IEK 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, now 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.
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 newer software version 2.0 of the Visante provides a Global Pachymap that produces 16 images for the map construction. See the images below.
The images are then translated into a corneal thickness map like the one below.
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.
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.
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.
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.
Here is a picture of the cornea immediately after the completion of the IntraLase procedure.
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.
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.
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.
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.
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.
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.
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.
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. Any and all comments are welcomed. Please direct your email to me at DrAsh@ModestoEyeCenter.com
The physicians of Northern California Laser Center are renowned Modesto and Stockton lasik eye surgeons. They are also considered Modesto and Stockton cataract surgery specialists. These physicians treat LASIK Modesto and cataracts patients from their Modesto offices.