Keratoconus Treatments
Dr Ang specialises in the management of keratoconus including collagen cross-linking to halt the progression of this disease.
What is keratoconus?
Keratoconus is a degenerative condition that affects the shape of the cornea, the clear window at the front of the eye. The cornea slowly changes from being round like a soccer ball to being shaped like a cone. This irregular shape causes short-sightedness and astigmatism which distorts and blurs your vision.
Keratoconus affects approximately 1 in 1000 people. It usually appears in the teens and early 20s and tends to stabilise by age 40. The exact cause is unknown but there is likely a genetic link as there is an increased rate if a family member has the condition. It is often associated with allergies and conditions such as hayfever, asthma, and eczema. The associated eye rubbing can make keratoconus worse.
How can Keratoconus be treated?
1. Stop eye rubbing
It is known that eye-rubbing can make keratoconus worse, and this is more likely an issue with people with hayfever and allergies. Using anti- inflammatory drops (Cromo-fresh, Zaditen or Patanol) or preservative-free lubricating drops can help reduce itching and eye rubbing.
2. Glasses or contact lenses
In milder cases, glasses can be effective in improving vision. Many patients with keratoconus require hard or rigid-gas permeable (RGP) contact lenses to see well. RGP lenses work by providing a smooth and evenly-curved front surface. Contact lens fitting for keratoconus requires skill and special equipment, and you need to see an optometrist with this expertise.
3. Collagen cross-linking
It is advisable for patients with worsening keratoconus to have collagen cross-linking (CXL). This procedure uses UV light and riboflavin to strengthen the bonds between the collagen fibres in the cornea. It thus stiffens and increases the strength of the cornea, stopping it from changing shape. This procedures does not improve the vision of the eye, but rather stabilises the condition from progressively getting worse.
What is involved with CXL?
This is a day surgery procedure that takes about 40 minutes. Dr Ang removes the epithelium using an excimer laser, and then yellow drops (riboflavin) are placed onto the cornea to soak through. The cornea is then irradiated with a blue light (UV-A) for 10 minutes. A bandage contact lens is placed on the eye and usually left in for one week until the surface heals.
Kerarings
Kerarings, also known as intracorneal ring segments (ICRS), are plastic rings that are inserted into the cornea to flatten and regularise the shape of the cornea. This may improve the quality of unaided vision or allow people to get back to having reasonable vision with glasses or contact lenses. These are not suitable if the corneas are too thin or steep, and the results can be somewhat unpredictable.
Corneal transplantation
Corneal transplantation may be required for those with severe or advanced keratoconus, where improvement of vision cannot be achieved with hard contact lenses. The diseased cornea is replaced with a healthy donor cornea and sutured into position (sutures are removed 12 to 18 months later). Deep anterior lamellar keratoplasty (DALK) involves replacing only the front diseased layers of the cornea, leaving the back healthy endothelial cell layer intact. This technique may reduce the risk of rejection compared to a full thickness corneal transplant. Please read more about corneal transplants here. (link to “corneal transplants page)