Available options for keratoconus management

Available Options For
Keratoconus Management
BY
Dr. Amr Mounir , Lecturer of Ophthalmology
Sohag university

Definition
Keratoconus is a
progressive,
noninflammatory,
bilateral (but usually
asymmetric) ectatic
corneal disease,
characterized by
paraxial stromal
thinning and
weakening that leads
to corneal surface
distortion..

Etiology
-History of trauma that causes
weakness
-Recurrent trauma due to rubbing
from
Blepharitis, Vernal keratoconjuctivitis
-Inflammatory component!!!
Decrease proteinase inhibitors
Increase collagenase
Premature keratocytic apoptosis
Increase cytokine binding

Pathology
--Epithelial
basement
membrane
fragmentation and
scarring
--Axial stromal
thinning and
scarring
-Breaks in and folds
close to the
Descemet
membrane result in
acute hydrops

Clinical Picture
Patients with keratoconus (KC) often
report decreasing vision (distortions,
glare/flare, and monocular diplopia or
ghost images), with multiple
unsatisfactory attempts in obtaining
optimum spectacle correction

Signs
-Decrease in visual acuity
-Progressive myobia ,irrigular
Astigmatism
-Oil droplet sign by direct
ophthalmoscope - irregular
scissoring by retinoscopy

Slitlamp findings
FLEISCHER RING abrupt change in curvature
VOGT’S STRIAE 1st
Sign
STROMAL THINNING
STROMAL SCARS
ENLARGED CORNEAL NERVES
ACUTE HYDROPS

Investigations
1-Old methods:
A- Placido Disc
B- Retinoscopy
2-New Methods:
A- Corneal topography
B- Pentacam

What Pentacam says to us???
1-Pachymetry map
2-Keratometry map ( K1,K2,Kmax(
3-Cone site and shape
4-Elevation map
5-Provisional diagnosis: Keratoconus
Summary ( Sirus device(
6-Aberration map
7-Scheimpflug imaging

Classifications of
keratoconus
Several classifications of keratoconus
based on:
1-Morphological Patterns
2-Topographical Patterns

Topographical Patterns
Krumeich Classification of
Keratoconus:
Severity of KC is also classified by Krumeich.
This classification depends on mean K-
readings on the anterior curvature sagittal
map, thickness at the thinnest location, and
the refractive error of the patient.

Forme Fruste Keratoconus
Forme Fruste Keratoconus (FFKC(:
is a subclinical disease and is not a
variant of KC. Although clinicians use
many other terms such as mild KC,
early KC, and subclinical KC

Recently, there are two opinions
regarding the definition of this disease:
1.FFKC is a completely normal cornea
with neither clinical nor topographical
risk factors, but this cornea is able to
develop KC when treated by laser.
The fellow eye may be keratoconic or
there may be a family history of KC

2.FFKC is an abnormal cornea. Corneal
topography or corneal hysteresis or
both are abnormal; i.e., there are risk
factors but the case is still not a
clinically obvious KC.

Pellucid Marginal Degeneration (PMD)
and Pellucid-like Keratoconus
-PMD is a bilateral, non-inflammatory,
peripheral corneal thinning disorder
characterized by a peripheral band of
thinning of the inferior cornea. The
cornea in and adjacent to the thinned
area is ectatic.
-Patients usually are aged 20–40 years
at the time of clinical presentation.

Options For Treatment
Depend on:
1-Age
2-Refraction
3-Pachymetry
4-Keratometry
5-Cone Position
6-Corneal Opacifications.

Options
1-Glasses and follow up.
2-Hard Contact Lens.
3-CXL ( Transepithelial – Epi-off(.
4-Rings ( Kerarings- Myoring(.
5-Keratoplasty(Lamellar – penetrating(

Rules in treatment
1-Non of treatment options is satisfactory for the
patient.
2-The disease is progressive by its nature.
3-Follow up is mandatory.
4-Combination of treatment options can be done.
5-Keratoplasty can be a final destiny even with
treatment.
6-Rings mostly will be followed by glasses.
7-Don't judge on improvement of VA without correction.
6-Financial aspect should be taken into consideration.

Glasses and follow up
When?????
1-Age > 28 ys old.
2-Stable and low refraction with BCVA
>6/24
3-Clear cornea
4-Favorable Pentacam:
1(Average Keratometry <46 Ds
2(Thinnest Pachymetry > 480 um

Hard Contact Lens
--GP lenses are not the same as the
old hard lenses. For one thing, GP
lens materials allow oxygen to pass
through the lens and reach the
cornea.
-With advances in manufacturing, GP
lenses are made in thinner designs,
larger diameters, and with more
consistently smooth edges than ever
before.

-GP contact lenses are custom made for
each individual.
-Parameters which are needed for GP
contact lens request.
1(Keratometry: for initial fitting
2(Refraction.

-Soft lenses do provide better initial comfort,
while GP lenses require a brief adaptation
period. But this is due to the size of the
lens — not the lens material.
-Soft lenses are larger in diameter than GP
lenses and "tuck under" the eyelids. As a
result, you don't feel the lens edges when
you blink. But since GP lenses are smaller,
during blinking your eyelids will experience
initial "lens awareness.

Hybrid lenses
This is a lens design combination that
has an RGP center surrounded by a
soft peripheral “skirt”. Hybrid contact
can provide the crisp optics of a GP
lens and wearing comfort of soft
contact lenses. They are available in
a wide variety of parameters to
provide a fit that conforms well to the
irregular shape of a keratoconic eye.

CXL (Transepithelial – Epi-off(.

Why CXL is important???
-The only actual therapy for
keratoconus.
-Main effect is stiffening and flattening.
-Long term effect.
-Minimal optical effect.

1-Transepithelial CXL
Important hints:
-Less effective than Epi-off.( Less
flattening effect(
-Less complications rate.
-More comfortable for the patient.

When to do?????
-Early Keratoconus. 46 Ds<Mean K <
48 Ds
-Middle aged patients.
-Very thin corneas.
-After ICRS.
-Inadequate follow up.

2-Epi-Off CXL
When to do???
-In moderate and advanced cases.
-In young patients < 25 ys old.

Ideal patient for rings
-High errors.
-Mean Keratometry > 48 Ds
-K Max > 50 Ds
-BCVA < 6/30
-High patient motivation

Kerarings
-Non central cones.
-High cylinder.
-High difference between K1, K2.
-Thickness at insertion site >400 um

Pre and post Kerarings Pentacam

Myoring
-Central cones ( Nipple ,Oval , Globus(
-High K readings K1, K2 with low
difference.
-High errors with high sphere.
-Thinnest location > 400 um.
-Epi-off like CXL.
-Eye without refraction.

Central cone - Refraction : -8 Ds -7 Dc
-Very high K readings For Myoring implantation

-Shifted cone , Refraction : -9Ds -4.5 Dc
-K2 @ 68 For Kerarings implantation

When to do???
With Myoring:
-It should be done in the same session
( intrapocket CXL(.
-Epi-off like effect as it crosses the epithelium
With Kerarings:
-It should be done in the same session or after
ring implantation not before.

Age as a guideline for decision

Young age < 25 ys ---------- be
more aggressive
Early Keratoconus: Epi-off CXL
stabilization and follow up
Moderate and severe Keratoconus:
CXL  stabilization + Rings 
Regularization and Flattening
Advanced opacified cornea :
Keratoplasty

Middle age > 25 ys ---------- be less
aggressive
Early Keratoconus: Epi-on CXL or follow
up
Moderate and severe Keratoconus:
Rings  Regularization and Flattening with
follow up if progression  Stabilization by
CXL
Advanced opacified cornea :
Keratoplasty

Aim:
-To delay corneal grafting.
-To make the eye refractable.
-To decrease coma aberrations.
N.B: Keratoplasty is still an option

Home message
-Many guidelines affect our decision in
keratoconus management.
-Pentacam is an important tool in evaluation
of Keratoconus patient.
-Age is a guiding factor in treatment with
aggressive attitude in young age.
-Customization should be done for every
patient in keratoconus management.

Available options for keratoconus management

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