Collagen Cross-Linking

COLLAGEN CROSSLINKING : A PARADIGM SHIFT IN KERATOCONUS MANAGEMENT

This revolutionary new treatment offers a new hope in patients of progressive Keratoconus

Keratoconus is a bilateral ocular disorder in which the cornea assumes a conical shape due to thinning of the stromal collagen tissue.It is a relatively frequent disease with an incidence of 1 in 2000 in the general population.It classically has its onset at puberty and is progressive until the third or fourth decade of life when it usually arrests.

Keratoconus can be detected clinically by slit lamp examination by an Ophthalmologist and the diagnosis can be confirmed by corneal topography.

Treatment options

Currently, the mainstay of treatment for Keratoconus include glasses and / or specially designed rigid gas permeable contact lenses which offer good quality of vision in advance cases keratoconus can be corrected surgically by corneal grafting and placement of intracorneal rings. However, all these treatment options only correct the refractory error in Keratoconus and do not address the issue of progression of the disease. Collagen Cross Linking is a new modality of treatment that aims to arrest progression of keratoconus.

What is Collagen crosslinking ?

The corneal collagen is crosslinked with the help of ultraviolet rays ( UVA ) and a photosensitiser, Riboflavin , thus enhancing the rigidity of corneal tissue and stabilizing the condition

Who is a suitable candidate for Collagen crosslinking ?

Patient must be a proven case of keratoconus with documented progression of the disease.
Patient's corneal thickness must be at least 400 microns.
Patient should not be pregnant or nursing.

How is Collagen crosslinking performed ?

The treatment is performed under topical anaesthesia with the patient in a lying down posture in the sterile environment of the operating room. The patient's corneal epithelium is gently removed, following which Riboflavin solution is applied every 5 minutes for the first half an hour. Thereafter the patient's cornea is exposed to UVA light for half an hour. The treatment is painless and lasts for an hour, at the end of which the eye is patched. The cornea is the clear, transparent dome in front of the "black portion" of the eye. It is also the main focusing surface, which converges light rays as they enter the eye to focus on the retina. It is thus the most important part of the optical apparatus of the Eye. Loss of transparency directly results in loss of vision.

When can the patient resume normal routine ?

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.The use of contact lenses may be resumed 6 weeks after treatment.

How often must the patient come for follow up ?

The surgeon will examine the patient's eye daily for the first 2 to 3 days until the epithelial healing is complete. Eye drops will be used for 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 ophthalmologist.

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 the 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.

Concerns using UVA light

UVA light can potentially harm the vital cell layer of the cornea known as the endothelium as also the crystalline lens and the retina. However, the use of riboflavin and the choice of the wavelength of UV light used, substantially reduces the intraocular penetration of UV rays to negligible levels. Potential side effects are therefore avoided. It is mandatory to perform a preoperative measurement of the corneal thickness and to exclude patients with corneal thickness less than 400 microns .

The 3 & 5 year results of the Dresden clinical study on collagen crosslinking in human eyes has shown arrest of progression of keratoconus in all treated eyes Collagen crosslinking has thus emerged as a safe and effective , inexpensive non surgical promising new treatment for Keratoconus to slow the progression of the disease and to delay or avoid corneal graft surgery. With more long term experience in the arena , prophylactic treatment of Keratoconus might become possible with collagen crosslinking.