What Is Corneal Refractive Therapy?
Corneal refractive therapy (CRT) corrects myopia (nearsightedness) by sleeping in special contact lenses overnight. They are worn before bedtime and removed when waking up in the morning, and improve daytime vision in nearsighted people. They work by changing the curvature of the cornea, the front of the eye, while asleep. The lenses are a good option for children and adults who have an active lifestyle or want to be lens-free during the day.
CRT lenses may also control the progression of nearsightedness in children. A child with rapidly increasing nearsightedness can use CRT lenses to slow down the progression of nearsightedness. High myopia (nearsightedness of -6.00 DS or greater) can lead to problems such as retinal detachment and glaucoma in adulthood. CRT lenses may minimize the risks of a child developing high myopia.
Key Takeaways
- Corneal refractive therapy (CRT) lenses are hard contact lenses that reshape the eyes while sleeping, allowing one to see clearly without glasses or contact lenses during the daytime.
- The effect of CRT lenses is temporary, so the lenses must be worn every night to maintain sharp vision.
- CRT lenses are typically used for people who play sports, or to manage the progression of myopia (nearsightedness) in children.
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Understanding Corneal Refractive Therapy
Corneal refractive therapy (CRT) is the process of using special hard contact lenses that are designed to reshape the eye overnight. CRT is also known as OrthoKeratology (Ortho-K). CRT uses gas-permeable contact lenses that are worn overnight and removed in the morning. The material of the CRT lenses is highly oxygen permeable and thus approved for overnight wear. CRT lenses correct the nearsighted prescription overnight. They work by gently and gradually reshaping the cornea, the front surface of the eye. People who wear CRT lenses overnight have clear vision during the day without glasses or contact lenses.
CRT lenses or Ortho-K lenses only temporarily correct the vision. Their effect lasts for 24 to 72 hours after the lenses are removed. It takes around two weeks after starting CRT lenses to fully correct the prescription. The contact lenses can correct moderate nearsightedness (myopia) up to -6.00 diopters and astigmatism up to -1.75 diopters.
Why Choose Corneal Refractive Therapy?
The basic goal of corneal refractive therapy (CRT) is to avoid using contact lenses or glasses when awake. People who typically benefit from CRT include:
- Children and adults who do sports, such as swimming, or have active lifestyles
- People working in dusty or dirty environments
- Children with rapidly increasing nearsightedness (myopia)
- Children whose parents have high nearsighted prescriptions
- Anyone who prefers to be contact lens-free or glasses-free during the daytime
Downsides of Corneal Refractive Therapy
The downsides of corneal refractive therapy (CRT) include:
- Initial discomfort or eye pain when trying rigid gas-permeable lenses
- Experiencing blurry vision for the first two weeks of CRT wear
- Slightly higher rate of eye infections compared to daytime soft contact lenses
- Slower rate of natural healing of the eyes after extended overnight wear
Corneal Refractive Therapy Procedure
- The eye doctor will fit a contact lens onto your eye and ensure that it fits the unique shape of your eyes. Some lens parameters may need to be adjusted, so they might need to try a few different options.
- After finding a close match, the eye doctor will instruct you on how to insert and remove the contact lenses. Since most people have not used hard gas permeable lenses before, they usually experience moderate discomfort when the lenses are first tried. The eye should gradually get used to the hard lens material over the course of two weeks.
- Once you are able to safely and comfortably insert and remove the contact lenses, you will be allowed to take them home.
- You should put the lenses onto your eyes approximately ten minutes before you sleep.
- You will remove the lenses as soon as you wake up in the morning.
- People usually experience great eyesight within a few days. Most people will reach their ideal vision within 10-14 days.
- The eye doctor will schedule regular follow-up appointments, typically every 3 months, to make sure the contact lenses are still fitting well.
