Corneal collagen cross linking CXL- A novel treatment for Keratoconus
This revolutionary new treatment offers a new hope for patients of progressive Keratoconus which can otherwise lead to severe vision loss ultimately requiring a corneal transplantation to restore vision. Corneal collagen cross linking is the only treatment till date to prevent progression of keratoconus. Studies have found that more than 90 percent of patients remain stable or achieve improvement in the corneal shape after crosslinking, which is highly significant for people with progressive keratoconus.
After treatment, patient still needs to wear spectacles or contact lenses to correct the vision as collagen crosslinking is done to halt the progression of the disease and does not correct the eye power. It is not a laser vision correction procedure to remove spectacles or contact lenses. Patients eyes can be sore for 3-4 days after the procedure. Although vision is often hazy at first, most patients can resume contact lens wear and return to work after one-two weeks.
Corneal collagen cross-linking (CXL) is a short day care procedure that strengthens the cornea if it's been weakened by keratoconus, other ectatic (where cornea protrudes like cone from rest of corneal surface) corneal disease, or (rarely) a complication of LASIK surgery. Alternative and brand names for the procedure include corneal cross-linking, collagen cross-linking, C3R, CCL and KXL.
The minimally invasive CXL procedure involves applying liquid riboflavin (vitamin B2) to the surface of the eye, this is followed by a controlled application of ultraviolet light. The two together helps in forming the cross-linkages between the collagen fibres which form the cornea thereby strengthening the cornea.
Corneal cross-linking also can be combined or preceded with other procedures for keratoconus treatment. For example, CXL can be preceded or combined with implanting tiny arc-shaped corneal inserts called INTACS. INTACS provide an additional advantage of regularising the irregular cornea which is a hallmark of keratoconus.
Who are suitable candidates for Corneal Cross-linking?
Corneal cross-linking is usually advised for progressive keratoconus ( corneal ectasia) cases. It is most effective if it can be performed before the cornea has become too thin or irregular in shape or there is significant vision loss from keratoconus or other causes of corneal ectasia. If applied early, CXL typically will stabilize or even improve the shape of the cornea, resulting in better visual acuity and an improved ability to wear contact lenses.
Other potential applications of CXL include the treatment of corneal ulcers that are unresponsive to treatment with topical antibiotics.
What to expect during and after a Corneal Cross-linking Procedure?
During preliminary examinations, your eye doctor will measure the thickness of your cornea and make sure you are a good candidate for the procedure. You also will need to have a routine eye exam to assess your visual acuity and general eye health. And your doctor will perform mapping of your cornea (called corneal topography) to determine the level of your eye condition.
The cross-linking procedure takes 30 to 45 minutes in most cases. In epithelial-off cross-linking, your surgeon will place you in a supine position. Anaesthetic drops are used to numb the surface of your eye before a small clip is placed to keep your eyelids open. Then the epithelial layer or top most layer from your cornea is gently removed. Riboflavin eye drops will then be instilled over every 2 minutes for the next 20 minutes. The corneal thickness will be checked, and then the UV light will be applied for a period of 10-30 minutes The duration of UV light application depends on the chosen fluence of the UV A light by the cornea surgeon.
Then a bandage contact lens will be placed. Topical antibiotic and anti-inflammatory drops will be prescribed.
Post – operative care:
The anaesthetic drops will wear off later on the day of your procedure, and your eye will be gritty, red and sensitive to light for few days. Everyone’s experience of pain is different, with some patients reporting very little discomfort and others describing the first few days as very painful. After the treatment, patient will be able to resume work within 3 to 4 days. Care should be taken to avoid entry of water into the eyes during this period.
Day to day activities such as watching TV or using a computer will not do any damage to your eye, but you might find it more comfortable to rest with your eyes closed early on.
How often to follow up?
The cornea surgeon will examine the patient's eye on next day and then 3 days later to see epithelial healing. Eye drops will be used for 3-4 months. Patient will have to come for follow up at 6 weeks, 3 months, 6 months, 1 year and 2 years after the procedure.
Can both eyes be treated at the same time?
If both eyes are suitable for Collagen crosslinking, the treatment is performed on one eye at a time. The timing of treatment of the second eye is best decided in consultation with your eye doctor.
What are the possible side effects of the procedure?
A foreign body sensation, irritation or watering accompanied by pain is not uncommon on the day of treatment. Analgesics for relief from pain will be prescribed, and pain usually subsides within 24 hours. Dryness of the eyes frequently follows this treatment and may last for 6 to 8 months. Tear lubricants are therefore recommended for the period. Very rarely more serious side effects like corneal infections, corneal haze, endothelium burns, corneal scar formation can happen.