Intracorneal Ring Segments

Intrastromal corneal ring segments (ICRS) are semi-circular rings made of material similar to Perspex. They are placed in the cornea and change its shape. This is done to improve the vision achieved with glasses for sufferers of keratoconus and improves the patient’s tolerance to contact lens wear. The corneal shape improvement can mean that soft contact lenses rather than rigid lenses can be worn. Unfortunately in some patients, no effect is noticed by the patient. A recent study of Kerarings reported that vision with glasses or contact lenses was improved in 85%, unchanged in 9.8% and worse in 4.2%.

There are 3 types of corneal ring segments available: Intacs, Ferrara rings and Kerarings. Mr Wilkins uses Kerarings because there is some evidence that they have a greater effect than the other rings. He also finds that Kerarings do not interfere with future corneal graft surgery while Intacs do. The Keraring implant is transparent and very small. The aesthetic effect is similar to a contact lens and in most cases cannot be noticed by others with a naked eye.

The procedure

Keraring implantation is a relatively quick and painless outpatient procedure. The procedure usually takes about 20 minutes. The anaesthetic eye drops numb your eye and you will stay awake throughout the operation. The femtosecond laser is first used to create the channel for the corneal ring segment. You will be asked to look towards the centre of a ring of lights. A suction ring will be placed on your eye, giving a sensation of pressure and the vision will dim a little. The laser is then turned on, creating a 1mm wide channel in the cornea. To insert the Kerarings a speculum or spring is used to gently hold the eyelids open. The ring segments are then be inserted into the corneal tunnels created by the laser. A range of implant sizes are available for different degrees of correction. In most cases the incision will be self-sealed and sutures will not be required. A bandage contact lens is usually placed on the eye to improve the post-operative comfort. This is removed after a week. Following the procedure, you will be taken into a recovery room where you will be able to rest and relax for a short while before going home.

Activity limitations

The visual recovery after intracorneal ring segment treatment is usually relatively quick. You may find that you can go to work after 2-3 days.

Am I suitable?

Patients with severe keratoconus or with extensive scars in the cornea are not good candidates for the Keraring procedure. Other treatment options would be offered in such cases.

  • Wear sunglasses for comfort and protection for at least 1 week when outdoors.
  • You may resume driving once you can read a number plate at 70 feet. If you are in doubt, Mr Wilkins will check that your vision is at the driving standard. Driving with good vision in only one eye is legal, but you should obviously exercise caution until you feel confident, and drive short distances by day in familiar surroundings. It is important to contact Mr Wilkins if you experience progressively severe pain, increasing (rather than decreasing) redness of the eye or progressive worsening (rather than improvement) of vision after the surgery.
  • Do not use eye make-up for one week after surgery.
  • Try not to get water or shampoo in your eyes in the shower or when washing your face (dab very gently with towel if you do) during the first week. For the first 2-4 weeks, you should not swim in chlorinated water, play rugby or practice any type of martial arts or contact sports (boxing, kick-boxing) where there may be a direct blow to the eye. Chlorinated pools can irritate the eyes and public pools are commonly contaminated. Wear goggles when swimming.
  • Running, aerobics or working out in the gym are fine from a week after the surgery. Similarly, playing golf, tennis, badminton etc. are fine after a week.
  • Scuba diving can be resumed after a month.