Orthokeratology (Ortho-K) is a non-surgical night time vision correction by the use of contact lens to reshape the cornea. Ortho-K can provide you a spectacle free vision during the day time. It can be an alternate way to daytime contact lens and Lasik surgery. Orthokeratology (Ortho-K) is also a method for myopia control and dry eye management. By the use of a series of highly oxygen transmissible rigid contact lenses, the cornea will be moulded and flatten during the night under supervision of optometrist. Orthokeratology is effective in reducing moderate myopia and astigmatism during the day time. In addition, scientific research demonstrated that orthokeratology may effectively stop or retard the myopia progression. It is also used for handling dry-eye people for contact lens purpose.
Aim of Orthokeratology
- Myopia control
- Contact lens option for dry eye
In modern accelerated orthokeratology, the cornea is reshaped by a specially built highly oxygen permeable contact lens in an eye close condition. Orthokeratology needs high accuracy of corneal profile assessment so that the night time contact lens could fit with the eye. It is guided and monitored by state of art corneal topographer (an equipment that scans shape and profile of the eye). With a topographer, the corneal shape modification and accuracy can be reviewed immediately.
Who are suitable for Orthokeratology lenses?
- At least 6 years old
- Less than -9.00D of myopia and less than -3.00D of astigmatism
- For those with myopia that are progressing rapidly
- For those who plays sports and water sports frequently, e.g. swimming, diving and skiing
- For those who is not suitable for LASIK refractive surgery
- For those with dry eye problem
Pros and Cons of wearing Ortho-K lenses
- A better vision can usually be maintained throughout the day after removal of Ortho-K lenses.
- Recent research has shown the usage of Ortho-K lenses is effective in slowing myopic progression in children.
- Complication associated with conventional contact lens wear, such as dry eyes and irritation from dust can be avoided.
- A safe alternative to LASIK laser refractive surgery with no wounds and no dry eyes.
- The ortho-K lenses effect is reversible and can be stopped anytime. The eyes will soon resume their original myopic power.
- Ortho-K lenses is NOT a CURE for myopia. The Ortho-K control myopic power effect will wear off gradually after cease of lens wear.
- Aftercare consultations are necessary to ensure effectiveness and safety.
- Some contact lens related problem, such as solution sensitivity, infection, corneal epithelial trauma or ulceration may occur, though the risk of complication is very dependent on compliance.
In 2011, researchers from Japan presented a study that evaluated the effect of ortho-k lenses on eyeball elongation in children, which is a factor associated with myopia progression.
A total of 92 short-sighted children completed the two-year study: 42 wore overnight ortho-k lenses and 50 wore conventional eyeglasses during the day. The average age of children participating in the research was about 12 years at the beginning of the study, and children in both groups had essentially the same amount of pre-existing myopia (-2.57 D) and the same axial (front-to-back) eyeball length (24.7 mm).
At the end of the study, children in the eyeglasses group had a significantly greater increase in the mean axial length of their eyes than children who wore the ortho-k contact lenses. The study authors concluded that overnight orthokeratology suppressed elongation of the eyes of children in this study, suggesting ortho-k might slow the progression of myopia, compared with wearing eyeglasses.