. The patient has central corneal opacity of both eyes. One eye has already had a standard corneal transplant surgery with excellent results. She is now having corneal transplant surgery by the IntraLase Enabled Keratoplasty method.

 

On the morning of the IEK, the patient is marked with Gentian Violet pen in the central of the cornea at the slit lamp. I used an RK marker to further delineate the central cornea. I only placed ink on the central most portion of the marker to avoid interference with the femtosecond laser.

Corneal MarkingCorneal Marking before the IntraLase Enabled Keratoplasty

As noted above, one would desire a 70 micron uncut tissue left at the bottom of most posterior aspect of the cornea. The IntraLase femtosecond laser is programmed and the cornea is cut. In case of the patient below, her peripheral corneal thickness was 550 microns, so I programmed the posterior side cut to start at 480 microns. All the cut parameters are shared between the tissue bank and the surgeon to make certain of identical matching corneas. Patients seem to tolerate topical anesthesia with simple proparacaine quite well. Although the procedure takes about 90 seconds, my patients have experienced minimal, if any discomfort.

IntraLase Computer panel during IEK 

IEK wound

Here is a picture of the cornea immediately after the completion of the IntraLase procedure.

Cornea after IEK
Corneal tissue is shipped directly from SightLife, precut.

The donor tissue is either cut by the surgeon or the tissue bank. I have worked with SightLife Tissue Bank and have been extremely pleased. The tissue arrives precut. See the images below:

The image on the left shows the bottle. The cornea can be seen at the bottom of the bottle. The image on the right is a slit lamp photo of the same tissue.

Magnified image of the precut IntraLase Enabled Keratoplasty (IEK) donor corneal tissue
Highly magnified IntraLase Enabled Keratoplasty (IEK) donor corneal rim cut by SightLife in ZigZag B format

Look at the edge better on the left.

The edge on a high magnification clearly show the ZigZag standard B pattern as defined by SightLife tissue bank. Here is a Visante Image of the Button.

Visante image of an IEK Donor tissue cut in ZigZag format
Once Patient is taken to the OR, the standard ophthalmic blocks may be performed. Using the Sinsky hook or similar device, the cornea's lamellae are dissected and the host cornea is removed. Here is an image intra-operatively, one can clearly see the ZigZag wound specially at the 6-8 O'Clock View. Host tissue has been removed in this IEK Patient.  Note the ZigZag wound formation of the host

The ZigZag donor is placed in the identially cut ZigZag IEK cut host by Dr. Ash and secured using a running suture

Once the Donor Cornea is placed into the wound, it is amazing how the wounds self-align. The anterior chamber maintains very well and despite even loose sutures, the would remains Seidel negative.

The Surgical procedure is very much similar in concept to the standard PK, and all the same consideration apply.

 

Post-Operative Considerations

 

Here is a picture of the cornea one day after IntraLase Enabled Keratoplasty corneal transplantation. It is amazing how the corneal wound is perfectly aligned with absolutely no over-riding or under-riding of the transplanted tissue.  IntraLase Enabled Keratoplasty (IEK) performed by Dr. Ash post op on day 1
Many of the management issues are similar to the standard transplant. Risks of rejection should theoretically remain the same. Here are some images of 4 weeks post-op.  Visante image of a ZigZag B IEK with an Anterior Chamber Lens in place
 

Here is a magnified image of the transplant wound. The red dots are placed to more clearly demonstrate the ZigZag pattern B. If you look at the Visante image of the above free corneal button, you will see the exact same pattern.

 

 

 Highly Magnified ZigZag B IEK wound traced in red dots by Dr. Ash

IntraLase Enabled Keratoplasty is an enormously exciting new technique that will likely revolutionize the future of corneal surgery. I am thankful for the guidance and mentorship that Roger Steinert, MD has provided me.

 

 

 

 

 

Page Last edited 07/04/11


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