and Treatment with Contact Lenses
condition whereby the cornea gradually thins and becomes misshapen.
The cornea surface becomes irregular similar to the shape of a cone
from the pressure of the eye causing vision loss. The cornea is the
clear "window" part of the eye, in front of the pupil and
colored part of the eye, called the iris. The vision resulting is
similar to looking through an ice cube. Although the cause of Keratoconus
remains unknown, biologic and metabolic changes to the
cornea have been observed. Incidence amongst the population is about
1 out of 2,000 to 4,000. Family histories of Keratoconus have been
reported with an incidence of less than 1 - 2%. Cases of Pellucid
Marginal Degeneration which is similar to
Keratoconus , but
has a wider thinning of the cornea has been documented in families
with a slightly higher incidence.
Causes Irregular and Oblique
Astigmatism - The trademark
shape is the pointy and irregular shaped cornea.
in teenage years, from thirteen to fifteen years of age, but
generally starts later in the low to mid twenties. Many mild cases
of Keratoconus go undiagnosed. Eyeglasses or soft contact lenses can
correct early stages of Keratoconus . In later stages of the disease,
Vision can become blurred within a few years whereby driving vision
can not be attained without treatment. Untreated advanced cases past
five years can result in blindness.
* With the advent of
Laser Refractive Corrective surgery, many cases of Keratoconus
being diagnosed with the associated consultation. Laser Refractive
Corrective surgery can not be performed on an eye with Keratoconus
due to the thinness of the cornea.
Early onset of Keratoconus
years can progress rapidly and cause the cornea to become conical
within a few years time span. Keratoconus with teenage onset can
advance to include scarring and Neovascularization of the cornea.
Neovascularization is a condition where blood vessels grow into the
cornea from the cornea thinning causing vision impairment.
If vision loss is significant, a
Keratoplasty (cornea transplant) may have to be performed. If
Neovascularization is present, transplantation of a new cornea can
have rejection difficulties. Use of immunosuppressants have
been known to be successful to avoid rejection difficulties.
More common is later onset of
Keratoconus . Keratoconus onset in your twenties generally does not progress as
rapidly and many times stabilizes before thirty years of age. Individual
cases can vary and many will have normal vision with the use of
specialized contact lenses and some vision with the use of
eyeglasses. In extreme cases where the cornea is scarred, and a
specialized contact lens can no longer restore vision, a corneal
transplant may be required.
In the past Keratoconus
was often a
blinding disease. Today, treatment has improved with many advanced
contact lenses available. In the past fifteen years, we have treated
hundreds of Keratoconus patients with C-Kone contact lenses allowing
them normal vision. We have found that fully 90% of all Keratoconus
patients have had success wearing C-Kone contact lenses producing
adequate vision and many times 20/20 vision. Transplantation of
corneas has become an extremely rare vision correction requirement.
Fittings of Keratoconus
require several visits over a period of 2 to 8 weeks. More difficult cases can take 3 to 9 months for a complete
The proper spelling is "Keratoconus",
to enable improper spellings to access this web-site on search
engines, some alternative misspellings are
keratconus, ceratoconus, cerataconus, ceratakonus and ceratokonus.
3-D Topographic Map
The above map shows the
topography curvature of the cornea of an eye with an advanced state of
Keratoconus . The red areas depict the steeper "cone
shaped" areas of the corneal
curve and show the irregular shape of the cornea surface. At Lens
Design Ltd., we use "state of the art" cornea mapping
technology to assure that your contact lens fitting is maximized.
Wearing eyeglasses would not be an option for an eye such as this.
This patient was fit with a special C-Kone gas permeable contact
lens and vision was restored to 20/25.
C-Kone contact lens
C-Kone lenses are gas permeable
contact lenses specially designed for the treatment of Keratoconus .
They are fitted from a fitting kit that allows perfect duplication
of size. The design of these lenses mimic the shape contours that Keratoconus
presents. After treating Keratoconus for twenty years and cataloging
all the variable shapes, we have defined quite precisely what shapes
that are required. The shape is cut into the contact lens using a
state of the art Coburn lathe with aspheric curve generation.
Aspheric curves are like a stair case with no sharp step edges. The
lens material that we currently supply is Boston XO. This lens
material has superior oxygen transmission. C-Kone lenses are 9.6
millimeter in diameter and each have a 6 millimeter optic zone. This
allows full vision even in low light settings. Precise definition of
fit, maximized optic zone and breathing of the lens all add up to a
beautifully comfortable lens with excellent visual results.
C-Kone contact lens features
- Multi - curve aspheric fitting
that is computer contour blended
- Large optic zone for superior
- Large "foot pad" for
increased comfort for long days
- Excellent night vision, no glare
- Good movement for tear exchange
- Expandable for wide range of
- Will fit advanced stages of
- High oxygen material for cornea
Other contact lens corrections
Primary correction of
with gas permeable contact lenses. Other
types of contact lenses for the correction of Keratoconus include:
- Soft contact lenses designed
specifically for Keratoconus
- Piggy back soft contact lenses to
"carry" a gas permeable lens
- Softperm lenses - a soft lens with
a hard center
- Scleral contact lenses that cover
a large portion of the cornea
- Synergeyes KC - New high oxygen
transmission hybrid soft lens with a gas permeable center
specifically designed for Keratoconus
- Novakone - New
soft contact lens designed specifically designed for Keratoconus More
Surgical treatment options
- Cornea Cross Linking (C3R) - is a
procedure that was developed in Germany. The procedure consists
of using UV light with Riboflavin (vitamin B2) in an
attempt to bond the structural layers together to increase
strength. There are currently studies being performed in North
America to determine the efficacy of this procedure.
- Intacs - are plastic
strips that are implanted into the cornea to help reshape the
- Cornea transplantation - is
performed when the vision can no longer be restored with contact
lenses. Cornea transplants replace the window of vision to allow
light to pass through again.