Topography-Based Fitting Can Improve OrthoK Efficiency

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January 18, 2023

By Ashley Tucker, OD, FAAO, FSLS, ABO Diplomate

As new technology becomes available, the fitting process has become streamlined, improving the first fit success rate and reducing chair time for each patient. 

When fitting patients with orthokeratology lenses, there are three primary ways to go about finding the perfect lens for each patient: diagnostic fitting, empirical fitting, or topography-based fitting. I’ve been fitting patients in OrthoK lenses for over a decade, and in that time, I’ve gained experience with all three methods. As new technology becomes available, the fitting process has become streamlined, improving the first fit success rate and reducing chair time for each patient. 

Diagnostic Fitting vs. Empirical Fitting vs. Topography-Based Fitting
Diagnostic fitting was how I initially starting fitting orthokeratology over 10 years ago, and I still do so from time to time. Fitting OrthoK lenses this way allows me to determine immediately if the patient can tolerate the lenses and if OrthoK is a good option. I can also dispense lenses on the same day that OrthoK is discussed if I have the appropriate lenses in stock.

However, fitting lenses this way can also be time consuming because multiple lenses may have to be tried on the patient before an ideal lens is found. I have a very extensive fitting set, but there are still times I don’t have the exact lens the patient needs. On the rare occasion when this happens, we then have to wait for the correct lenses to arrive in order to continue the fitting process. 

Empirical fitting with a calculator has been my fitting method of choice for the last several years. Due to the sophistication of the calculator, most lenses designed by the calculator provide a very good first lens for the patient in terms of fit and visual acuity. In only about 20% of my patients, I have to modify the lenses to provide the patient with a better treatment zone or better centration. As I have learned the nuances of the calculator, I now know which parameters to alter in order to improve my first lens success rate — this is most often fitting slightly larger in diameter than the suggested lens.

My first experience with topography-based fitting came as a principal investigator for the Evaluation of the Comfort of Orthokeratology Lenses Fit Using a New Software Study. I found it to be incredibly efficient, with most fits being successful after one design attempt. On the rare occasion that troubleshooting was necessary, one additional lens provided an ideal fit in all my patients. One major benefit of topography-based fitting is the potential for enhanced customization of the lenses, since they are designed based on the curvature of the entire cornea instead of just a few data points. As a result, theses lens designs could provide superior vision and comfort.

Topography-based fitting may be a better option for new fitters as they gain confidence in the process because this type of fitting requires less decision-making and experience. Ultimately, I foresee this type of fitting saving chair time for all fitters!

Getting Staff Involved
Utilizing topography-based fitting for OrthoK has allowed me to delegate this step to my staff. I have designated staff members who take topographies for my OrthoK patients, and they all learned the system directly from a trainer from the topographer’s manufacturer. At this point, I have one primary staff member who is the most well trained on the topographer, and she’s responsible for teaching any new staff members. As a team, we review general topography techniques and go over troubleshooting on a quarterly basis, or as needed. 

My most important advice for staff members when taking a patient’s topography is to prioritize getting an image that’s high quality. With young patients, this might mean taking several images to make sure there’s at least one or two of each eye that can be used. Two of the keys to clear images are having a smooth ocular surface and ensuring there are a minimal number of eyelashes visible in the image (especially superiorly). 

Visavy Software Simplifies Topography-Based Fitting
In utilizing topography-based fitting for OrthoK patients, I’ve been able to try CooperVision Specialty EyeCare’s Visavy software for both Paragon CRT and Paragon CRT Dual Axis lenses. The software is installed remotely on a computer in your practice to integrate with your topographer. It’s compatible with the top 10 topographers on the market right now. My patient data show that using Visavy I was able to achieve 97% first fit success compared to 80% success with empirical fitting.

As a practitioner, you take the topography of the patient’s eye and then import that data into the Visavy software. From there, multiple algorithms make design recommendations and also show simulated fluorescein patterns. While the software will automatically generate these recommendations, you can still use your own knowledge and experience of OrthoK to make any changes to the lens recommendation that you think are necessary. 

For practitioners, like myself, who still want to utilize the empirical fitting process, the Visavy software makes that possible — it can be either topography-based or topography-guided fitting. Once you have the empirical data, you can input it into the Visavy software and create the OrthoK lens design that way. 

The software itself is very easy to navigate, and it streamlines the entire process of fitting an OrthoK lens — the design, customization, and ordering. After finalizing the lens design, there’s the option to order the lens right within the software itself, as well as track the shipment from the moment it’s ordered until it arrives at your practice. 

For practitioners who might be newer to OrthoK, Visavy also allows you to connect with consultants who can walk you through a complicated fit, offer guidance on the fitting and design process, and answer any questions about fitting. There’s often a lot of trepidation or anxiety around starting out with specialty lenses. However, knowing the consultants are there to assist you can help get over that hurdle and, over time, become a really experienced, confident fitter. It’s not training wheels for the learning process — it’s more like an accelerant. For seasoned practitioners, Visavy serves as a supplement to the knowledge that you already have. The extra guidance and support are just added bonuses. Whether you’re a veteran OrthoK fitter, or just starting out, Visavy can be beneficial to you, your practice, and your patients.


Dr. Ashley Tucker graduated from the University of Houston College of Optometry in 2010 and completed a Cornea and Contact Lens Residency at UHCO in 2011. Dr. Tucker is a partner at Bellaire Family Eye Care, a private practice in the Houston, Texas, area where she primarily manages patients in need of specialty contact lenses and myopia management. She is also a Visiting Assistant Professor at UHCO and is the course master for the Ophthalmic Optics laboratories. In addition, Dr. Tucker is a member of the Speaker’s Bureau for the Specialty Division of Bausch + Lomb, a consultant for CooperVision, and a lecturer for the STAPLE (Soft Toric and Presbyopic Lens Experience) program.


To learn more about the Visavy software, click here

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