Ortho-K – overnight vision correction
Ortho-K (orthokeratology), also known as overnight vision correction, is the use of specially designed RGP (rigid gas-permeable) contact lenses to alter the shape of the cornea during the night. Once the lens is removed in the morning, the changed corneal shape provides clear corrected vision throughout the day.
Ortho-K correction allows you to be free of both contact lenses and spectacles for the majority of, or possibly all, waking hours. The freedom from any artificial aid appeals to myopic glasses and contact lens wearers and is ideal for sportsmen, those who work in dusty or dirty environments or people who find spectacles and conventional lenses a nuisance.
It is a suitable and reversible option for those who are either unsuitable or are not keen on laser refractive surgery.
Ortho-K lenses are also offered to the group of patients suffering from dry eyes who are no longer able to wear contact lenses comfortably during the day.
We use EyeDream lenses from No7 Contact Lenses because they produce “accelerated orthokeratology for the reduction of myopia in low-mid myopic corrections, using the trusted EyeDream system”.
Ortho-K can also be effective with low degrees of astigmatism. The fitting process is aided by corneal topography that accurately scans the cornea and allows the manufacture of lenses with much greater accuracy than in the past, giving a controlled and precise reduction in the eye’s optical imperfection. In addition, new developments in lens materials have been made that enable safe overnight wear to be possible.
Ortho-K can help control myopia progression
Ortho-K can be used to help control myopia progression in children and teenagers by changing how the peripheral vision is focussed, which has been shown by recent studies to be the driving force behind myopia progression. Glasses and regular contact lenses will control central blur, providing a clearly perceived image, however light is focussed behind the retina in the periphery. Due to the unique way in which Ortho-K contact lenses change the corneal profile to correct the myopia, peripheral retinal blur is brought forwards so that light is focussed in front of the retina. This effect is believed to be the reason why Ortho-K is effective to help control the myopic shift in youngsters. Please visit our myopia control page for more information.
We are all individuals and we all have different visual needs. At Burnett Hodd & Tam we are always prepared to give you the time that you need and work hard to find the solution that is the best for you.
Who is suitable for Ortho-K?
The procedure works best for prescriptions of up to -4.00 dioptres of myopia and 2.00 dioptres of astigmatism. Errors above this may be reduced but total correction is not usually possible. In addition, there are several unknown factors for each individual, such as the complexity of the corneal shape and the rigidity of the cornea itself, so the speed of corneal moulding from one individual to the next will vary. While the success rate is very high, total success cannot be guaranteed due to these factors.
What does the procedure involve?
First, an assessment appointment including a full eye examination and computerised corneal topographical scan will be required. This will give us the opportunity to assess the general condition and health of the eyes and also to determine the likely effectiveness of the procedure in you.
Based on these measurements, a pair of Ortho-K contact lenses will be manufactured to reshape the cornea to a flatter profile to reduce myopia and astigmatism while dramatically improving unaided eyesight. Excellent vision and comfort are normally maintained while wearing Ortho-K contact lenses.
You will have an assessment the first morning after wearing the lenses overnight, and then the lenses will take around two weeks to have their full effect. The next check up will be after two to three weeks, when we will check that the full correction has been attained. If not, the lenses will be remade, usually with minor adjustments, until the vision is sufficiently corrected (although you will only pay for the final, successful pair of lenses). You can expect to need around two to four visits in the first two months of being fitted with Ortho-K contact lenses.
Once the lenses are working well and the vision is sufficiently corrected, you will need to wear the lenses every night in order to maintain the effect. A check-up every six months is recommended and you will need to replace the lenses every six months to a year, as they will degrade with time and usage.
The benefits of Ortho-K
The advantages over laser surgery (Lasik)
No ethical surgeon will treat a patient until they are at least 18 or, more usually, 21 years old. Ortho-K is available to children of a young age and upwards.
There is significant understanding of the effects of contact lens wear on the cornea because of the many years of lens use. There is no post-operative pain. Ortho-K is significantly cheaper and does not preclude surgery in the future. As yet, the long-term effects of Lasik are not totally understood.
Things to be aware of
What are the costs?
The procedure is time consuming and involves several lens changes, which means that there will be more than one consultation fee. Once complete, the ongoing costs are significantly less than conventional soft contact lens wear. In the first year you can expect to pay around £1,000, which covers all of the appointments, and one pair of lenses. This cost will be slightly higher if you have astigmatism, as the lenses required are more complex.
