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Orthokeratology or Corneal Refractive Therapy (CRT) is an innovative treatment that allows sufferers of mild or moderate myopia to be free from contacts and glasses throughout the day without the cost and risk of laser eye surgery.

The principle behind the treatment has existed for centuries, originating from a Chinese practice of sleeping with teabags on the eyes to correct short-sightedness.
Through the use of revolutionary lenses that utilise recently developed materials and technology, your vision is gently corrected while you sleep. It works in much the same way that dental braces do, but unlike braces the change is not permanent. If you stop wearing the lenses your vision will return to its uncorrected state. Ortho-K has benefits for any short-sighted person who wishes to be free from lenses or glasses, but can have particular benefits for those who participate in contact or water sports, people who work in dusty environments, and for young children who are just becoming short-sighted. Some research has indicated that Ortho-K may prevent further myopic progression.

Why Have Ortho-K?

Orthokeratology allows you to achieve normal vision without needing to wear contact lenses or glasses throughout the day, or requiring laser eye surgery. Lens and surgery free vision appeals to the majority of people who suffer from myopia, but it is especially beneficial for those who find contact lenses or glasses a hindrance.

CRT lenses are beneficial to people who work in dusty or dry environments, and experience irritation with normal contact lenses. Orthokeratology is also suitable for sufferers of dry eyes and for those who find wearing contact lenses in normal conditions to be uncomfortable. The overnight use of the lenses eliminates irritation and lens awareness due to blinking and eye movement, problems that are rarely experienced when the eyes are closed and during sleep. This also eliminates evaporation of liquids from eyes, the main symptom of dry eyes.
Orthokeratology is especially beneficial for active teens who find that contacts or glasses get in the way of social or sporting activities, but are unsuitable for laser-eye surgery due to age or preferences. It may also have a benefit in avoiding further progression of myopia in adolescents and children.

Who is suitable for Ortho-K?

Ortokeratology is most effective for sufferers of mild to moderate myopia (up to -6.00D) with or without astigmatism (up to -1.75D). There are no age restrictions on the use of CRT lenses, and they have been used with children as young as 12. Studies have even shown that the use of CRT with adolescents and teens in the early stages of myopia may restrict, or even halt its progression.

Orthokeratology is not an effective treatment for presbyopia (age-related sight-impairment), but sufferers may still be treated through the use of CRT, with one eye corrected for distance, and one for reading, though reading glasses may still be required.

How does Ortho-K Work?

In a myopic eye the cornea, which focuses light onto the retina, is too steep and images are focused in front of the retina instead, making far away objects appear blurry. Through the use of specially designed rigid lenses, made from a highly gas-permeable material which allows oxygen to reach the eye, pressure is gently exerted on the centre of the cornea, flattening and thinning its surface and resulting in images being more accurately focused onto the eye.

What does the procedure entail?

Prior to fitting patients with CRT lenses, we will perform a thorough eye exam to assess the health and condition of your eyes.  We then measure the precise shape of the surface of your eyes using a Computerised Corneal Topographic Scan. The scan takes a few seconds and is completely painless. This results in a topographical map of your eye, allowing us to accurately assess if CRT is appropriate for you, and if so, what lenses are required. For most patients lenses can then be fitted immediately, though in some cases we will need to order them in.

Once CRT lenses have been fitted we will schedule an appointment for the following day, where we will perform another eye exam and topographic scan to ensure that the lenses are working as expected. Most visual change will occur in the first two to three weeks, and will require frequent appointments to monitor changes in the corneal shape.

A majority of patients experience a significant change in the first few days, though in some cases it can take between two to three weeks for desired vision to be fully achieved. Once you begin CRT your old glasses or contacts will no longer work effectively. Normal vision can be maintained throughout this period through either the daytime use of CRT lenses, or through a series of soft contact lenses. We will discuss the solution that is right for you in our consultations.

Once daytime vision has been stabilised you will only need to wear the lenses at night or for part of the day, with some patients only using the lenses one out of every two or three nights. If you wish to discontinue the treatment, merely refrain from using the lenses and your vision will return to its previous state after 72 hours.
What are the advantages of Orthokeratology?

  • Freedom from glasses and contact lenses throughout most or all waking hours.
  • Discomfort normally associated with contact lenses, hard or soft, is minimised or eliminated through overnight use.
  • A very safe procedure, with risks comparable to those associated with normal contact lens wear.
  • Allows active teens and children to engage in a variety of activities and sports free from the discomfort and inconvenience of glasses and contact lenses.
  • Can halt the further progression of myopia in children.
  • They are only worn at night greatly reducing the risk of lenses being lost or damaged.

What advantages does CRT have over Laser Eye Surgery?

  • It is a non surgical procedure that does not permanently alter the cornea.
  • The effects of Ortho K on the cornea are well understood, with contact lenses being used for more than fifty years.
  • In contrast to laser eye surgery, CRT is available for adolescents and teens.
  • CRT treats both eyes at the same time.
  •  Patients don’t experience any post-operative pain.
  • The procedure does not leave you with hazy vision.
  • Treatment can be adapted to ongoing changes in prescription as myopia .progresses.
  • It is reversible, with vision returning to normal after 72 hours after discontinuing treatment.


What are the disadvantages?

  • The treatment requires several consultations in the first few months.
  • The treatment requires the continued use of retainer lenses in order to maintain good vision.
  • While success rates are high, full vision correction cannot be guaranteed.
  • The rate of visual improvement can vary from one patient to the next.
  • Instructions must be followed thoroughly to achieve best results.

How much does the procedure cost?

An initial appointment fee of £50, for a full assessment of suitability and a quotation for a full fitting, will be given.
Ongoing charges for Corneal Refractive Therapy are equivalent to wearing superior daily soft lenses.


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