The Nicholson Eye Clinic helps evaluate and treat diseases of the cornea and epithelium, including dystrophies, infections, corneal swelling, dry eyes and Keratoconus.
What is keratoconus?
Keratoconus is a condition of the eye in which the structure of the cornea (the clear outer part of the eye)is not strong enough to hold its round shape, causing it to bulge outwards like a cone. Often, this condition is hereditary and occurs more frequently in people with certain medical problems.Progression of the outward corneal bulging can happen very quickly or can occur over several years, though these changes can stop at any time.
How Will Keratoconus Affect My Vision?
Keratoconus will change vision in two ways:
- Irregular astigmatism results as the smooth surface of the cornea becomes slightly wavy
- Nearsightedness develops as the front of the cornea expand
Symptoms
- Sudden change of vision in just one eye
- Double vision in just one eye
- Bright lights with halos around them
- Light streaking
- Seeing triple ghost images
The treatment is in the form of a surgical procedure called Collagen cross linking.
Collagen Cross Linking
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 ?
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 cross linking.