Orthokeratology refers to a small and hard contact lens that is placed on the eye at the end of the day, slept in, then removed in the morning.
It is uniquely designed for each individual, adjusting for the different contours of one’s eye and allowing for correction of myopia or nearsightedness overnight.
This allows the individual to have improved visual acuity during the day and, in many cases, to walk around without the need of glasses to see clearly.
If the lens is used for myopia control, the lens is designed to ensure that there is clear vision centrally and slight peripheral blur for the child. This will ideally be minimally noticeable.
The lens functions by flattening the front of the eye temporarily, thus decreasing the overall power of the eye and allowing the patient to be free of glasses for one to two days.
The lenses are more rigid in comparison to regular soft contact lenses that are often prescribed for daily or monthly use. This lens will be used for one to two years and stored in a case.
As it is a hard lens made with a different material, the complication rate is lower than with regular contact lenses.
Who is a Candidate for Orthokeratology?
Depending on the underlying reason or motivation for orthokeratology lenses, the criteria will vary. For individuals hoping to use the lens to allow for freedom from glasses, the candidate must be a myope, meaning that they have a minus prescription.
They should not have a history of disease at the front of the eye and should have a history of good compliance with contact lens hygiene if they have worn them in the past.
Clinically, our optometrist will determine other factors such as the curvature of the eye and amount of astigmatism at the front of the eye. Athletes or those needing vision correction to see underwater are often great candidates for this specialty lens.
Myopia control is another common reason for using this lens. It is important to note that progression of myopia occurs throughout a child’s adolescent years and often slows or stops when they stop growing (late teens or early twenties).
The same aspects listed above are also relevant for children seeking to reap the benefits of myopia control from the ortho-K lens.
Depending on the child, there is no minimum age, as long as they are motivated to comply with nightly lens insertion, with or without parental guidance.
How Do We Fit Ortho-K Lenses for Myopia Control?
The fitting appointment consists of getting measurements as well as getting a starting point for the visual acuity and refractive error.
Best vision possible with glasses will be recorded as well as the glasses prescription. This is especially important for children undergoing myopia control.
A detailed scan of the front of the eye will be taken to determine the curvature, thus allowing for a more personalized fit. In addition, a slit lamp examination will allow our optometrist to ensure there is no pathology at the front of the eye and no contraindicatory factors.
In cases of myopia control, an A-scan may also be done in order to determine the length of the eye and assess for progression of growth.
A diagnostic lens may be fit on the eye in the initial fitting and assessed. Adjustment will be made and a new lens will be ordered by our eye doctor.
Follow up exams will be required to ensure an adequate fit before finally dispensing the lens to the patient.