Frequently Asked Questions


What is the ComfortKone Lens?
ComfortKone is an FDA Cleared RGP contact lens design for Keratoconus applications. The ComfortKone Aspheric is the most advanced lens for patients in any stage of Keratoconus. This unique lens design provides consistent results with maximum comfort and visual acuity for keratoconus patients.

What does FDA Clearance mean?
The ComfortKone lens design holds an FDA 510k clearance specifically for Keratoconus application. This means that Metro Optics submitted lens design and patient case information to the FDA demonstrating safety and efficacy of the lens on keratoconic corneas.

What is special about the ComfortKone?
This design uses a corneal alignment fitting approach to maximize comfort and visual acuity. The design features a comprehensive fitting system with controlled parameters that provide quick and consistent results, and the computer driven manufacturing systems used to create the ComfortKone ensures that every lens and fit is completely reproducible.

What are the design specifics?
The back surface of the ComfortKone lens is begins with a central spherical base curve zone which vaults over the corneal apex. It
transitions to an aspheric zone creating an alignment to the keratoconic slope. This base curve configuration causes the lens to center itself over the cone which is usually a bit off corneal center, and does not adversely affect vision or comfort. The back surface peripheral curves are similar to standard lens designs to provide maximum edge comfort and tear exchange under the lens. The front surface of ComfortKone can feature both spherical and toric optics.

Base Curve Evaluation
Slit-lamp evaluation of the lens will quickly reveal any necessary changes. After allowing the lens to settle for several minutes, instill fluorescein and use blue cobalt light with a wratten filter. The wratten filter will overcome the UV inhibitors present in the lens material so you can clearly see the tear film behind the lens. Note any areas of touch or excessive clearance from the lens center to edge. Send
photos and videos of the fluorescein patterns to your Metro Optics consultant. Be sure to use a wratten filter over the camera lens when capturing images.

The most accurate method for determining lens power for any keratoconus patient is to over refract over the best fitting diagnostic lens. This should be done following lens settling and base curve evaluation. A spherocylindrical over-refraction should be taken as the ComfortKone lens is available in toric optics.

What about empirical fitting of ComfortKone?
Although this not the ideal approach, a ComfortKone lens can be designed empirically with the aid of keratometry readings or corneal topography and manifest refractions with the help of a Metro Optics fitting consultant.

Learn More here about the ComfortKone design and our other Keratonus lens options.

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