FREQUENTLY ASKED QUESTIONS (FAQS)
• The most often asked questions about orthokeratology by patients to
• Questions that are frequently asked about orthokeratology from fitters
to the laboratory.
The FAQ (Frequently Asked Questions) section may be applicable to fitter,
manufacturer, or consumer, depending on their knowledge of
Q: How do ortho-k lenses work?
A: Ortho-k shaping lenses are designed to progressively reshape the central surface of
the cornea systematically, similar to the effect of lasers in reversing nearsightedness.
However, unlike laser surgery, the effect of ortho-k treatment is temporary and
Q: Is everyone a candidate for ortho-k?
A: No! While orthokeratology can help most individuals (including those with certain
types and amounts of astigmatism and moderately high myopia) improve their vision, the
procedure is often most effective for those prescriptions falling within a specific range.
Additional factors may include individual corneal rigidity and shape factors as well as an
ability to wear contact lenses. A thorough consultation and examination using advanced
computerized diagnostic instrumentation can easily determine if orthokeratology is right
for an individual.
Guide to Overnight ORTHOKERATOLOGY
Q: Who is not a candidate for ortho-k?
A: While ortho-k can be performed on practically anyone with healthy eyes who can
insert a contact lens and follow lens care directions, it is not recommended for people
with prescriptions above 5.00 diopters of myopia or above 1.50 diopters of astigmatism.
Also, people with pupils that are larger than normal (> 6 mm in normal light) and those
having irregular corneal astigmatism or any corneal disorder such as keratoconus are
Q: How safe is ortho-k?
A: Ortho-k is believed to be safe when appropriately fitted and managed properly. Many
people have been able to eliminate their dependence upon their glasses and standard
contacts with no adverse effects. Unlike surgical procedures like radial keratotomy (RK),
photorefractive keratectomy (PRK), laser assisted in-situ keratomileusis (LASIK), and
laser assisted subepithelial keratectomy (LASEK), the corneal tissue is not incised or
vaporized by a laser. As with all contact lenses, proper lens care and handling must be
performed to maintain eye health. The state-of-the-art, high-permeability GP materials
now available provide adequate amounts of oxygen to the tissues of the eye.
Q: Is ortho-k permanent?
A: After treatment, maximum results are achieved and retainer shaping lenses are worn
to stabilize and maintain the new corneal shape. Failure to wear the shaping lens on an
ongoing basis will result in a return to the pre-existing prescription. Retainer shaping
lenses will likely be prescribed for overnight wear.
Q: What are the risks of wearing lenses overnight?
A: The complications of wearing contact lenses include corneal ingrowth of vessels,
ulcers, and abrasions.The risks associated with wearing contact lenses overnight are
higher than wearing contact lenses only while awake. Contact lenses cannot become lost
behind the eye (this is anatomically impossible) and it is rare for ortho-k shaping lenses
to become decentered from the cornea.
Q: How long does it take for the process to stabilize and provide functional vision for the
A: It generally requires four to seven consecutive nights of wearing the shaping lenses
to achieve the desired result. It may take somewhat longer for those with higher degrees
Frequently Asked Questions
Q: Are ortho-k lenses uncomfortable to wear?
A: Overnight wearing of the shaping lenses is surprisingly comfortable. Most patients
are unaware of their presence within a very short time after insertion. And because the
ortho-k shapers are made in large diameters and worn during sleep, the normal
adaptation process is very short.
Q: Will I still have to wear glasses or contacts?
A: Once the desired myopic reduction is obtained, the final shaping lenses act as
retainers to maintain that level. Regular contact lenses are not needed. Glasses may be
needed for reading or other part-time use. During the initial treatment period, if unaided
vision does not last a full day, the patient will be given soft disposable contact lenses to
wear to maintain normal distance vision.
Q: Once the treatment phase is completed, how frequently will I need to wear the
overnight retainer lenses?
A: Most people will need to wear the shaping lenses six to seven consecutive nights in
order to enjoy good, unaided vision during the entire day. Patients with lesser degrees of
myopia (nearsightedness) may find that wearing them every other night is satisfactory.
However, this will be determined on an individual basis by the eye care practitioner.
Q: How much myopia can a person realistically expect to be able to reduce using
A: Generally, 5.00 diopters of myopia is the upper limit for myopia reduction. However,
work is underway on designs that will hopefully correct higher amounts of myopia.
Lower amounts of myopia are easier and faster to reduce.
Q: How about ortho-k for astigmatism?
A: The amount of astigmatism reduction achievable will depend on the amount and the
type. 1.50 diopters of “with-the-rule” corneal astigmatism and 0.75 diopter of “againstthe-
rule” corneal astigmatism are considered the upper limits for astigmatism
reduction. Ortho-k will not have an effect on residual (internal) astigmatism.
Q: How long does it take to be able to see well without glasses?
A: Rapid visual improvement normally occurs in the first few days. Stabilization then
follows over the next few weeks and months. Once the wearer’s eyes are stabilized,
improved eyesight is maintained by wearing shaping lenses as recommended to maintain
vision at the desired level.
A Guide to Overnight ORTHOKERATOLOGY
Q: If the patient decides to return to wearing glasses, can vision be restored to its
A: The wearer’s eyes will return to their pre-treatment nearsightedness after about two
weeks. Depending on how long ortho-k lenses have been worn, this process may be as
long as 30–90 days. In order to provide good vision during this transitional period,
patients are refitted with gas permeable lenses or disposable soft lenses while the
corneas recover their pre-treatment shape.
Q: If the patient becomes less nearsighted or presbyopic in later years how will that be
A: Unlike laser surgery that cannot be reversed, corneas can usually be remodeled to
accommodate the change in prescription by changing the design of the maintenance
lenses to correct for near vision using a technique called “monovision.”
Q: How much does ortho-k cost?
A: The actual cost will depend on the complexity of the case. Each doctor sets fees
accordingly. Fees can range from $750 to $2,000 depending on length of treatment and
the number of shaping lenses needed. The doctor will be able to provide an estimate for
For the Fitter/Lab:
Q: What is the current prediction for the number of orthokeratology fits that will be
A: The use of orthokeratology will vary from market to market. Current estimates in the
US market suggest that there could be as many as 50,000 to 100,000 ortho-k fits
annually. Much of this will depend on the acceptance of the professional community,
potential candidates, and promotion from GP lens manufacturers and the media.
Q: Is it necessary to use topography to fit today’s ortho-k lenses or can I use
keratometry as I always have to fit GP lenses?
A: Use of topography is highly recommended in all phases of the fitting and
follow-up. Some fitting systems base initial shaping lens selection on topography data,
while others recommend use of manual keratometry. Virtually all ortho-k fitting systems
recommend the use of topographical data to establish a baseline reference as part of the
fit evaluation, to identify and help solve fitting problems and to monitor the progress of
Frequently Asked Questions
Q: What are the benefits of using four and five zone designs over the earlier three zone
A: These modern four and five zone shaping lens designs use wider alignment (midperipheral)
zones to achieve easier, more stable lens centration. Corneal shape changes
can be made in larger increments; myopia reduction occurs more rapidly, requiring only
one pair of shaping lenses in a high percentage of cases. This makes material costs to
both fitter and patient lower.
Q: If ortho-k shaping lenses need modification or blending, can I do this in my office to
A: While in-office lens modification has long been a skill valued by lens fitters, modern
ortho-k shaping lens designs are complex and precise. Any hand modification made by
the fitter to improve the lens fit will probably be impossible to duplicate if a lens is lost,
broken, or requires other parameter changes.
Q: How important is dispensing and the next-day visit in evaluating the overnight ortho-k
shaping lens fit?
A: Each patient will respond differently to orthokeratology treatment. These shaping
lenses generally tighten with wear, which may occur in as little as an hour. It is
important to evaluate the shaping lens after allowing it to settle-down in the office.
Centration is the key to a successful ortho-k treatment; therefore, shaping lenses must
be checked early the first morning for centration, binding, and adhesion. Shaping lenses
are then removed to evaluate topography and to check unaided visual acuity.
Q: If an ortho-k shaping lens is lost, broken, or not able to be worn, how can I provide
suitable vision to the patient until the replacement lens arrives?
A: Soft disposable lenses can be prescribed until the proper replacement shaping lens
is received. If the cornea begins to revert back to higher myopia, stronger disposable
lenses can be given. The wearer should be checked once again the day after a new
shaping lens is worn overnight.
KEY POINT SUMMARY…
• The success of orthokeratology in the practice and in the laboratory is
dependent on being able to address and adequately answer any
questions that arise before, during, or after orthokeratology treatment.
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Second Edition, 2004