Myopia management is one of the fastest-growing specialty areas in optometry today. Although we have a number of management strategies available to us in clinical practice, orthokeratology—more commonly referred to simply as Ortho-K—often elicits the most excitement from parents and patients alike.
The freedom from daytime visual correction coupled with effective myopia control is a unique attribute of Ortho-K. This non-surgical process is used to correct vision by reshaping the cornea with specially designed contact lenses that are worn overnight.
In the following article, we’ll provide you with the information and tools necessary to effectively implement Ortho-K in your practice, including everything from:
- Patient selection criteria
- Study data on clinical efficacy
- Discussion points when speaking to potential candidates and their parents
- Tips on lens selection
- Marketing strategies
- Establishing an appropriate fee structure.
Let’s begin by focusing on candidate selection: What makes someone a good candidate for Ortho-K?
Candidate selection for orthokeratology lenses
Identifying suitable candidates for Ortho-K involves consideration of several important criteria.
Age
Age plays a critical role in the selection of good Ortho-K candidates. Generally, this management strategy is suitable for a broad age range, including children, teenagers, and even adults. Children, particularly those aged 6 to 12, are most often the ideal candidates for Ortho-K, based upon its ability to slow the progression of myopia, which otherwise tends to advance rapidly during these years.
Additionally, the unique overnight wearing schedule allows parents to be involved in the daily routines of lens application, removal, and care, maximizing the safety and compliance of the treatment.
In addition to the prevalent use of Ortho-K for myopia control, adults with mild to moderate myopia can also benefit from this modality. The induced higher-order aberrations, and hence the extended depth of focus provided by this treatment, makes it an effective modality for presbyopic correction.1,2
Refractive error
The degree of refractive error is another important criterion to be considered. Ortho-K is most effective for individuals with low to moderate myopia—typically up to -6.00 diopters—with minimal to moderate astigmatism.
Despite some documented successes involving Ortho-K in patients with high myopia, the visual outcome, risk of complications, and chair time throughout the fitting process are, in general, much more favorable in cases of low to moderate myopia.
Motivation / Parental support
The success of Ortho-K depends greatly on the motivation and compliance of the patient. For younger individuals, parental support and involvement are crucial. Parents need to ensure that their child follows the prescribed lens-wearing schedule and maintains proper hygiene practices.
In instances where the child is unable to clearly verbalize minor issues related to the treatment, parents need to be more diligent in observing the child’s ocular health, such as redness, discharge, or tearing, especially right after lens application and removal. Considering the long-term nature of the treatment, motivation and a commitment to follow-up visits are essential for achieving optimal results and minimizing potential risks.
Contraindications and limitations
While Ortho-K offers significant benefits, there are several contraindications and limitations that must be considered.
Contraindications for Ortho-K include:
- Severe dry eye syndrome or ocular surface abnormalities
- Active eye infections or inflammation
- Significant corneal abnormalities or scarring
Limitations associated with Ortho-K include the need for ongoing lens wear to maintain the corneal molding, as well as the potential for discomfort or lens intolerance. Understanding these factors can help tremendously in selecting the most suitable candidates for this treatment modality.
The role of Ortho-K in myopia management
The mechanism of action of orthokeratology
Despite convincing evidence supporting Ortho-K’s efficacy in inhibiting axial elongation, the precise mechanism behind its myopia-controlling effect remains unclear. One widely accepted hypothesis suggests that the induced paracentral corneal steepening, a characteristic effect of the reverse curve (return zone) of the lenses, imposes myopic defocus in the peripheral field.
During myopia development and progression, the ocular structure grows asymmetrically, with the axial length increasing faster than the equatorial dimension, resulting in a prolate eye shape. As a result, myopic eyes experience relative hyperopia in the periphery when central vision is fully corrected.
Since persistent hyperopic defocus has been well established as a “myopia-go” signal in various animal models, it is plausible that myopia control can be achieved by reducing peripheral hyperopia.3 However, a clear dose-dependent response between the reduction of peripheral hyperopia and the efficacy toward inhibiting axial elongation has not been established in clinical studies.
In addition to its impact on peripheral myopia, Ortho-K treatment also induces significant higher-order aberrations (HOA), such as positive spherical aberration (SA+) and coma, due to the non-uniform flattening of the central cornea. Early clinical studies have reported a reduction in accommodative lag, a factor significantly associated with myopia, through the increase of HOA.4
It is worth noting that the changes in peripheral myopia and HOA induced by Ortho-K are inherently coupled, making it nearly impossible to isolate the exact contribution of each factor to the anti-myopia effect of Ortho-K.
Lastly, compared to other modalities, Ortho-K treatment offers clear, uncorrected daytime vision, which provides the best potential for behavioral improvements such as increased outdoor activities, which is itself a significant protective factor against myopia development.
In summary:
The mechanism of the myopia-controlling effect of Ortho-K is likely multifactorial. Efforts for individual customization of lens design to optimize long-term efficacy need to consider factors such as age of onset, baseline level of myopia, pupil size and angle kappa, and corneal biomechanical properties to better predict topographical changes and subsequent optical impacts on the retina.
Studies on the efficacy and safety of orthokeratology
Long-term efficacy of orthokeratology
Numerous studies support the long-term efficacy of Ortho-K in managing myopia.5 Research indicates that Ortho-K can slow the progression of myopia by 30 to 60% compared to single-vision eyeglasses or contact lenses. However, there is significant variability in the reported efficacy both between and within studies.
Factors impacting Ortho-K efficacy may include:6
- Age of myopia onset
- Level of myopia at baseline
- Ethnicity
- Lens design
- Pupil size
- Lens decentration
- Jessen factor
- Also known as the compression factor, this value represents the extra power added to the target of Ortho-K lenses to counteract daytime regression, represented by the base curve of the lens that is flatter than the patient’s keratometry readings
Compared to soft lens modalities, Ortho-K lacks treatment specificity. More specifically, the same lens design applied to different patients can induce dramatically different topographical changes, resulting in varying “anti-myopia dosages.”
Additionally, the effect of corneal molding is highly dependent on the proper selection of lens parameters, even within the same design principle, to allow the most efficient distribution of the hydraulic pressure induced by the lenses. Consequently, the achieved topographical changes, rather than the lens design itself, are likely better predictors of the controlling efficacy.
Safety of Ortho-K Lens Wear
Given the drastic increase in the prevalence of myopia worldwide and its notably earlier onset, the popularity of Ortho-K has grown significantly. Safety is of paramount concern in any contact lens modality, but Ortho-K certainly warrants additional scrutiny, due to its overnight wearing schedule, its corneal molding effect, and its target population in younger children.
Potential complications associated with Ortho-K include microbial keratitis (MK), corneal staining, and lens binding. Additionally, there are other clinically insignificant side effects, such as epithelial pigment deposits, increased visibility of fibrillary lines, and transient changes in corneal biomechanical properties.5
Multiple systematic reviews have investigated the long-term safety of Ortho-K lens wear in the pediatric population, and consistently reported that Ortho-K is generally a safe and effective option for myopia correction and axial inhibition.5,7
Microbial keratitis
Owing to potentially serious consequences, MK remains the most concerning complication related to Ortho-K. At least three factors have been shown to increase the risks of MK in patients using Ortho-K lenses, including overnight modality, minimal apical clearance (central bearing of lens fitting), and the reverse geometry design, with extended/overnight lens wear representing the most significant risk factor.5
It is worth noting that although extended and overnight wear are typically grouped together as one wearing modality, their impact on bacterial colonization of the lens surface, the ocular surface’s defense against infection, and the risk of lens adherence are drastically different. The long break from lens wear during waking hours in an Ortho-K regimen allows for the restoration of team film composition, healing of corneal epithelial defects, and disinfecting of the lens surface.8
Although it has been reported that the incidence of MK tends to be slightly higher in children than in adults, the data need to be interpreted with caution.7 First of all, the total number of incident cases was small, resulting in a bigger variance in the risk estimate. Furthermore, most studies were subject to significant patient selection and participation bias because of the age difference of the patients.
Although the exact magnitude of effect due to bias was difficult to evaluate because of the retrospective nature of most studies, the direction of the overall effect estimate will be biased toward younger aged patients, assuming greater parental attention and a higher probability of seeking follow-up visits as compared to that of young adults.
It is worth noting that Pseudomonas aeruginosa and Acanthamoeba were the most commonly reported pathogens for Ortho-K-associated MK, both of which require early diagnosis and prompt treatment to minimize the risk of permanent vision loss. As a result, both patients and parents should remain highly vigilant to possible signs and symptoms of infection, and comply with all follow-up appointments to minimize the risk of irreversible vision loss that this threat poses.
In summary:
The safety profile of overnight Ortho-K is comparable to daytime soft contact lenses. The long-term success of this treatment relies on several key factors, including optimal lens fitting, strict adherence to lens use and care guidelines, regular follow-up appointments, and timely treatment of any complications.
Patient education and presenting Ortho-K to parents
While Ortho-K is currently a hot topic within optometry, it remains a relatively unknown entity to many patients and their parents. Thus, the conversation and education regarding this modality are likely to be initiated by you. We strongly recommend that practitioners describe Ortho-K in simple, basic terms, such as the following:
It’s crucial to convey that even though this may be the first discussion the parents have had about it with an eyecare professional, Ortho-K itself is not a new concept. In fact, there are designs that have been US Food and Drug Administration (FDA)-approved for many years and regarded as safe and effective treatments for myopia, with the first lens being approved over 20 years ago.7
On that same note, however, always be sure to acknowledge that Ortho-K is an off-label option for myopia control, but there are several studies backing it’s safety and efficacy.5,9,10 For most parents, this fact has very little bearing on their decision to choose Ortho-K for their child’s myopia management. Parents typically will yield to the doctor’s recommendation, trusting in your experience and expertise.
When there is opposition, it will likely stem from the parents doubting whether their child is old enough or mature enough to succeed in contact lenses. If the child demonstrates responsibility in other aspects of their lives, like brushing and flossing daily or regularly making their bed, this is a good indication that they may be ready to take on contact lens wear. Also, some children are mature enough, but the fear of contact lenses may be prohibitive.
In these cases, have the child start using artificial tears daily to get them used to the concept of something going into their eyes. Lastly, reassure the parents that they are not alone in this journey. You and your team are dedicated to helping their child succeed through consistent and supportive in-office training and guidance.
Another potential barrier is the cost associated with Ortho-K. There may well be initial “sticker shock” when discussing fees, but stress this is an investment in their child’s eye health and overall well-being. In addition, when broken down, the fee for Ortho-K is typically comparable to the cost of continuously updating glasses and contact lenses for a progressive myope over a period of several years.
Initial patient assessment for orthokeratology
Before proceeding with Ortho-K, a thorough examination of the patient is imperative. This should include a comprehensive case history, binocular vision and accommodative assessment, cycloplegic refraction, pupil assessment, and anterior and posterior segment evaluation. For a comprehensive look at the child’s myopia, measuring axial length through the use of a non-contact optical biometer is also helpful.
In addition, topography represents a crucial piece of clinical information for two reasons:
- It helps to further rule out any corneal irregularity, such as corneal dystrophies or degenerations.
- It provides all the necessary corneal data to achieve the best contact lens design.
Orthokeratology lens selection
There are several Ortho-K lenses readily available for use today. The most challenging decision is selecting the lab with which you want to work, as you will be working quite closely with them.
Below are several factors that should be considered when choosing an Ortho-K lens:
- Are the lenses designed through a diagnostic fitting, online calculator, or topography? What equipment is required to design these lenses?
- What is the turnaround time on lens manufacturing?
- How readily available is the consultation team?
If you’re still unsure of which lab to choose, a good place to start is with a specialty lab with whom you already have a good working relationship, because most will also offer an Ortho-K design. Once you have selected your lab, the ordering process is typically very straightforward.
The key pieces of clinical data needed before designing lenses are:
- Manifest refraction
- Topography measurements
- Horizontal visible iris diameter (HVID)
Application and removal of Ortho-K lenses
Application and removal of Ortho-K lenses can create significant apprehension in both patients and parents. Most often, the fear is rooted in the unknown and not necessarily associated with the actual lens itself. The key to success is to be patient and supportive with the family.
On the initial dispensing visit, be sure that you or your most educated and experienced technician is working with the patient. Most children need to be front-loaded before jumping right in. Let the child know the following:
With this type of explanation, the child’s nerves are often eased and the application process typically goes much smoother.
Fitting and follow-up for orthokeratology
During the dispensing visit, several key pieces of clinical data should be collected with the lenses on the eye.
Clinical data to consider when fitting patients for Ortho-K lenses:
- Visual Acuity: Acuity with the lens on should closely match the patient’s best corrected visual acuity from the initial visit.
- Refraction Over the Lens (ROL): In order to achieve the best visual results, the ROL should be +0.50 to +1.00 to ensure neither over- or under-correction.
- Lens Fit Assessment: The lens should be well-centered with an appropriate “bull’s eye” fluorescein pattern.
If all of the above requirements are met, the lenses can be dispensed and the patient scheduled for a follow-up the very next day. At the 1-day follow-up, have the patient wear the lenses into the office if possible; this will allow you to assess the fit after the first night’s wear. Repeat the same clinical tests as on the dispensing visit, in addition to unaided visual acuity, refraction, topography, and anterior segment assessment.
It is unlikely that you will need to make any lens adjustments at this visit. Also, it’s important to have an open dialogue regarding how the first night went while trying to mitigate any challenges identified at this point. In addition, if the patient appears to be significantly undercorrected at this visit, be sure to offer a solution, such as temporary soft lenses to correct vision until the full treatment effect has been achieved.
If all clinical data are favorable, schedule weekly follow-ups until the full treatment effect is reached, repeating the same protocol as the 1-day visit. In most cases, patients will achieve full treatment by 2 weeks, although some may take up to 4 to 5 weeks, depending on their initial refractive error.
Note that patients only need to wear their lenses into the office on the 1-day visit, but advise them to bring the lenses to each visit.
Handling complications from Ortho-K lenses
Undoubtedly, there will be times when the application and removal process doesn’t go smoothly, and additional support is needed. In my experience, most children tap out after 30 to 45 minutes of training; remain understanding, and allow the family to return for additional sessions if success isn’t achieved at the first scheduled appointment.
Training videos and/or written materials reiterating the instructions given in-office can be helpful for these individuals to review at home before returning. Some patients will likely need their parents' support for the first several weeks, transitioning to independent handling once they are ready.
If fitting challenges are encountered, i.e., if the lens fit is not close to ideal at the dispensing visit, do not dispense it. Make any necessary changes early on and then allow the lens to treat the eye for a minimum of 2 weeks before altering the fit. After the 2-week mark, if there is poor treatment or under-treatment, make the necessary changes for your chosen design based on the fitting guide or advice from the consultation team.
Marketing orthokeratology lenses
Traditional marketing strategies like newsletters and patient brochures are helpful, but one of the easiest ways to market Ortho-K is to simply DO IT on one patient. Orthokeratology patients are oftentimes the happiest patients in your office; they suddenly are free from daytime correction, and they LOVE talking about it to their friends and family! These patients typically become the biggest advocates for you and your office.
Another great way to market Ortho-K is by fitting as many of your staff members as possible. The organic conversation that flows between a team member and an interested patient is invaluable. In addition, connecting with the parents of sports teams—especially water sports and gymnastics—may yield numerous eligible Ortho-K patients.
Integrating Ortho-K into existing services
Because Ortho-K is a widely accepted option for myopia management, it should be one of the foremost options presented to families interested in this service. The advantages of Ortho-K over other options include freedom from daytime correction, the ability for parents to manage contact lenses entirely at home, and easier handling for new wearers.
Since Ortho-K is a novel concept to both patients and staff alike, be sure to spend adequate time training your entire team about the basics. Every staff member should at least be able to explain the basic principles, with the front desk and technician team being more thoroughly educated.
Staff training can take many forms: centering staff meetings around the principles of Ortho-K, enrolling your staff in formal online training classes, or outsourcing the training to a representative from your chosen lens manufacturer. To further enhance familiarity, allow staff members in the exam when you are discussing Ortho-K with prospective families.
Staff can also play an integral role in presenting Ortho-K to patients by identifying potential candidates when scheduling patients, as well as during pretesting. Once in the exam lane, the staff can open up the conversation about Ortho-K as a potential option and let the doctor provide additional details after the exam.
If a team member is particularly well versed in Ortho-K, they may be able to communicate the details in lieu of the doctor. This can be a significant time saver for physicians in busy practice settings.
Equipment considerations for Ortho-K lenses
To allow for the absolute best clinical results, a corneal topographer is essential. For many designs, simple keratometry values are sufficient, but proper troubleshooting requires a detailed topographical map. This is true because the same visual acuity could be the result of several different fitting issues, which can only be differentiated by topography.
Nowadays, there are combination devices specifically designed for practitioners offering myopia management. The Myopia Master from Oculus and the MYAH from Topcon are examples of combination devices offering both a topographer and biometer, amongst other features in one device.
Establishing a fee structure for orthokeratology
When establishing fees for Ortho-K, be sure to consider the cost of the lenses and your chair time. You can expect an average of five to six visits per patient per year. You may also want to build a spare pair of contact lenses into the fee for patient convenience, just in case a lens is lost or damaged. These fees can be presented to families as a global fee or a yearly subscription model.
The global fee is more convenient for the office since the fee is collected in full at the onset of the services. The subscription model consists of breaking down the global fee into monthly installments after an initial deposit is made. Although this is trickier for some offices to manage, it may be appealing to families who are more budget-conscious.
The final word
While orthokeratology was once considered a niche contact lens specialty within clinical practice, it has evolved substantially since those early days. At present, Ortho-K represents a frontline option for myopia control, and often the initial option amongst both parents and children.
With the introduction of specialized equipment, simplified ordering processes, biocompatible materials, and the availability of vast clinical resources, implementation is more streamlined—and more critical for our patients—than ever before.
