Kerarings also called ‘corneal implants’ or ‘intra-corneal ring segments’ are a surgical treatment for keratoconus. The small, clear semi-circular rings are inserted at the edge of the cornea. They flatten the distorted cone shape of the cornea returning it to a more normal curve, improving vision so glasses and/or contact lenses are easier to tolerate. 

What is keratoconus?

Keratoconus is a condition that results from an irregularly shaped cornea, which prevents light from focusing correctly on the retina. In keratoconus the normally round cornea becomes thin and more cone-shaped causing blurred vision and sensitivity to bright lights.

What are the symptoms of keratoconus?

People who have keratoconus experience distortion of their vision including multiple images, sensitivity to light and ‘streaking’. The amount of visual distortion can vary between eyes.

What causes keratoconus?

Keratoconus usually develops between the ages of 10 and 25 years and although the exact cause is unknown, there may be a genetic origin. About 15% of patients have a family member with the condition. Excessive eye rubbing could be a contributing factor and people with allergies or eczema may be prone to developing keratoconus due to a high occurrence of rubbing their eyes.

How do you treat keratoconus?

Your ophthalmologist will review your medical history and do a regular thorough eye exam. They will take images of your cornea to determine its shape and to measure the corneal thickness (topography) and take the intraocular pressure. These tests confirm if you have keratoconus and also monitor the progresssion.

The first treatment options are glasses or rigid gas permeable (hard) contact lenses for people with mild keratoconus. When glasses are no longer correcting the vision or the cone shaped cornea can no longer tolerate the hard contact lenses, Keraring corneal implant surgery may be of benefit. Sometimes Keraring implant surgery is done with corneal cross linking.

What are Kerarings?

Kerarings also called ‘corneal implants’ or ‘intra-corneal ring segments’ are a surgical treatment for keratoconus. The small, clear semi-circular rings are inserted at the edge of the cornea. They flatten the distorted cone shape of the cornea returning it to a more normal curve, improving vision so glasses and/or contact lenses are easier to tolerate. Sometimes your surgeon will use Kerarings together with corneal cross linking to achieve further stabilisation of the cornea.

Keraring corneal implants are removable and replaceable. If the Keraring is removed, your cornea will go back to its original cone shape.

Kerarings were approved in 2004 by the Food and Drug Administration(FDA) for people with keratoconus who cannot adequately correct their vision with glasses or contact lenses and for who corneal transplant is the only other option.

Am I suitable for Keraring surgery?

Kerarings are best suited for people diagnosed with mild to moderate keratoconus who have the following visual symptoms:

Moderate to high short-sightedness (myopia)

Severe astigmatism

Irregular astigmatism

No longer benefiting from wearing glasses or contact lenses

Have become intolerant to wearing rigid contact lenses

What is the goal of Keraring surgery?

Keraring corneal implant surgery has the goal of improving your visual acuity by:

Flattening the bulge of the cornea

Making the corneal surface more regular to improve your vision

Reducing myopia and astigmatism

Improving the tolerance and comfort of wearing contact lenses

What to expect during Keraring surgery

Keraring surgery is done as an outpatient day surgery and you will be awake during the procedure.

Keraring surgery is minimally invasive and normally takes around 30 minutes. You can have both eyes done on the same day.

A mild sedative will be offered to help you to relax.

Before your surgery you will be given anaesthetic eye drops to numb your eye. A small instrument will be placed between your eyelids to prevent you from blinking.

Your ophthalmologist will use the femtosecond laser to make a tiny and incredibly precise circular channel within your cornea. Your corneal implants (kerarings) will then be carefully inserted into the channel and the incision will close and heal naturally, without the need for stitches.

You will only feel some pressure on your eye for around 30 seconds.

What to expect after Keraring surgery

After your surgery you will be given eye shields to wear to protect your eyes as they heal.

You will be given antibiotic and anti-inflammatory eye drops to use for at least a week to help you heal and to prevent infection.

You will need someone to drive you home after the procedure and to return to the clinic the next day for a check up. Your ophthalmologist will follow up your progress again in two weeks, and then two months.

Most people can return to normal activities in 2 to 3 days. For two weeks after the surgery you should avoid heavy lifting and stay away from dirty, dusty environments. You’ll need to keep the area dry, showering is fine, but no swimming due to the risk of infection.

Your doctor will let you know when it is ok to drive again.

Will I need new prescription glasses or contact lenses after Keraring surgery?

You will most likely notice an immediate improvement in your vision after keraring surgery, but we advise you to let your vision settle for around three months before being fitted for new glasses or contacts.

Are there any risks in having Keraring surgery?

Kerarings are a very safe procedure as no corneal tissue is removed.  The risks are low and only minor if they do occur. Infection rates are low, but like all surgical or medical procedures there is always a risk of a complication. Your ophthalmologist will discuss all known risks and complications with you at your assessment.

Contact Bowen Eye Clinic on 0800 69 2020 to learn more about your keratoconus and a management plan for you.