Hasan A. Mokbel
Contact Lens Department
What is Keratoconus ? (causes, types, related
Management of Keratoconus/ available
Rose K family
Keratoconus is a degenerative disorder of the eye in which
structural changes within the cornea cause it to thin and
change to a more conical shape than its normal gradual
Tiny fibers of protein in the eye called collagen help hold
the cornea in place and keep it from bulging. When these
fibers become weak, they cannot hold the shape and the
cornea becomes progressively more cone shaped.
Classification can be according to :
1. Nipple Shape ( small size 5 mm)
2. Oval cone ( 5 to 6 mm )
3. Globus ( large , may involve 75 % of the cornea )
Severity of curvature :
1. Mild ( 45.00D)
2. Moderate (45.00 – 52.00 D)
3. Severe ( more than 52.00 D)
a form of retinal dystrophy
An abnormally thin and flat cornea
genetic disorder caused by the presence of all or part of a third copy of
At the early stages of Keratoconus spectacles and soft lenses
are used to correct vision.
With the progression of the disease majority of the patients
will use rigid contact lens.
The very latest contact lens for treating Keratoconus is the
synergize hybrid contact lens which is rigid at the middle and
soft at the edges.
RGP lenses provide good treatment by resurfacing the
irregular cornea and corrects astigmatism and provide
good vision quality.
The majority of patients who used RGP witnessed a
Patients with contact lenses suffer mainly from
uncomfortable long period wear due to dryness of the eye
since there's no lubrication to prevent evaporation.
The Rose K lens was invented by Paul Rose, an optometrist
from Hamilton, New Zealand.
Rose k lenses were made with complex geometry to fit any
type of cone shape cornea.
The Rose K family includes :
1. Rose K/K2
2. Rose K2 post graft
3. Rose K2 IC
4. Rose K2 XL
The optical zone is reduced to fit the cone
and the peripheral curve is designed to fit
the rest of the irregular cornea.
Lenses can be customized to suit each eye
and can correct the myopia and astigmatism
associated with the condition.
The Rose K lens has a number of features that make it
ideal for Keratoconus:
1. Its complex geometry can be customized to suit each eye and can
correct all of the myopia
2. They are easy to insert, remove and clean.
3. They provide excellent health to the eye, because they allow the
cornea to "breathe" oxygen directly through the lens.
4. Practitioners have the Rose K trial set fitting system which achieves a
first fit success in over 80% of patients internationally.
5. They correct myopia and astigmatism associated with Keratoconus.
Rose K2 is a refined Rose K lens which takes into account
the unusual corneal shapes of Keratoconus patients, which
require abnormal curves on the back of the lens to fit the
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.
Large parameter range available which makes fitting easier
and lowers the chair time.
Advanced aberration control
• Pellucid Marginal Degeneration - PMD
• Keratoglobus more than 75% of cornea is involved in the
• Post Lasik,Post Graft
• Same design as RoseK2 IC , reduced pool and reversed
curves to allow proper healing after surgery.
Rose K Post Graft Lens for patients who have undergone
penetrating keratoplasty. This lens is designed for
postoperative recovery and improvement in vision.
semi-scleral contact lens
designed to vault the corneal surface and rest on
the less sensitive surface of the sclera, these
lenses often are more comfortable for a person
with Keratoconus. Also, scleral lenses are
designed to fit with little or no lens movement
during blinks, making them more stable.
Indicated for indicated for Keratoconus, PMD, Post Graft,
and other irregular cornea conditions that cannot be
successfully fitted within the limbus.
much larger than conventional GP lenses and rest near the
junction between the cornea and the sclera.
1. Determine the corneal shape
2. Central fit
3. Peripheral fit
4. Overall diameter
6. Lens movement
Lens selection with a back central optic
radius ( BCOR) 0.2 mm steeper than the
mean K reading.
Central fit : leather weight touch to the
apex of the cone is desirable.
Peripheral fit : the peripheral fit should
have a Fluorescein edge width 0.5 – 0.7 mm
Overall diameter : the standard diameter is
8.7 mm but smaller diameter can be used
with steep cornea ( higher grade of
Location of the lens should be maintained
centrally ( any dislocation can be corrected
by changing diameter , edge lift and back
central optic radius (BCOR)
Lens movement with every blink the lens
should move freely across the cornea then
returns to its position and rests.
Determine the lens power by a carful over
refraction +/- 1.00 D and refine by 0.5 and
Vaults the irregular corneal forms
ClearKone® combines the best of both worlds – the crisp
vision of a high-oxygen rigid RGP contact lens with the all-
day comfort and convenience of a soft lens.
The ClearKone® fitting approach called
“vaulting” allows doctors to simply increase
the depth of the contact lens over the
cornea depending on how steep or severe the
individual patient’s Keratoconus
is. The ClearKone® vault system comes in 11
different choices and therefore can
accommodate even the most severe forms of
Steps of fitting :
1. Vault selection
2. Skirt selection
3. Determine Lens power
1. Vault selection :
Begin with 250µ Vault value in Medium skirt curve
Insert the lens filled to the top with saline and a drop of
high molecular weight Fluorescein.
Check for central bearing ,central pooling , or for
If central bearing is present then increase the vault by
100µ [ vault is too low ]
If central pooling is present then decrease the vault by
100µ [ vault is too high ]
2. Skirt Selection :
Always start with the medium skirt curve
The lens will exhibit movement very similar to a soft lens
The ideal fit will show thinning at the ILZ ( inner landing
zone ) and bearing in the OLZ (Outer Landing Zone)
3. Determine Final Lens Power:
If the over-refraction is greater than 4.00D
adjust for vertex distance