Questions and Answers About The Keratoconus and know more about the C3R and more...
Understanding Keratoconus
Cornea is the outermost layer of
our eyes. It allows the rays of light to enter the eyes and then, focuses the
light rays on the retina for us to see. Thus, the impact of Keratoconus on our
cornea leads to worse eyesight.
Many patients of Keratoconus find
problems in carrying out some basic activities of day to day life. The simplest
of things for a person with a normal cornea, such as reading, watching,
driving, cooking, etc. becomes inconvenient for people suffering from
Keratoconus.
Causes of Keratoconus
Keratoconus is an inherited
condition that sometimes skips generations. Its onset is usually during puberty
and is often related to allergies (hay fever, asthma and eczema). The cornea is
a bit more elastic than normal and tends to alter in shape and thins out becoming
cone shaped. Rubbing the eyes can aggravate the condition.
Symptoms of Keratoconus
The typical patient with
undiagnosed keratoconus complains of deteriorating vision and frequent change
in glasses. They may often report multiple images or ghosting of images and
often relate a history of frequent refractive correction changes without much
improvement in visual acuity. Patients
may also report irritating symptoms such as intolerance to light (glare),
photophobia and a recurrent foreign body sensation.
Diagnosis Tests for Keratoconus
A complete assessment for keratoconus includes:
• Refraction and visual acuity
evaluation
• Intraocular pressure
measurement
• Slit lamp examination and
retina evaluation
• Corneal topography : Advanced
topography systems such as the Pentacam and Orbscan assess the overall
architecture of the cornea and help in early detection of keratoconus. These
tests are also important in assessing the progression of keratoconus and in
deciding the appropriate treatment options.
• Corneal Thickness measurement
(Pachymetry)
KeratoconusTreatment Options
There are two aspects to
keratoconus treatment - first we need to stop progression for which there is
only one treatment namely, C3R or corneal crosslinking.
Secondly, we look at the refractive
error treatment and see if there is any aid to improve vision. These options
include : spectacles, RGP contact lenses, special keratoconus contact lenses,
INTACS (intracorneal ring segments) and ICL. This decision as to what is best
suited from the above choices for your eyes can only be taken after a complete
assessment. Advanced cases with extreme thinning or scarring may not be
amenable to treatment with these modalities. A corneal transplant is required
in such cases.
• C3R/CXL - Corneal Collagen
Cross linking with Riboflavin
Corneal collagen crosslinking, CXL or C3R is a relatively new form of
therapy for keratoconus patients. This treatment is aimed at arresting the
further progression of keratoconus by strengthening the corneal architecture.
During the corneal crosslinking treatment, the superficial layer of
the cornea (epithelium) is removed. Custom-made riboflavin drops saturate the
cornea, which is then activated by ultraviolet light. This process has been
shown in laboratory and clinical studies to increase the amount of collagen
cross-linking in the cornea and strengthens the cornea.
Collagen crosslinking is not a cure for keratoconus. The aim of this
treatment is to arrest progression of keratoconus, and thereby prevent further
deterioration in vision and the need for corneal transplantation. Glasses or
contact lenses will still be needed following the cross-linking treatment
(although a change in the prescription may be required).
What to expect after
C3R/CXL?
After the procedure a bandage
contact lens is applied. You may experience pain, lid swelling and foreign body
sensation for 1-2 days after the procedure. The contact lens is removed 4-5
days after the epithelial healing is complete. Corneal haze develops in most
cases following C3R/CXL. This resolves significantly over 3 weeks and
completely over 6 months. The power of your glasses or fitting of contact
lenses may change initially for few weeks following the procedure. The final
prescription of glasses/ contact lenses is given 3-6 months following the
procedure.
• INTACS
Intacs are thin plastic, semi-circular rings inserted into the middle
layer of the cornea. The placement of Intacs remodels and reinforces the
cornea, eliminating some or all of the irregularities caused by keratoconus in
order to provide improved vision. This can improve uncorrected vision, however,
depending on the severity of the KC, glasses or contact lenses may still be
needed for functional vision. The channels for placement of INTACs into the
cornea can be created mechanically with a blade or with a precise femtosecond
laser. The use of the femtosecond laser has greatly enhanced the safety of the
procedure and improved surgical outcomes.
Intacs procedure may be performed in conjunction with C3R for improved
results.
• TORIC ICL
A collamer lens is implanted inside the eye to correct the refractive
error completely or partially. A toric ICL may be performed in addition to the
C3R procedure which aims to stabilize the refractive error.
• Corneal Transplant
In advanced stages - either a partial thickness (Deep Anterior
Lamellar or DALK) or full thickness (Penetrating or PK) corneal graft may be
required.
In keratoconus, a corneal transplant is warranted when the cornea
becomes dangerously thin or when sufficient visual acuity to meet the
individual's needs can no longer be achieved by glasses or contact lenses due
to steepening of the cornea, scarring or contact lens intolerance.
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