Lens Fitting

The V Kone Lens has a large optical zone and tapered peripheral curves to align with the healthy periphery of a keratoconus patient. The V Kone lens provides the centration, comfort and tear flow provided by the parabolic curves along with cylinder control based on improved E-value properties and a larger optical zone. With E-value encapsulated inside the base curve, a natural progression of flattening occurs. This creates the opportunity for optical zones to be up to 2mm larger than any prior keratoconus lens design. Control over lenticular astigmatism is significantly improved. The crispest visual acuity and aberration control outside of a toric lens is generated within this moldable model front surface E-value system. The pellucid marginal degeneration patient has long been a fitting challenge for practitioners. V Kone simplifies the challenge by customizing all meridians to vault over any ectasia and avoiding mechanical rubbing that is attributed to scarring, even on low-ectatic corneas.

1. Begin with a base curve one diopter flatter than the steepest K reading in order to slightly vault over the central cornea.
2. Analyze the horizontal meridian for an even band of fluorescein.
3. Determine whether the standard edge lift is acceptable or an adjusted peripheral curve is needed. (The peripheral curves can be ordered in a "step" system to achieve the best possible fit.)
4. Some slight inferior edge lift is expected.
5. Simply over-refract, attempting for the best vision with a spherical over-refraction.