KERARING ™ INSTRASTROMAL CORNEAL RING
HALTING THE DEBILITATING EFFECTS OF KERATOCONUS
What are corneal rings?
Corneal rings are curved pieces of perspex designed to be placed at a precise depth within the cornea. They were originally developed to treat myopia – the placement of a ring in the mid-periphery of the cornea causes flattening of the central part of the cornea.
There are two kinds of corneal ring available – Kerarings ™ and INTACs. Kerarings have been specifically designed to treat keratoconus and we’ve found them very safe and effective. We no longer use INTACs.
Apart from keratoconus, Kerarings ™ also treat
- Pellucid marginal degeneration
- Post-LASIK ectasia
Who do Kerarings ™ help?
Kerarings ™ are particularly beneficial for treating mild to moderate keratoconus. Research we conducted at Leeds Teaching Hospitals demonstrated that 95% of patients with mild to moderate keratoconus benefitted from Keraring ™ implantation.
The results were less predictable for advanced keratoconus but still worth considering in patients who would otherwise need a corneal transplant to restore vision.
How do you treat keratoconus?
James Ball explains the different treatment options for treating keratoconus, including corneal cross-linking, intrastromal corneal rings and how he’d like to make corneal transplants for keratoconus no longer needed.
How do Kerarings ™ work?
The short answer is that no one is entirely sure.
Based on our studies we think that the following mechanism is the most important. The Keraring ™ seems to be most effective when it is able to bridge from stronger cornea through the cone to stronger cornea on the other side. A bit like an RSJ (rolled steel joint) used in building. The ring pulls the cone back in line with the rest of the cornea and lifts the steepest part of cornea onto the visual axis. This means that the part of the cornea which the patient is looking through is more regular and is able to give them better vision.
Advantages and disadvantages of Kerarings ™?
Keraring ™ is a rapid and painless treatment. We use a femtosecond laser to make a precise tunnel in the cornea. This takes just 8 seconds. We then slide the Keraring ™ segment(s) into the tunnel. This takes a couple of minutes. The whole procedure usually takes just five minutes.
Keraring ™ has a rapid recovery. The eye may be a little sore and scratchy the evening of the treatment but settles very quickly. Any improvement in vision is usually evident within a few days but may take up to three months.
Keraring ™ is reversible. If the Keraring ™ does not provide any improvement it can easily be removed and the cornea returns to its previous state.
Keraring ™ has less predictable results for advanced keratoconus. Some patients experience a mild glare effect from the Keraring ™ in certain light conditions, although this settles over time.
Options and alternatives to Kerarings ™
Spectacles and contact lenses can work well for mild to moderate keratoconus.
Keraring ™ implantation does not prevent progression of keratoconus. In many patients, the keratoconus stabilises with natural age-related cross-linking but many patients, particularly younger patients may require C3-R cross-linking treatment.
Some patients may benefit from toric phakic IOL implantation after Keraring ™ implantation in order to unlock further improvement in vision.
Further information about Keraring ™ treatment
At the preliminary Examination
A preliminary examination and measurement of your eyes is performed. This examination lasts about two hours.
Before this preliminary examination you should not have worn soft contact lenses for one week, and hard contact lenses for two weeks.
On the Day of Your Keraring ™ Treatment
We recommend that you wear comfortable clothes on the day of treatment. You can eat and drink normally on the treatment day, but please do not smoke. For hygiene reasons, it is important that you wash your face thoroughly prior to treatment, completely remove makeup, and avoid perfume.
You will be given anaesthetic eye drops to numb the surface of the eye, and you should feel no discomfort during the procedure. The surgery will be carried out as an outpatient procedure. Sunglasses are recommended after the procedure.
The total duration of the surgery (one eye) lasts approximately 10-15 minutes.
You are not allowed to drive a vehicle after the procedure.
The Keraring ™ Procedure – Step by Step
First, a tunnel is prepared in the cornea for the ring to be inserted into. At St James, we use the femtosecond laser – which makes the precise incision within 16 seconds.
The ring is inserted into the tunnel, and carefully positioned. The rings “tighten” the corneal cone and creates a more regular corneal surface.
After the Keraring ™ Surgery
The eye can be a little red – please do not rub your eyes. Eye drops will be given that prevent swelling and inflammation. The use of the eye drops will be discussed with you before you leave.
You can return to work after 2 days, resume sports activities after approximately 3 days, swimming and sauna after approximately 2 weeks.
You will receive a post-operative follow-up examination after 1 day, 1 week and 1 month.
You may drive a vehicle again only with the doctor’s permission, normally after the first post-operative examination.
Frequently asked questions about Keraring ™
A Keraring ™ is an artificial ring, which consists of two semicircular segments 5mm in diameter and of variable thickness. The ring is made out of artificial material, Perspex CQ Acrylic, which is the same material used for more than 20 years for artificial lens implants in cataract and refractive lens exchange surgery. The Keraring ™ is tolerated well by the cornea and no risk of rejection exists. The main reason for the surgery is an improvement in vision. Kerarings can halt the progression of keratoconus and prevent the need for a corneal transplant. Once the Keraring is in place a crosslinking procedure can be performed to stabilise the cornea, usually 2 to 3 months later.
In some patients, the Keraring ™ may improve the contour of the cornea, but not produce a significant improvement in the quality of vision even with a change of glasses or contact lenses.
The risk of a serious complication causing visual loss, such as an infection, is less than 1 in 1000. Complications are generally not severe, but if they do occur, the Kerarings ™ may need to be removed.
Despite Keraring ™ surgery, a corneal transplant may still be necessary in some cases.