Heralded as "a quantum leap forward in the evolution of lens design for the condition" of keratoconus, the Rose K lens has become the world's most frequently prescribed gas permeable contact lens for keratoconus.

Unlike traditional contact lenses, the complex geometry built into every Rose K contact lens closely mimics the cone-like shape of the cornea for every stage of the condition.

The result is a more comfortable fitting lens for patients and better sight (visual acuity).

The Rose K lenses' complex geometry has only become possible since computer-controlled contact lens lathes were developed to cut sophisticated oxygen permeable polymers to the right shape.

The Rose K lens has a number of features that make it ideal for keratoconus:
• Its complex geometry can be customized to suit each eye and can correct all of the myopia and astigmatism associated with keratoconus.
• They are easy to insert, remove and clean.
• They provide excellent health to the eye, because they allow the cornea to "breathe" oxygen directly through the lens.
• Practitioners have the Rose K trial set fitting system which achieves a first fit success in over 80% of patients internationally.
  Standard lens designs with fixed optical zones (OZ) do not ideally fit the cone shape of keratoconus patients. Figure 1 shows a standard lens that will yield unwanted pooling at the base of the cone and peripheral bearing that can seal off and cause corneal problems.
  This illustration demonstrates the benefits of a smaller optical zone to fit the cone contour. The design results in little tear pooling at the base of the cone and shows an even distribution of tears under the lens.

The Rose K system has set optical zones to maximize vision while maintaining good corneal health. 
Rose K2 Lens

The Rose K lens was further refined to take into account the unusual corneal shapes of keratoconus patients, which require abnormal curves on the back of the lens to fit the cornea optimally. This new lens is known as the Rose K2 lens.

With normal corneas the shape does not change dramatically from the center out, but tends to change evenly in predictable amounts, and therefore with normal corneas the back surface of the lens can be designed with small incremental changes (e.g. eccentricity) over most of the lens with a peripheral curve at the edge. Usually, this will achieve reasonable alignment with the cornea and a good fit.

However, to achieve optimum alignment with the cornea in keratoconus patients, many curves are required on the back surface of the lens, and adjacent curves are often very different. Particularly in steeper cones, several curves are often required within the patient's pupil zone to achieve a good fit over the central area of the lens. Unfortunately, each one of these curves gives rise to a slightly different focal point at the back of the eye. This causes the patient to experience ghosting around the object that they are viewing (like a TV with poor reception) and this is worse the bigger the pupil is because more curves on the back surface of the lens come within the patient's pupil zone. Therefore night driving where the pupil is larger is very difficult for keratoconus patients. These multiple focuses are called aberrations.

The Rose K2 lens minimizes these aberrations by applying very small changes to the curves on both the front and back of the lens in an attempt to bring the light passing through the lens within the pupil zone to a single point.

Following extensive trials, the best combination of aberration control curves have been developed for computerized digital lathes to cut these very complex curves for the Rose K2 lens to give the best focus.

Rose K Post Graft Lens
The Rose K Post Graft Lens is for patients who have undergone penetrating keratoplasty. This lens is designed for postoperative recovery and improvement in vision.

ACT (Asymmetric Corneal Technology)
ACT is quadrant specific and allows the steepening of the inferior quadrant onlyBy nature, the keratoconic cornea is asymmetric, where the inferior quandrant is frequently significantly steeper than the superior portion, causing the GP lens to lift off at 6 o'clock (see illustration E).

Rose K lenses incorporating ACT are designed to accommodate this asymmetry. The inferior quandrant of the lens is steeper than the superior quadrants, providing a more accurate fit at 6 o'clock, which makes the lens more comfortable and stable and often provides superior vision.