Myopia Profile

Clinical

The Topcon MYAH – Q&A With Mario Teufl

 Posted on November 28th 2022 by Mario Teufl

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In this article:

Mario Teufl joins us to explain how he uses the Topcon MYAH in his practice for myopia management with its various functions.

Our new Q&A format is designed to explore a particular clinical topic, intervention, product or research paper with an expert. The Topcon MYAH is a unique multifunctional instrument that offers various functionalities in one, to help you manage patients with myopia as well as dry eye. We catch up with Mario Teufl, Optometrist from Austria, who has used these features in his practice for a number of years.

Q&A with David Kern (1920 × 1500 px) (1).png How do you utilize axial length data in your myopia management practice?Q&A with Mario (2).png There are several ways in which I use axial length data in my practice. First of all, I screen every child and young adult, whether or not they are a myope. The reason is to collect data to see what the average is in my area as there are differences in culture and regions. Secondly, I am using the Topcon MYAH instrument for all myopic children, which plots axial length data against Tideman's percentile curves to determine outcomes and direct further management. Thirdly, I use the data to monitor axial elongation in adult and high myopes, to see how axial elongation tracks against refractive changes. I also use axial length data to determine whether the patient's myopia is primarily due to their ocular refraction or axial elongation.

Axial length is the main metric we seek to monitor in myopia management, as it is most closely linked with the risk of vision impairment associated with increasing myopia.1

Axial length measurement can be considered as an absolute measure, where a measure of over 26mm appears to be linked with escalating eye health risk,1 and can also be compared in children to their peers who are age and ethnicity matched. To learn more, read our Science Review A tale of two studies measuring change to axial length in myopia.

This 2022 ARVO research abstract also explored the influence of age and ethnicity on axial length, while any influence of region is yet to be determined.

Q&A with David Kern (1920 × 1500 px) (1).png Do you consider corneal topography as a routine measurement for your young myopic patients? Q&A with Mario (2).png Of course! Topography is one of my routine measurements for young myopic patients, to measure and track corneal astigmatism. This is important not just for orthokeratology lens (OK lens) fitting but also myopia tracking. For OK lens fitting, I use the topographer and pupillometry features to confirm the lens prescription, such as calculating OK lens treatment zones with the pupil size reading. As the MYAH includes a wavefront analyzer, I am able to look at this data and the pupil size to check whether the patient could potentially have vision problems at night or at school.screen04.jpeg
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The images above are screenshots of the MYAH software provided to us by Mario. The first image shows corneal topography and the second, pupillometry outputs.

Mario mentions measuring topography routinely for his young myopic patients. Monitoring corneal curvature in myopia management can be useful to flag potential keratoconic patients early. As corneal astigmatism does not typically progress alongside spherical myopia progression,2 any increase in astigmatism that is corroborated by steepening topographical changes can be suspicious of ectasia and should be monitored closely and/or referred for intervention where required. The MYAH provides specific indices, calculated from topography, to support early identification and tracking of keratoconus risk.

For those who are orthokeratology (OK) lens fitters, the MYAH outputs to many of the main OK online calculators to support lens design. The pupillometry feature is an additional diagnostic output to consider in the emerging field of altering OK lens design in myopia control. While there are no clinical guidelines yet on how OK lens design should best relate to pupil size for myopia control fitting, one retrospective study has found a relationship between the topographical treatment zone diameter, pupil size and the myopia control effect. A randomized controlled trial altering OK lens back optic zone diameter - to modify the treatment zone diameter - has shown a promising additional myopia control effect in the initial phase of the study.3 Pupil size was measured, but any interaction between pupil size and myopia control was either not present or not reported.

Q&A with David Kern (1920 × 1500 px) (1).png Do you prefer using growth curve data or absolute axial length measures in your clinical decision making, or both?Q&A with Mario (2).png I use both of them. Firstly, I look at which percentile of the growth curve my patient occupies. Then, I compare the absolute measurement of axial length change with the research data averages. I am also collecting overall axial length data for patients in my practice, to track their outcomes for my own investigations. Screenshot-2022-10-31-at-2.33.37-PM.png

The image above is a screenshot of the MYAH software provided to us by Mario. This shows an axial length growth chart with longitudinal patient data plotted along the chart in yellow. In this example, the percentile outcome was right at the top of the range but in more recent times appears to be tracking down over lower percentiles, likely due to myopia treatment.

The Erasmus research group in the Netherlands has described using axial length percentile charts to determine treatment success, which is observed when there is a reduction or tracking downwards of the percentiles.4

The MYAH incorporates the latest growth curve data from the Erasmus study group, going beyond their original growth curves published in 20185 to include an homogenous data set following the same children throughout.

One research abstract6  has applied this technique to the clinical trial data of the dual-focus concentric MiSight 1 day contact lens, and found that the control group followed their percentile line, while the treatment group showed a reduction of around 10 percentile points over the three years of the study. Read more in our Science Review of this research.

Q&A with David Kern (1920 × 1500 px) (1).png How do you explain the results provided by the Topcon MYAH to parents and patients?Q&A with Mario (2).png First of all, I explain what I am doing so the patient and parents are always involved in the process. While I am taking measurements, I will explain what I am doing and why. Next, I show them the growth curves on the Topcon MYAH and describe what they are seeing. I input the prescription and show them the measured points on the slope. I inform them that the average axial length is based on age, and explain the axial length growth percentiles as being similar to body height percentiles. I let them know the importance of repeat measurements. Then, I will go back to the analysis where we talk about the risk factors, genetics and consolidate the data. We also print out the myopia control report for the patients and their parents.

The images below are outputs of the MYAH report, provided to us by Mario.

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Q&A with David Kern (1920 × 1500 px) (1).png What sort of questions do parents typically ask about the reports provided by the MYAH?Q&A with Mario (2).png First of all, the parents want to know the likelihood of their children progressing into high myopia. The second most common question would be on the treatment options for their children. I usually present the IMI chart to the parent and patient, to explain the latest options and their efficacy. The third question often pertains to how long the treatment will be and whether it will stop or reduce myopia. I explain that we can't reverse myopia or stop its progression but can slow it down. The last question is typically about the cost. However, this is usually for family budgeting and not to rule out treatment options. Most of the time they are overwhelmed with all of this new information. We also supply an additional practice brochure to supplement the information from the MYAH report.Q&A with David Kern (1920 × 1500 px) (1).png Are you incorporating dry eye assessment into your myopia management? Q&A with Mario (2).png Yes, I do it for all my patients who undergo contact lens treatment. I do a full dry eye assessment before and during their treatment. The dry eye tool in the Topcon MYAH allows me to compare the quality and quantity of the tear film before and after contact lens fitting. I can also compare the result before and after use of medication and eye drops. If I am managing a contact lens wearer, I am obliged to assess their tear film. Even if the patient is not a contact lens wearer, prolonged amounts of near work can also affect the tear film so we should always perform dry eye assessments.screen05.jpeg

This screenshot image shows a tear break-up time assessment on the MYAH. Dry eye can be multifactorial, and it is common in children and teenagers. To learn more on this, read our Science Summary on the relationship as found in recent research. For an overview of how these two fields of practice interact, read our clinical article Dry Eye in Myopia Management.

Meet the Authors:

About Mario Teufl


Mario is an Austrian Optometrist. He completed the Master of Science in Pennsylvania College of Optometry and Salus University in 2005. Mario is the local president of the board of optometry in Carinthia. He has his own practice and a contact lens studio since 1998. Besides carrying out comprehensive eye examinations, he also practices myopia management. He has 15 years of experience in fitting Orthokeratology lens (OK lens). A year ago, he was the coordinator in the DACH region for the European Academy and in charge of OK lens and Myopia Control.  He is never tired to share his passion about his job and to inspire fellow optometrists.

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