+917738273937The best candidate for CXL is a younger patient below age 30 who has early keratoconus or is at risk of progression
or has shown some progression. We want to diagnose keratoconus before it has advanced so much that it has
impacted the vision. CXL allows us to stop the progression of keratoconus but may not reverse the bulging of the cornea.
The patient who has very advanced keratoconus especially if the cornea is too thin is not an ideal candidate for CXL. Regardless, every patient who is younger is an ideal candidate for CXL because it is one of the most exciting treatment options available today.
WHAT IS KERATOCONUS?
Keratoconus causes the central area of the cornea to become thinner and weaker leading to an abnormal bulging or a cone like shape. The altered corneal biomechanics not only causes the tissue to protrude at the weakest point, but also significantly decreases the ability to see clearly as the light is distorted by the irregular cornea.
What are the Symptoms?
Common symptoms of keratoconus include:
• Blurred Vision
• Increasing Myopia
• Increasing Astigmatism
• Distorted Vision
• Glare
• Haloes around bright lights
• Poor vision not correctable with glasses or soft contact lenses
HOW DOES IT OCCUR?
The cause of keratoconus is unknown. It most commonly first becomes noticed during the teens to early adulthood and is more common in certain individuals, including those with significant allergy or “atopy” such as eczema and asthma. There are probably several genetic components (as cases often run in families) in combination with environmental factors, the most important of which is eye rubbing. If you have a family history of keratoconus or have been diagnosed with KC, it is very important not to rub your eyes because that can cause further progression of the condition.
WHAT IS THE DIAGNOSIS?
The diagnosis and severity of keratoconus is defined by subjective and objective measures. These include visual acuity (unaided, aided with glasses, aided with contact lenses); glare; ability to see and drive at night; ability to wear gas permeable or other contact lenses; cornea scarring; manifest refraction (strength of the glasses prescription); corneal topography (shape), pachymetry (central corneal thickness) and corneal tomography (front shape, back shape and global thickness).
HOW IS IT TREATED?
Modern treatment modalities for keratoconus are designed to stabilise the progression and improve the visual performance of the eye.
Current treatments include:
• Specialist Contact Lenses
• Corneal Collagen Cross Linking (CXL)
• Intrastromal Rings
• Topography Guided PRK combined with CXL
• Implantable Contact Lenses
• Corneal Transplantation
In the past, patients suffering from ectasia depended on treatment options such as rigid contact lenses or penetrating corneal transplants. However, these treatment options did not halt the progression of ectasia nor treat the condition at the root cause. The development of corneal collagen crosslinking 15 years ago, does have the potential to treat the underlying weakness of the cornea and stabilize the cornea.
HOW DOES CORNEAL COLLAGEN CROSS-LINKING WORK?
Our cornea naturally contains cross-links between collagen fibers in order to maintain shape and strength. Keratoconus is a result of fewer cross-links to support the cornea, leading to bulging and protrusion. Crosslinking utilizes a combination of riboflavin and UV light to create additional cross-links to promote cornea stability and strength. The corneal collagen fibrils are chemically bonded together to halt the thinning process and maintain corneal shape. This is a surface procedure and clinical trials have demonstrated that the strengthening effect may be permanent.
WHEN SHOULD CROSSLINKING BE DONE?
Drs. Sujal and Manisha Shah are experts who specialize in the management of keratoconus and corneal ectasia at every level of severity. The aim of treatment is to halt the disease and potentially reverse the impact on the vision. Any young patient diagnosed with keratoconus, especially with worsening disease, should be seen quickly and considered for collagen cross linking before the cornea thins to an extent that CXL cannot be done.
FREQUENTLY ASKED KERATOCONUS
Corneal collagen cross-linking is a technique that was first used in 1998 to treat patients with a disease called keratoconus. In keratoconus, the cornea (the front clear window of the eye) can become weak, thin, and irregularly shaped. Instead of keeping its normal round shape, corneas with keratoconus can bulge forward into the shape of a cone causing poor vision.
CXL is an in clinic procedure, the whole process takes about an hour where the first half of the procedure is putting drops or medicine allowing it to infuse on the tissue. The second half is exposing the cornea to a special UV light that will then lock the fibres of the cornea in such a way that it freezes it and strengthens it so that the process or progression of keratoconus is frozen at that time. We do epithelial off cross linking because that is the approved way.
During CXL, we remove the surface layer of the cornea after which the Cross-Linking is done. After that we use a contact lens to bandage the surface of the eye but since the surface layer is removed there will be discomfort or pain for the first two days after the surgery. Eye drops and pain medication will be prescribed to improve the comfort. The vision is blurry for the first 2 or 3 days until the surface heals which does eventually in a week. The vision may fluctuate for a couple of weeks. Patients go back to their work within the first week with some degree of limitations.
CXL is absolutely the most exciting new treatment out there for keratoconus. It has caused an absolute paradigm shift in how we address keratoconus. For patients who cannot tolerate contact-lens and conservative treatments it can stop the clock and as a result can prevent the need for corneal transplant. The success rate of CXL is upwards of 95%.
Rarely, if keratoconus continues to progress, CXL can be repeated and there is evidence that it could again slow down the progression of keratoconus or a corneal transplant can be done.
For patients with keratoconus, corneal topography is performed. This topography map is then imported into the CRS Master software. Dr Sujal and/or Dr Manisha will then plan a customised treatment to improve the corneal symmetry and address some degree of the refractive error. They will then evaluate if it is safe for your eye to undergo this topography guided correction. If this is possible in your case, you will be counseled accordingly. After, the topography guided surface ablation crosslinking will also be performed to stabilise the cornea that has been made more symmetrical by surface ablation, to preserve the effect of the treatment.
It is often possible to do this procedure for early to moderate keratoconus. The aim of the combined treatment is to make the cornea more regular and improve the quality of vision. It may not reduce or eliminate the refractive error.
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