Ortho-k is a non surgical process that reshapes (flattens) the cornea using contact lenses to reduce nearsightedness and astigmatism. Ortho-k was first used over 40 years ago when hard lenses were the only materials available. A series of hard lenses were needed during daytime wear until the desired results were attained.
This often times took many months to accomplish. Accelerated ortho-keratology was started in the late 1990’s because of the availability of new rigid gas permeable materials that were approved for overnight use along with advances in computer assisted lathes and technological advances in the procedure. It is now possible to achieve reduction of a common vision disorder called myopia in a matter of days.
Since the amount of corneal flattening can be precisely controlled, it is possible to bring the eye into correct focus and correct for the refractive error. After removing the lenses the cornea maintains its flattened shape for most or all of the day. A retainer lens is then used each night to maintain the corneal flattening, otherwise the myopia will begin to revert back to its pretreatment level.
How Does Ortho-k Work ?
After being fit, the ortho-k lenses will flatten the cornea by shifting the outer layer of the cornea (the epithelium) more peripherally. Since the cornea is flattened and retains the flattened curvature for a period of time it is sometimes referred to as "corneal molding". This molding is accomplished by a specially designed lens that is somewhat larger than a standard lens but not much different in appearance.
Patients usually find comfort to be initially very good and excellent after about 3 days of wear. The lens actually works as it is worn and good functional vision occurs in a few hours to a week or two depending on the initial prescription that is being corrected. The stronger the initial prescription, the longer it will take to correct. The cornea can be easily fine tuned by slight modifications to the retainer mold.
Ortho-k uses corneal topography to accurately determine the corneal shape before treatment. The topographer "maps" the surface of the eye which enables the doctor to precisely design the lens parameters. The corneal mapping by the topographer is then used to determine if the retainer lenses are correctly changing the corneal shape which will ultimately result in clear vision.
Who Is Eligible For Ortho-K ?
Both children and adults can be treated with ortho-k since the principles of flattening the cornea is not effected by the person’s age. The most important reason for treating children is to stop or decrease the progression of myopia. Ortho-k is used to slow or stop the increase in axial length of the eye that occurs in growing children who are becoming more nearsighted on a yearly basis.
This stabilizing effect has advantages long term where a patient may be able to function when not wearing glasses or contacts and possibly being able to preserve the possibility of having refractive surgery when getting older where many patients are no longer candidates because they have become too nearsighted and are no longer eligible to have the surgery.
The second advantage for children is the ability to participate in sports without having to wear corrective eye wear. Glasses can be cumbersome when playing sports and contact lens wear is inconvenient when being around dusty environments or when swimming. There is always the risk of being hit or poked in the eye when playing sports and having the lens "pop out" and being lost.
Ortho-k For Adults
The main reason why adults will have this procedure done is because of dry eyes and the inability to wear lenses comfortably during the day. Complaints with dry eyes vary from decreased wearing time to lenses getting cloudy and uncomfortable by days end.
Wearing lenses at night and being "contact lens free" during the day has changed many of our patient’s lives. Some adults prefer ortho-k to refractive surgery because the treatment is totally reversible. The lenses do a great job of correcting vision although discontinuing wear will always result in the patients vision going back to pre-treatment levels but no worse.