Surgeons utilizing the iVIS Suite can choose from a variety of treatment strategies to provide the patient with optimized safety and clinical results. Uniquely, the iRES™ laser can be used with LASIK, LASEK, PRK, femto-second laser LASIK, and a new advanced surface ablation strategy called cTEN™. cTEN, is a one-step, no-touch, all-laser process in which a custom refractive treatment is performed without the discomfort of keratome or laser keratome high level suction on the eye, and with the safety advantages of not creating a flap in the stroma.

Surgeons that have experienced the cTEN difference have rapidly migrated their patients to the cTEN procedure.

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1. Irregular Epithelial Thickness

The corneal epithelium's thickness is variable serving as a natural agent to mask corneal injury and irregularities. The epithelium is not well measured as a 3-D element using normal techniques. The malleable yet fluid tissue contributes significantly to regression and yet will also improve vision over time with some prior refractive surgery due to its natural tendency to eliminate discontinuity.

The importance of the epithelium to the final refractive outcome is commonly underestimated.

Local defects and regression changes, often the origin of significant irregular astigmatism, result in or from epithelial thickening. LASIK and standard surface treatments unfortunately create and then treat a surface that is unmeasured diagnostically. This unmeasured surface has different refractive (aberrations) and shape properties than those that were measured and used to plan the surgery. The assumption that a LASIK prepared surface or a standard de-epithelialized surface have the same properties as were measured diagnostically can be very misleading.

Only cTEN treats the measured corneal surface.

cTEN uniquely removes the necessary epithelium depth that has contributed to regression by removing a constant depth across the full treatment area. This depth approximates the epithelium thickness but is ideally a midpoint between the depth of the epithelium and the depth of the custom refractive component. Importantly the epithelial area is atraumatically removed, has minimized area being exactly "right-sized" to the custom refractive treatment area, and has smooth Gaussian shaped epithelial borders. These features encourage rapid, normal re-epithelialization.

Epithelium removal is accomplished in only seconds.

The custom refractive treatment is performed simultaneously with the epithelium removal. The iRES laser uniquely operates at 1 KHz but is variably tuned to deliver a Constant Frequency / Area™. Thusly a remarkably smooth and predictable total ablation is performed in only seconds, irrespective of the refractive treatment performed. This "no-touch" surgical strategy is patient friendly, eliminates complications associated with LASIK flaps, and avoids creation of a corneal interface persistent lifelong.

Additional interfaces are the enemy of quality of vision.

Planned with the surgical design application CIPTA, the custom surgical plan results in development of an Ideal Shape™ from a synthesis of shape, refractive, and pupillometry data. Clearly different from standard  wavefront surgery, this asphericity optimized shape does not add aberrations from the patient's lens or other ocular media to the surface of the cornea. The junction between the refractive area and border of the ablation is also optimized using iVIS' exclusive Constant Slope - Variable Width™ transition zone to further mitigate the risk of regression.

The Ideal Shape includes an optimized variable width transition zone.

With the custom ablation having been precisely positioned using the six elements of iFIDELITY™, the resultant aspheric stromal surface is highly regular. This highly regular surface yields a strong tendency for the epithelium to remain as a constant thickness, thusly tending to avoid regression.

The success of the cTEN treatment is not a function of just the iRES laser, but is due to the comprehensive details from diagnostics, planning, and delivery with the industry leading iVIS Suite.