Corneal Pocket Concept
The lamellar nature of the cornea is characterized by some 200 successively stacked collagen lamellae. This particular structure allows optimal distribution of intra-corneal forces. A corneal pocket is defined as a almost entirely closed lamellar cut which preserve the biomechanics of the tissue. A corneal pocket can be used as an optimal starting point for complex corneal treatment strategies.
Material and methods. Corneal pockets can be created by 2 different types of technologies: first, the Femtosecond laser technology where the lamellar cut is created by means of a more or less brutal disruption of corneal tissue via small laser beams directed from in front of the cornea. Second, the PocketMaker technology where a micro-vibrating and ultra-thin diamond blade is guided on a micron accuracy level inside the cornea. The corneal pocket can be used for different procedures such as MyoRing implantation, instillation of riboflavin to bypass the epithelium, anterior or endothelial keratoplasty procedures, etc.
Results. Corneal pockets created by means of Femtosecond laser technology are characterized by a relatively uneven interface compared to the very smooth interface of pockets created by means of the PocketMaker Ultrakeratome. This differences in the method and quality of lamellar cutting have a significant impact on the results of these procedures. For instance in MyoRing treatment of Keratoconus and Myopia the final results are significantly better in the PocketMaker group compared to the Femtosecond laser group. Also in lamellar keratoplasty procedures the outcomes are better in the PocketMaker group. The accuracy of lamellar cutting is depth dependent in the case of Femtosecondlaser where the precision of cutting is significantly reduced the deeper the cutting is. The precision of lamellar cutting is independent from the cutting depth in the case of PocketMaker Ultrakeratome.
Conclusion. The very smooth cutting interface after corneal pocket creation by means of the PocketMaker Ultrakeratome results in a much quicker, much better and more predictable adaptation to the intended postoperative corneal shape after MyoRing implantation for Keratoconus or Myopia compared to treatment done with Femtosecond laser technology. This behavior can be explained by the higher friction in the interface between the anterior and posterior corneal lamellae when the cornea moves into a new equilibrium and shape.
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