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Custom-cut epikeratophakia for the treatment of early keratoconus can bring about rapid visual rehabilitation and stable refractive results without induction of irregular astigmatism or risk for graft rejection, according to Jörg H. Krumeich MD.

"Custom-cut epikeratophakia has many advantages compared with penetrating keratoplasty for the treatment of eyes with stage I or II keratoconus. It preserves the patient’s cornea, thus avoiding problems with rejection, it corrects the refractive error, and it also seems to stabilise the disease, perhaps because the added tissue and circular scarring of Bowman’s strengthen the cornea. With its benefits, we believe custom-cut epikeratophakia deserves another look, and we invite others to participate in our ongoing study," said Dr. Krumeich at the annual ASCRS Symposium on Cataract, IOL and Refractive Surgery.

Recognising the problems associated with penetrating keratoplasty (PK), several years ago Dr. Krumeich decided to re-examine his past experience with custom-cut epikeratophakia. In reviewing his records, he identified 38 patients who had been operated on with that technique during the late 1980s and early 1990s. In all of those cases, the refraction was carved into the lenticule using the so-called refractive bench on which a microkeratome cut was performed on upside-down fixated lenticules over hyperopic or myopic dies.
All eyes had at least five years follow-up after their procedure, and during that time, refractive errors stayed identical and visual acuities remained good.

"Because of the unexpected outcomes of stable refraction and K-readings one must conclude that the disease had stopped with the placement of the epikeratophakias," Dr. Krumeich said.
Interested, therefore, in resuming custom-cut epikeratophakia again, Dr. Krumeich decided to use an excimer laser to create a more customized donor button bearing the negative of the individual’s subjective refraction.


Lenticule under excimer laser, mirror-wise tissue ablation from parenchymal side	Excimer carved epi button placed in recipients trephination

Initially, he used either the Nidek EC 5000 or Bausch & Lomb 217 lasers.
More recently he has used the Alcon LADARVision 4000. In addition, he has been using the Guided Trephine System (GTS) to determine the diameter of the epi button prior to the MK-cut. Both are performed on the artificial anterior chamber bench of the GTS.

Reviewing a series of eight eyes having three to five years of follow-up after undergoing custom-cut epikeratophakia with this more contemporary technique, he found they also achieved stable refractive and ophthal- mometric values after suture removal. Pre-operatively, the eyes had irregular astigmatism with an average cylinder of 4.6 D. After the custom-cut epikeratophakia, mean cylinder was reduced to 2.6 D and was regular, and BSCVA improved from 20/50 to 20/30.

"The outcome is not perfect as it appears. The trephination is associated with some steepening. However, the residual refractive errors are low and easily corrected with glasses," Dr. Krumeich said.

In his current procedure for custom-cut epikeratophakia, Dr. Krumeich dissects an 8 mm, 300 micron thick button from the donor cornea using the GTS. Any trephine can be used, but the GTS produces a 360-degree cut, and it makes even, circular undercuts with high precision for the depth at the intended plane, he noted.

Next the button is placed on a shelf where the refraction is put in mirror-wise with the laser. On the recipient cornea, the GTS is used to dissect an area 350 microns deep and 7 mm in diameter. The button is placed into the bed and fixated with double-running anti-torque 10 x 0 nylon sutures.

"In contrast to the Kaufman method where there is corneal compression, with this technique a surface button is placed that conforms well to the patient’s cornea. Although suture fixation is needed to assure consistent adaptation for the healing of the epi button, the sutures do not create any tension and are taken out after one year," Dr. Krumeich said.

He added that use of fresh versus frozen tissue is preferred for the donor button since shrinkage that occurs with freezing introduces some unpredictable refractive error, and the frozen tissue procedure is also associated with a prolonged healing period.

"It can take months for visual rehabilitation after epikeratophakia with frozen donor material, but with fresh tissue, vision returns to 20/30 at most within a few weeks," Dr. Krumeich said.
He noted he was particularly motivated to look for alternatives to PK for treatment of early keratoconus based on his own and other data showing the high reoperation rate associated with PK.

"There are many reasons to look for an alternative to PK, but in addition to the obvious problems, our own recent evaluation of about 2000 cases revealed the reoperation rate was much higher than we expected. With the introduction of Optisol for preserving donor eyes, there is a continuous decay of endothelial cell counts, and as a result, reoperation rates reach 10% at six years and 35% after 10 years. Those findings have been confirmed by the Australian Cornea Graft Registry. This means that we cannot tell a young patient that PK will offer a permanent cure. Rather, some of these individuals might need to undergo the graft procedure five times over the course of their lifespan," said Dr. Krumeich.

Jorg H. Krumeich MD
Marien Hospital 44866 Bochum, GERMANY
jd@krumeich.ruhr.de

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