Conforma K

Keratoconus is a non-inflamatory protrusion of the cornea, usually affecting both eyes. It is characterized by thinning and steepening of the central cornea in a variable progression. The apex of the cornea is usually displaced downward and a mild or marked loss in vision results from the irregular corneal changes. Keratoconus detected early is best corrected with GP lenses. Even though good spectacle acuity may still be present, GP lenses will help the patient adapt to the inevitable. GP lenses will neutralize the distortions of the corneal surface and provide improved visual acuity.


Keratoconus is a fitting challenge for even the most experienced practitioner. Each case is unique and requires a strong rigid lens background with good fluorescein evaluation skills. Conforma-K lenses will provide the design and material combination that will reduce the challenge and increase your success rate. Conforma-K lenses are only available in the Boston ES® and Boston XO® materials. These proven materials will provide the oxygen delivery, wetting and stability essential to maximizing on-eye performance. The Conforma-K geometry enables efficient masking of irregular corneal astigmatism, typical of most conic corneas. The Conforma-K geometry provides a series of aspheric curves that progressively flatten from the paracentral section to the most peripheral area of the lens. This progressive flattening minimizes localized pressure points resulting in an improved lens to cornea fitting relationship. Better fit and alignment means improved comfort and physiology.




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A trial fitting is essential for your Keratoconus patient. If your patient is not wearing a GP lens, you will have to rely on Topography or Keratometry findings to select an initial trial lens.


  1. Select a base curve .50 diopters flatter than the average "K"

    Example:Keratometer ReadingsBase Curve
    45.00 / 50.0047.00 (7.18)
    This is only a suggested starting point. Traditional keratometry readings can serve as a reference but are usually of little value in determining the final base curve selection. The keratometer measures approximately 3mm of the central cornea. The cone is normally inferior and generally much steeper than the central and superior sections of the cornea. A successful fit must be based on your observations of the fluorescein pattern, lens movement, position and visual acuity. A gross observation of your trial lens should be made to evaluate general position and movement. Low riding lenses are not uncommon on cone patients and should not be rejected based on position alone. If the lens is generally centered over the pupil and lens movement is not excessive, you are now at a point where a more critical evaluation should be accomplished with a Burton or Slit lamp. Acceptable lens position and movement would maintain the visual axis within the optical zone. Decentration or movement resulting in an interruption in vision, would not be acceptable.
  2. Observe Central fluorescein pattern. Minimal clearance to light touch at the apex of the cone should be the objective.
    Fluorescein should be used to closely evaluate the fitting relationship of your trial lens. An acceptable fluorescein pattern would show minimal clearance to light touch at the apex of the cone. A three point touch would be acceptable, light touch at the apex and mid-periphery.
    Adjacent to the cone, fluorescein will generally form a surrounding band of pooling. This pooling should begin to thin as the lens surface comes into closer alignment at the mid-cornea. 360 degrees of peripheral edge lift should be present with no seal-off points. Apical touch should be minimized.
  3. A flat fitting lens could display any or all of the following symptoms.
    1. Harsh or broad area of apical touch.
    2. Excessive peripheral stand-off or pooling.
    3. Excessive movement or displacement with blink.

    If your trial lens demonstrates any of the above symptoms, begin steepening the base curve in 0.50 diopter steps as required. Diameter and peripheral curve changes will also influence lens fit. Call consultation to discuss your options.
  4. A steep fitting trial lens could display any or all of the following symptoms.
    1. Excess apical clearance or central pooling.
    2. Trapped bubble adjacent to the cone.
    3. Mid-peripheral or peripheral seal-off.
    4. Lack of lens movement.

    Base curve flattening in 0.50 diopter steps will be your most effective change to loosen a tight fitting lens. A diameter or optic zone reduction, as well as a flatter peripheral curve, could be used to loosen a tight fitting lens.
  5. Over-refraction
    Once an acceptable fit is achieved, over-refract to determine the final lens power. Residual cylinder may be present, but all attempts should be made to avoid complex toric designs. Whenever possible, your best spherical over-refraction should be used in determining the final lens power.



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The posterior surface of the Conforma-K design flattens progressively from the para-central section to the edge. A series of aspheric curves provide an improved lens to cornea relationship by minimizing localized pressure points. The Conforma-K design will enable you to more efficiently fit irregular astigmatism and conically shaped corneas.

Conforma-K Trial Sets (27 Lenses or 15 Lenses)
Materials:Boston ES®
Boston XO®

Conforma-K Diagnostic Set (27 Lenses)
Base Curves:7.60 - 5.00
Power:-5.00 to -9.00
Diameter:8.0, 8.5, 9.0

Conforma-K Diagnostic Set (15 Lenses)
Base Curves:6.90 - 5.50
Power:-7.00
Diameter:8.5

Option #1
Conforma-K GP Lens Trial Set - Purchase with Rebate


Fitting set use saves time and offers assurance that a given design is likely to work. Conforma offers a rebate program designed to eliminate the cost concerns of Diagnostic Sets.


Option #2
Conforma-K GP Lens Loaner Set Program


Loaner Set Option - 27 lens Diagnostic Set
Loan Period: 30 days
Handling Fee + Postage: Call for details
(note: handling fee applied toward purchase price if you decide to keep the set.)




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If you would like a consultation on a specific case, email topography and corresponding patient data to: info @ conforma.com or Fax 1-800-423-8706. Conforma now has a fax machine that can receive and print color topographical maps. Please provide your contact information: name, phone number and Conforma account number for a quick response to your request. You can also call consultation at 800-426-1700.