Power Profiles of an extended depth of focus contact lens for Myopia Management

Power Profiles of an extended depth of focus contact lens for Myopia Management | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Power Profiles of an extended depth of focus contact lens for Myopia Management Veronica Noya-Padin, Annabelle Mawhinney, Phillip Buckhurst, Hugo Pena-Verdeal, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7434789/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Purpose: To characterise the optical power profiles of an extended depth of focus (EDOF) contact lens (MYLO, Mark’ennovy) for myopia management across its full range of labelled powers and fitting parameters. Methods: Power profiles of 91 MYLO lenses were measured using the NIMOevo® instrument. Lenses ranged in labelled power from –1.00 to –10.00 D, total diameters (TD) from 13.50 to 15.50 mm and back optic zone radii (BOZR) from 7.1 to 9.8 mm. Central thickness (CT) was assessed using spectral-domain optical coherence tomography. Lens power profiles were fitted with piecewise cubic splines, and peaks and troughs were identified using both semi- and fully automated inflection point detection. Zernike polynomial fitting, applied at enhanced resolution, was used to derive power within the central 0.50 mm radius. Results: All lenses demonstrated a damped sine-wave power profile, featuring three consistent peaks and troughs superimposed on a general trend toward peripheral minus power. The location and relative magnitude of these features remained highly consistent across all combinations of lens power, TD, and BOZR. Central zone analysis revealed a mean relative hyperopic defocus of 1.24 ± 0.79 D within the central 0.25 mm radius, followed by a myopic shift of 0.41 ± 0.38 D in the 0.25 - 0.50 mm annulus, resulting in a near-emmetropic outcome (0.08 ± 0.38 D) across the full central 0.00 - 0.50 mm region. CT was not correlated with labelled power. Conclusions: The MYLO lens demonstrates a stable and predictable optical profile across a broad range of fitting parameters, indicating that changes in lens power or parameter do not impact its optical performance. The study highlights the need for refined standards in the evaluation of power profiles of EDOF CLs. Extended Depth of Focus (EDOF) power profiles myopia myopia management contact lenses Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Key points The MYLO EDOF contact lens demonstrates a consistent optical power profile, comprising alternating myopic peaks and hyperopic troughs with diminishing amplitudes toward the lens periphery. Zernike polynomial fitting enabled power estimation within the central 0.5 mm radius, revealing a rapid progression from hyperopic to myopic defocus. Consistent power profiles across powers and parameters confirm predictable optical performance of the lenses, however underscore the need for updated standards to evaluate non-zonal EDOF lens designs. Introduction To address the rapid rise in myopia prevalence,[1] optical interventions continue to be developed.[2] Although the precise mechanisms underlying myopia progression remain unclear, evidence suggests that refractive development relies on a visual feedback process in which peripheral retinal input regulates axial growth.[3] Specifically, modulation of peripheral retinal image defocus and contrast plays a crucial role in myopia management [4]. Given their demonstrated efficacy, [5, 6] multifocal contact lenses (MFCLs) have emerged as a widely adopted strategy for myopia management. Power profile mapping of MFCLs used for myopia management is essential for the development and clinical assessment of optical designs, as the power profile directly influences retinal image formation. MFCLs typically exhibit rotational symmetry, but their power profiles vary depending on the design.[7] Key factors characterising these profiles include the location of distance and near correction zones, the magnitude of near addition power, transition diameters, and the rate of power change. MFCLs can be broadly classified into two categories: lenses with an optical gradient profile and those with an alternating or stepped profile.[8] Optical gradient profile designs feature a progressive power variation, with relative minus or plus power increasing toward the periphery in centre-near and centre-distance lenses, respectively. In contrast, MFCLs with an alternating or stepped profile exhibit abrupt power changes either in the form of concentric rings or with a single step between the central and peripheral power.[9] Unlike these MFCL designs, which provide discrete focal points, extended depth of focus (EDOF) lenses have a continuously changing power across their surface, fluctuating between myopic and hyperopic defocus. Consequently, there are no discrete distance and near focal points, and instead they exhibit a continuum of foci rather than distinct foci. Significant differences exist among EDOF lens designs used in myopia management. For instance, the NaturalVue® lens (Visioneering Technologies, USA) employs a catenary curve design, where the central region corrects the refractive error, followed by a rapid peripheral power increase that induces myopic defocus.[10] In contrast, the MYLO lens (Mark’ennovy, Spain) features a non-monotonic design with no discrete power zones. Instead, its power varies above and below the normal mean in an aperiodic pattern, with gradual transitions between power changes and a relative negative power shift toward the periphery.[11] Ehrmann noted that an inherent limitation of all power mapping instruments and methods is their inability to accurately measure close to the optical centre.[12] It has been previously reported that power measurements close to the optical axis can be unstable due to the use of a 1/r weighting factor, where r is the radial distance from the optical centre. [13] As r approaches zero, this factor increases greatly, amplifying even minor measurement noise. To address this issue, investigators using the NIMOevo®instrument have often excluded the central 0.5 mm radius from their analysis.[8, 13, 14] While this omission has minimal impact on the evaluation of concentric bifocal lenses, where the central power tends to remain stable, it poses limitations for the assessment of EDOF lenses. These designs frequently show complex power variations in the central zone — with some progressing rapidly from myopic to hyperopic defocus, and others showing the opposite trend. Capturing these central optical features is therefore essential to fully characterise EDOF lens performance. While ISO standards offer guidance on interpreting the power profiles of MFCLs,[15] they do not currently address EDOF lenses. Given the diversity in EDOF lens designs, there is no standardised method for evaluating their power profiles. As a result, the optical parameters influencing the effectiveness of these lenses for myopia management remain unclear. Despite the increasing use of MFCLs for myopia management, predicting individual outcomes remains challenging. Physiological factors such pupil size [16-18] and retinal shape [19, 20] as well as modifiable variables related to MFCL design and fit [21-24] are likely to play a significant role. Typically, contact lens (CL) fitting parameters are available only in discrete diameters and base curves, which limits optimisation of the fit on the individual eye. The MYLO MFCL addresses this limitation by offering a wide range of total diameters (TD) and back optic zone radii (BOZR). However, to the authors’ knowledge, no comprehensive studies have investigated the impact of different MFCL parameters on their optical profiles. Therefore, the objective of this study was to evaluate the power profiles of different combinations of power and fitting parameters for a specific myopia management EDOF CL (MYLO, Mark’ennovy). The study compares a semi-automated and a fully automated method for determining the locations of power changes and explores their relationship with base lens power and fitting parameters. Methods Contact lenses The MYLO Silicone Hydrogel EDOF CL is a CE marked soft, monthly disposable CL approved for myopia management. The CL is manufactured using a lathe process, allowing for a wide range of parameters: TD (13.50 to 15.50 mm in 0.50 steps), BOZR (7.1 to 9.8 mm in 0.3 steps) and spherical powers (-0.25 to -15.00 D in 0.25 D steps).[25] The fitting parameters of the lenses included in the study were chosen based on two criteria: Varying lens power with fixed TD and BOZR parameters. To assess changes in the power profile with CL power, two fixed TDs (14.00 mm and 14.50 mm) as well as two BOZRs (8.0 mm and 8.6 mm) were selected whilst assessing the power (-1.00 to -10.00 D in 1.00 D steps). These parameters were chosen based on their common usage in myopia management and align with those observed for other myopia management MFCLs such as MiSight® 1 Day (8.7/14.2 mm), Bloom Day (8.3/14.5 mm), and Amiopik (8.7/14.2 mm) lenses.[26-28] Additionally, extreme parameter values (7.1/13.50 mm and 9.8/15.00 mm) were included and analysed across the same power range to evaluate consistency (Table 1). Varying TD and BOZR parameters with fixed lens power To evaluate the impact of fitting parameters on the power profiles of the MFCLs, all commercially available combinations of BOZR and TD were assessed using a fixed power of -3.00 D. BOZR was varied in 0.3 mm increments, spanning the available range from 7.1 mm to 9.8 mm, while TD was varied in 0.5 mm increments, from 13.50 mm to 15.50 mm (Table 1). Table 1. Lens parameter configurations used in the study. TD = Total Diameter. BOZR = Back Optic Zone Radii. Power (D) TD (mm) BOZR (mm) Varying lens power with fixed TD and BOZR parameters –1.00 to –10.00 in 1.00 steps 13.50 7.1 –1.00 to –10.00 in 1.00 steps 14.00 8.0, 8.6 –1.00 to –10.00 in 1.00 steps 14.50 8.0, 8.6 –1.00 to –10.00 in 1.00 steps 15.00 9.8 Fixed lens power with varying TD and BOZR parameters -3.00 13.50 7.1 to 9.2 in 0.3 steps -3.00 14.00 7.4 to 9.5 in 0.3 steps -3.00 14.50 7.7 to 9.8 in 0.3 steps -3.00 15.00 8.0 to 9.8 in 0.3 steps -3.00 15.50 8.3 to 9.8 in 0.3 steps As per ISO 18369-3,[29] prior to measurement, each CL was removed from its blister pack and immersed in standard phosphate-buffered saline (PBS) (n=1.334) at a temperature of 20.0°C (± 1.0°C) for at least 30 minutes. Assessment of contact lens thickness CLs were placed within a conical glass tube filled with fresh PBS within an intraocular lens holder (Trioptics, www.trioptics.com), with the convex side facing upward and the CL edges resting on the holder. Imaging of the CLs was achieved using the Ganymede™ GAN312 Spectral Domain Optical Coherence Tomography (SD-OCT) system with the addition of an IMM4-SP1 Z-spacer (Thorlabs, www.thorlabs.com), equipped with a 54 mm effective focal length scanning lens optimised for immersion evaluation. Axial and lateral resolution in water of the instrument is 4.5 µm and 12 µm, respectively. The image acquisition involved averaging 25 scans, with an A-scan rate of 10 kHz.[30] Optical Coherence Tomography (OCT) images were corrected for the refractive index of the CL material (MYLO, n=1.376). CT of the CL at the apex was measured on each OCT image using ImageJ (v1.54h, https://imagej.net/ij/). Power profile assessment The NIMOevo® (Lambda-X, www.ophthalmics.lambda-x.com) is a commercially available optical device designed for the metrology of CLs.[8] Utilizing Phase Shifting Schlieren technology, it measures wavefront aberrations using collimated light at a wavelength of 546 nm, enabling the extraction of optical power across the CL in dioptres. Specific advantages of power profile measurement with the NIMOevo® over traditional Hartmann-Shack aberrometers include the higher spatial resolution offered and have been discussed extensively in previous studies.[8, 31, 32] For each measurement, the CL was immersed in PBS within the manufacturer-provided quartz cuvette and positioned over the internal CCD camera. Measurements were taken at the geometric centre of the CL with the following settings: aperture diameter of 10 mm, liquid refractive index (PBS, n=1.334), CLs refractive index (MYLO, n=1.376), the nominal lens diameter (TD of the test lens), BOZR of lens, and centre thickness as measured by the OCT system. A "wet to dry" conversion was applied. The averaged radial power profile across the 10 mm aperture (260 individual measurements per CL) was exported in CSV format. Radially averaged profile outputs exhibit symmetry about the optical centre (OC). However, as previously reported, inaccuracies arise in the vicinity of the OC due to the application of a 1/r weighting factor, where r denotes the radial distance from the OC[13]. At small radial distances, this factor increases sharply, amplifying even minimal measurement noise[33]. To address this, rather than excluding data within the central 0.5mm radius as done in other studies [13, 33, 34], the measurement process was adapted to improve the accuracy and stability of central power measurements, as described in the central zone power assessment section. Central zone power assessment This study adopted a Zernike polynomial fitting approach rather than relying on traditional radial power maps. Zernike polynomials up to 6th order were used to reconstruct the wavefront, from which spherical power was derived within precisely defined zones. Accurate Zernike fitting depends on both the order of the polynomials and the density of data points within the analysis zone.[35] Under default settings, the NIMOevo® system samples at a lateral resolution of 40 microns. For this study, the manufacturer modified the settings to achieve a 20-micron resolution, significantly increasing the number of points within the central region and improving the fidelity of the Zernike fit. However, this increased the time taken for each scan. Using this enhanced resolution, spherical power was measured and then calculated three times for the following aperture diameters: Zone 1: Central 0.50 mm diameter (0.25 mm radius) Zone 2: Annular region from 0.50 mm to 1.00 mm diameter (0.25 - 0.50 mm radius) Zones 1 & 2 combined: Full 0.00 - 1.00 mm diameter (0.00 - 0.50 mm radius) This method allowed for more robust and reliable assessment of central optical power, particularly in EDOF lenses where central variation is a defining feature of the design. Data analysis The average radial power profile data from the NIMOevo® was imported into Microsoft Excel. The CL generates an aperiodic power profile which appears akin to a damped sine wave with three distinct peaks of progressively reducing positive power each followed by a trough of greater negative power. In addition, there is a general slope towards increasing negative power in the periphery (Figure 1). For each lens the lateral locations and the dioptric power of the three troughs and peaks were identified by fitting spline curves to the power profile and then determining the inflection points of these curves using MATLAB (MathWorks, USA).[36] Since no standardised methodology exists for assessing power profiles of EDOF lenses and determining the positions of the peaks and troughs two methods were employed. Initial analysis for both techniques required a piecewise cubic spline curve to be fitted to each power profile. The first method utilised a semi-automated process to identify the points of inflection along the cubic spline curve. Through visual inspection, an assessor then subjectively determined which of these inflection points corresponded with each peak and trough of the power profile. The second method, which was fully automated using Python, applied a smoothing function to the cubic spline curve to remove erroneous inflection points until just the six inflections were present thus removing the requirement of a subjective assessment.[37] The dioptric magnitude of each peak and trough and the central zones were determined and then the labelled lens power was subtracted from the value to determine relative magnitude. Descriptive statistics (mean and standard deviation) were used to express the locations of the peaks and troughs. A two-way repeated measures ANOVA was used to determine if a significant difference in the locations of the peaks and troughs existed between the two methodologies employed for determining the inflection points. Pearson’s correlation coefficient was used to assess the relationships between power zone location and peak amplitude, both calculated by semi-automated and fully automated processes, with lens power and fitting parameters (TD and BOZR). Results Power profiles Figure 2 shows the power profiles for a range of lenses where the TD and BOZR were kept constant, but lens power was systematically assessed. A consistent pattern of fluctuating power, evident as three peaks and troughs, was observed for all combination of lens parameters. The magnitude of the peaks and troughs progressively reduced with increasing distance from the centre. Figure 3 shows power profiles of -3.00D lenses with varying TD and BOZR. Yet again a consistent pattern of power fluctuation was evident for the range of parameters assessed. Varying TD and BOZR parameters with fixed lens power Comparison between semi-automated and automated methods for determining the position of the peaks and troughs Both methods created equivocal results (F = 0.116, p = 0.733) with slightly less variance found with the fully automated process (Fig. 4 ). The position of the peaks and troughs was consistent throughout the power ranges and fitting parameters except for the first trough which exhibited double the variance of the other peaks. Relationship between peak/trough location, relative magnitude, lens power, and fitting parameters Using the semi-automated method, weak correlations (|r| between 0.200 and 0.390) were observed between power and both the first peak (r = − 0.207) and the third peak (r = − 0.363), as well as between power and the third trough (r = − 0.337). In addition, the third trough showed weak correlations with BOZR; (r = − 0.280) and TD (r = − 0.214). In contrast, the fully automated method revealed that power was weakly correlated with the first peak (r = − 0.278), the third peak (r = − 0.241), and the second trough (r = − 0.287). Moreover, moderate correlations were found between power and both the second peak (r = − 0.419) and the third trough (r = − 0.435). No other correlations reached statistical significance (p < 0.050) (Supplementary, Table 1 ). Comparison between semi-automated and automated methods to determine the relative power of the peaks and troughs Relative power was similar when using both semi-automated and the automated method (F = 0.019, p = 0.892), with less variance found with the fully automated process (Fig. 5 ). The first trough exhibited the highest level of variance of all peaks and troughs. Using both the automated and semi-automated analysis methods, a significant weak correlation (|r| between 0.231 and 0.397) was observed between labelled lens power and the relative power of all the peaks and troughs with the exception of the 1st trough (r = 0.042, p = 0.696). A significant correlation was found between labelled lens power and the power of Zone 1 (r = 0.280, p = 0.007) and Zone 2 (r = 0.212, p = 0.044), but not Zone 1 & 2 combined (r = 0.200, p = 0.057). No other significant correlations were revealed (p < 0.050) (supplementary, Table 2). Central lens thickness Average CT was 0.136 ± 0.02 mm. No correlation was found between CT and labelled CL power (r = 0.100, p = 0.342). Discussion To the authors’ knowledge, this is the first published investigation to assess a myopia management contact lens across the widest reported range of lens powers and fitting parameters. The primary aim of this study was to evaluate the consistency of the MYLO lens design across its power range and fitting options. Detailed analysis of refractive power profiles in MFCLs provides crucial insights into how these designs alter the retinal image—and their potential role in myopia management. Recent evidence suggests the importance of the location of induced retinal blur in reducing axial length progression.[ 38 ] Given its significance, it is essential to identify the region of the MFCL that provides additional plus power and assess whether it corresponds to the retinal area (6–9°) recognised as crucial for slowing myopia progression. Since this retinal zone plays a key role in myopia management, evaluating the consistency of zone locations across the power range is important to detect potential optical variations in the MFCL that could impact its effectiveness. Within the central 3 mm radius, the CL maintains a highly consistent optical profile, demonstrating a damped sine wave pattern superimposed on an overall negative curve. The locations of the troughs and peaks, as well as the relative power of each zone, peak and trough, remained largely consistent across all evaluated CLs. As expected, the locations and powers of the peaks and troughs are independent of the BOZR. Of particular interest is that these locations and powers are also consistent regardless of the TD of the lens. This optical consistency offers both advantages and potential drawbacks. A key advantage is that practitioners can transition between different lens powers and fitting parameters without significantly altering the relative positive visual loads that contribute to myopia management. This predictability ensures that myopia management strategies remain stable regardless of modifications to lens parameters. An alternative approach could involve adjusting troughs and peak locations based on TD, shifting them outward as lens diameter increases. This would be relevant if horizontal iris diameter were strongly correlated with axial length. However, Magnetic Resonance Imaging (MRI) studies have demonstrated a weak association between anterior and posterior segment dimensions.[ 39 ] Given the challenges in predicting axial length from anterior segment parameters, maintaining a consistent optical profile across different lens diameters appears to be the preferred strategy. A uniform and predictable optical design may provide better myopia management by ensuring consistent retinal defocus regardless of lens fitting variations. Interestingly, the overall negative curve (superimposed on the damped sine wave), is indicative of negative spherical aberration, demonstrating that the MYLO MFCL incorporates an aspheric design, as evidenced by the stable level of negative spherical aberration across the power range.[ 40 ] This contrasts with the spherical MiSight® 1 Day CL, which exhibits increasing negative spherical aberration with higher base powers.[ 34 , 41 ] The different optical designs of these CLs are particularly relevant when considering how they influence the mechanism to slow down axial growth. The NIMOevo® system evaluates light travelling along the optic axis, yet myopia progression is believed to be more influenced by off-axis light. Consequently, future investigations should explore the role of asphericity in both orthogonal and oblique light paths to better understand its impact on myopia progression. The MYLO CL profile demonstrates 1.24 ± 0.79 D of central hyperopic defocus within the central 0.25 mm radius, followed by 0.41 ± 0.38 D of myopic defocus within the 0.25–0.50 mm annulus. When assessed together, these two zones provide a result close to the labelled power (0.08 ± 0.38 D). Beyond this, the lens exhibits three peaks and troughs, transitioning from central myopic defocus to progressively more hyperopic defocus toward the periphery. In addition to this progressive shift, the amplitude of the peaks and troughs decreases with increasing radial distance. This highlights an important distinction between the continuous power profile observed with such EDOF MFCLs and the stepwise power changes typical of zonal designs. The ability to analyse continuously progressing CLs without predefined zones represents a methodological strength of this study, as it enables precise characterisation of the positions of peaks and troughs and the relative power variations between them.[ 8 ] This strength is further emphasised by recent studies highlighting the limitations in measuring distance zones in EDOF lenses, as their multiple power variations prevent a clear definition of these zones. This contrasts with conventional centre-near progressive lenses, where the distance zone is more clearly defined, and the evaluation models are simpler, as they only require analysing a single progressive profile rather than multiple power peaks.[ 8 ] The optical power distribution of EDOF design CLs is not accurately described in terms of addition, as this does not capture the reality of the optical profile. Addition is a change in power that remains constant in a particular area of the CL compared to another area of lower power. A myopia management CL that can be defined using this terminology is the MiSight® 1 Day MFCL. However, power in EDOF CLs undergoes continuous fluctuations in the form of oscillatory cycles, making it unfeasible to delineate a region of constant power. Consequently, EDOF design CLs, such as the MYLO, are defined by troughs and peaks in their power profile and are therefore better described by the relative power of troughs and peaks rather than by the concept of addition. A key strength of this study lies in the use of the NIMOevo® system. Optical power measurements within the central optical zone (0.50 mm radius) are known to be unreliable, and Lambda-X explicitly advises against interpreting data in this region due to inherent limitations in the system’s measurement algorithm. This constraint is consistent with previous studies, which have identified similar issues in this and other devices that rely on algorithmic power calculations.[ 8 , 13 , 14 ] To mitigate this limitation, the present study analysed the central region using two discrete zones, deriving optical power from Zernike polynomial fitting rather than radial power profiles. This approach revealed a notable region of hyperopic defocus within the central 0.25 mm followed by low myopic defocus. However, the application of Zernike polynomials in this context must be approached with caution. Accurate fitting requires sufficient spatial resolution—specifically, an adequate number of data points across the area of interest. While the NIMOevo® system allows adjustment of settings to increase data point density beyond factory defaults, the polynomial fit remains a critical factor in data interpretation. The principal advantage of Zernike fitting in the central 1 mm diameter lies in its robustness against the mathematical instabilities inherent in power profile calculations at very small radii. When using the radial power maps as r approaches zero, measurement noise is amplified, often resulting in spurious spikes or oscillations. Utilising a polynomial fit models the entire 2D wavefront surface and derives local power analytically from the fitted coefficients, eliminating the singularity at r = 0. Because the fit uses data from the entire aperture, the central estimate is constrained by a physically smooth wavefront model, reducing the influence of localised artefacts and sparse central sampling. This approach also retains the full 2D optical information, avoiding the loss of asymmetry and subtle aberration effects that occur when using a single averaged radial profile. The NIMOevo® system uses a 6th-order Zernike polynomial to fit surface deflections and derive power, which means fitting 28 coefficients (up to 6th order) to the data points. Given the enhanced 20µm resolution, even with a 0.5mm central diameter, there were sufficient data points to provide a fit resistant to noise. By combining high-density NIMOevo® sampling with Zernike fitting, the present study was able to obtain stable and plausible estimates of central optical power that would not have been achievable using the conventional power profile method alone. However, a 6th-order Zernike polynomial may be insufficient to fully capture the complex wavefronts produced by multifocal or EDOF CL.[ 42 ] To reduce potential fitting errors, this study limited the analysis to well-defined, narrow zones rather than attempting a global fit across the entire optic. This methodological choice enhances the reliability of the results by minimising distortions introduced by underfitting complex optical surfaces. Bodas-Romero et al. proposed four metrics for describing the power profile of a multifocal/EDOF CL. [ 43 ] However, three of these metrics required normalising the radial power profile to 0 D at the geometric centre—a problematic approach given the known unreliability of NIMOevo® measurements in this region. As a result, only their maximum addition point (MAD, equivalent to our first peak location) was independent of the central reference, yet no analysis was presented to determine whether MAD varies with labelled power. Furthermore, the absence of any curve fitting or smoothing means that all metrics based on a single maximum value were vulnerable to noise spikes, making their repeatability questionable. In contrast, our methodology avoids these pitfalls by combining high-density sampling (20 µm) with Zernike polynomial reconstruction of the 2-D wavefront and piecewise spline fitting of the radial profile. This removes the 1/r instability at small radii, constrains the central estimate using information from the entire aperture, and smooths out point-wise noise artefacts that could otherwise distort parameters such as addition magnitude or location. Importantly, our proposed metrics are not dependent on the central lens power. Consequently, our derived metrics, including the equivalent of MAD, are robust to local measurement artefacts and provide a more reliable representation of the true optical design. It is worth noting that the position and relative power of the first trough exhibited greater variance compared to other peaks, suggesting that this measurement may be affected by central-region limitations. Despite these constraints, both the semi-automated and fully automated methods employed in this study produced comparable results, with the automated approach demonstrating slightly lower variance. Finally, this study highlights a gap in existing ISO standards for MFCLs, aligning with previous reports.[ 8 , 13 ] Current guidelines do not account for continuously progressing lens designs such as the MYLO, which lack discrete optical zones. Standardisation of power profile analysis methods for these CLs would be beneficial for both research and clinical applications, ensuring more accurate characterisation of their optical properties. Conclusion The MYLO CL exhibits a highly consistent optical design across its power range and fitting parameters, indicating that changes in lens power or parameters do not impact its optical performance. The findings of this study provide valuable insights into the lens’ optical properties and suggest that a stable, predictable power profile may be advantageous in maintaining consistent myopia management outcomes. Future research should focus on evaluating off-axis light distribution and refining methodologies for characterising non-zonal MCFLs to further optimise myopia management strategies. Declarations Disclosure The authors report no conflicts of interest and have no proprietary interest in any of the materials mentioned in this article. Author Contribution V.N-P., A.M., and H.P-V. collected data. V.N-P. and C.M. analysed data. V.N-P., A.M., P.B., H.P-V., S.H. and H.B. contributed to writing the manuscript and preparing figures. All authors reviewed the manuscript. Acknowledgements This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. University of Plymouth PhD fee waiver for Annabelle Mawhinney. 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Tan, Q., et al., Retinal image quality in myopic children undergoing orthokeratology alone or combined with 0.01% atropine . Eye Vis (Lond), 2023. 10(1): p. 21. Pope, J.M., et al., Three-dimensional MRI study of the relationship between eye dimensions, retinal shape and myopia . Biomed Opt Express, 2017. 8(5): p. 2386–2395. Li, Q. and F. Fang, Contribution of the retinal contour to the peripheral optics of human eye . Vision Res, 2022. 198: p. 108055. Rizzo, G.C., et al., Centration assessment of an extended depth of focus contact lens for myopic progression control . Cont Lens Anterior Eye, 2023. 46(1): p. 101533. Corpus, G., A. Molina-Martin, and D.P. Pinero, Efficacy of Soft Contact Lenses for Myopia Control: A Systematic Review . Semin Ophthalmol, 2024. 39(3): p. 185–192. Song, D., et al., Efficacy and adverse reactions of peripheral add multifocal soft contact lenses in childhood myopia: a meta-analysis . BMC Ophthalmol, 2024. 24(1): p. 173. Ruiz-Pomeda, A. and C. Villa-Collar, Slowing the Progression of Myopia in Children with the MiSight Contact Lens: A Narrative Review of the Evidence . Ophthalmol Ther, 2020. 9(4): p. 783–795. Noya-Padin, V., et al., Dehydration and physicochemical changes in myopia control contact lenses: influence of material and maintenance solutions . Cont Lens Anterior Eye, 2025: p. 102478. Ruiz-Pomeda, A., et al., MiSight Assessment Study Spain (MASS). A 2-year randomized clinical trial . Graefes Arch Clin Exp Ophthalmol, 2018. 256(5): p. 1011–1021. Pauné, J., et al., Changes in Peripheral Refraction, Higher-Order Aberrations, and Accommodative Lag With a Radial Refractive Gradient Contact Lens in Young Myopes . Eye Contact Lens, 2016. 42(6): p. 380–387. Walline, J.J., et al., A Randomized Trial of Soft Multifocal Contact Lenses for Myopia Control: Baseline Data and Methods . Optom Vis Sci, 2017. 94(9): p. 856–866. ISO, Ophthalmic Optics - Contact Lenses – 18369 in Part 3: Measurment Methods . 2017. Davidson, B.R. and J.K. Barton, Application of optical coherence tomography to automated contact lens metrology . J Biomed Opt, 2010. 15(1): p. 016009. Dominguez-Vicent, A., et al., Repeatability of in vitro power profile measurements for multifocal contact lenses . Cont Lens Anterior Eye, 2015. 38(3): p. 168–72. Monsálvez-Romín, D., et al., Power profiles in multifocal contact lenses with variable multifocal zone . Clin Exp Optom, 2018. 101(1): p. 57–63. Ehrmann, K., Pros and Cons of soft contact lens power mapping . Optometry & Contact lenses, 2024. 4(1): p. 28–34. Mawhinney, A.J., et al., Characterizing power profiles of a concentric ring multifocal contact lens for myopia management: a novel approach . Cont Lens Anterior Eye, 2025: p. 102454. Smolek, M.K. and S.D. Klyce, Goodness-of-prediction of Zernike polynomial fitting to corneal surfaces . J Cataract Refract Surg, 2005. 31(12): p. 2350–5. Law, E.M., et al., Predicting the Postoperative Addition Power of a Multifocal Intraocular Lens at the Spectacle Plane . J Refract Surg, 2021. 37(5): p. 318–323. Virtanen, P., et al., SciPy 1.0: fundamental algorithms for scientific computing in Python . Nature Methods, 2020. 17(3): p. 261–272. Swiatczak, B., H.P.N. Scholl, and F. Schaeffel, Retinal “sweet spot” for myopia treatment . Scientific Reports, 2024. 14(1): p. 26773. Kneepkens, S.C.M., et al., Eye Size and Shape in Relation to Refractive Error in Children: A Magnetic Resonance Imaging Study . Investigative Ophthalmology & Visual Science, 2023. 64(15): p. 41–41. Koh, S., et al., Efficacy of spherical aberration correction based on contact lens power . Cont Lens Anterior Eye, 2014. 37(4): p. 273–7. Bodas-Romero, J., L. Batres, and G. Carracedo, Power Profiles of Different Myopia Control Soft Contact Lenses . Eye Contact Lens, 2025. 51(6): p. 261–268. Del Águila-Carrasco, A.J., E. Papadatou, and P.J. Buckhurst, Measuring aberrations of multifocal and extended depth-of-focus intraocular lenses . J Cataract Refract Surg, 2019. 45(10): p. 1516–1517. Bodas-Romero, J., L. Batres, and G. Carracedo, Power Profiles of Different Myopia Control Soft Contact Lenses . Eye & Contact Lens, 2025. 51(6): p. 261–268. Additional Declarations No competing interests reported. Supplementary Files SupplementarytablesEDOF.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 25 Aug, 2025 Editor assigned by journal 25 Aug, 2025 Submission checks completed at journal 24 Aug, 2025 First submitted to journal 22 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7434789","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":506864413,"identity":"810ce38b-f96c-4691-8771-6217454156c6","order_by":0,"name":"Veronica Noya-Padin","email":"","orcid":"","institution":"Universidade de Santiago de Compostela","correspondingAuthor":false,"prefix":"","firstName":"Veronica","middleName":"","lastName":"Noya-Padin","suffix":""},{"id":506864414,"identity":"171d2aa8-503a-4adb-ad30-f17b71266e88","order_by":1,"name":"Annabelle Mawhinney","email":"","orcid":"","institution":"University of Plymouth","correspondingAuthor":false,"prefix":"","firstName":"Annabelle","middleName":"","lastName":"Mawhinney","suffix":""},{"id":506864415,"identity":"3ea32256-3af9-4faa-bcdc-eab88c3feb70","order_by":2,"name":"Phillip Buckhurst","email":"","orcid":"","institution":"University of Plymouth","correspondingAuthor":false,"prefix":"","firstName":"Phillip","middleName":"","lastName":"Buckhurst","suffix":""},{"id":506864416,"identity":"bcebdd72-b2ee-4c51-9e6c-ec9da15108f7","order_by":3,"name":"Hugo Pena-Verdeal","email":"","orcid":"","institution":"Universidade de Santiago de Compostela","correspondingAuthor":false,"prefix":"","firstName":"Hugo","middleName":"","lastName":"Pena-Verdeal","suffix":""},{"id":506864417,"identity":"563d6d06-2931-4213-aa85-980391ebc5d4","order_by":4,"name":"Craig McNeile","email":"","orcid":"","institution":"University of Plymouth","correspondingAuthor":false,"prefix":"","firstName":"Craig","middleName":"","lastName":"McNeile","suffix":""},{"id":506864418,"identity":"8f40f01b-a58c-4b20-a440-4690646b777c","order_by":5,"name":"Stephen Hall","email":"","orcid":"","institution":"University of Plymouth","correspondingAuthor":false,"prefix":"","firstName":"Stephen","middleName":"","lastName":"Hall","suffix":""},{"id":506864419,"identity":"547a5463-fb7b-4c2f-87b0-27253041e68b","order_by":6,"name":"Hetal Buckhurst","email":"data:image/png;base64,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","orcid":"","institution":"University of Plymouth","correspondingAuthor":true,"prefix":"","firstName":"Hetal","middleName":"","lastName":"Buckhurst","suffix":""}],"badges":[],"createdAt":"2025-08-22 13:08:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7434789/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7434789/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90411201,"identity":"e2293659-64a3-4ecd-b759-9f3be38b35e9","added_by":"auto","created_at":"2025-09-02 12:20:15","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":111183,"visible":true,"origin":"","legend":"\u003cp\u003eVisual presentation of an example power curve (-3.00 D) with the locations of the power peaks and troughs highlighted for each cycle as well as the location of the central zones.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7434789/v1/4db30997edb38ebd6e9bcf6e.png"},{"id":90411044,"identity":"65556362-88b1-43e2-811a-afd8077ca7ff","added_by":"auto","created_at":"2025-09-02 12:12:15","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":840619,"visible":true,"origin":"","legend":"\u003cp\u003eAbsolute power of MYLO CLs (n=60) with varying power (–1.00 to –10.00D in 1.00D steps) and fixed combinations of TD and BOZR. Individual lines represent the labelled distance powers.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7434789/v1/afafa474552f26a2d88782a7.png"},{"id":90411042,"identity":"d9f32923-3603-4e10-8530-03a4dcd964f8","added_by":"auto","created_at":"2025-09-02 12:12:15","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":237805,"visible":true,"origin":"","legend":"\u003cp\u003eAbsolute power of MYLO CLs (n=37) with fixed power (–3.00 D) and varying combinations of TD (13.50 to 15.50 mm, in 0.50 mm steps) and BOZR (7.1 to 9.8 mm in 0.30 mm steps).\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7434789/v1/f8d3236d126d279cb7f86323.png"},{"id":90412246,"identity":"dc1218c8-a2a8-4d28-930e-26b458f25b42","added_by":"auto","created_at":"2025-09-02 12:36:15","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":70855,"visible":true,"origin":"","legend":"\u003cp\u003eLocation of the peaks and troughs relative to the optical centre of the MYLO CLs (n=91).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7434789/v1/7d54f1b70c0a907dc870ba0d.png"},{"id":90411206,"identity":"91c70d0e-7884-42bb-8be9-5d0656373023","added_by":"auto","created_at":"2025-09-02 12:20:15","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":73185,"visible":true,"origin":"","legend":"\u003cp\u003eRelative power of each Zone, trough and peak. (n=91)\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7434789/v1/a49ad5511569ab3ded068617.png"},{"id":90413257,"identity":"fc88e006-1c63-49e4-8c06-7778930221aa","added_by":"auto","created_at":"2025-09-02 12:44:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1866303,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7434789/v1/7739001a-77c4-4fc4-a211-256daadf71ed.pdf"},{"id":90411040,"identity":"ad158b0c-be9b-48c7-b4a7-0ccae81e6b11","added_by":"auto","created_at":"2025-09-02 12:12:15","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":23964,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementarytablesEDOF.docx","url":"https://assets-eu.researchsquare.com/files/rs-7434789/v1/8e9f9339be4fe1c10953597b.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Power Profiles of an extended depth of focus contact lens for Myopia Management","fulltext":[{"header":"Key points","content":"\u003col\u003e\n \u003cli\u003eThe MYLO EDOF contact lens demonstrates a consistent optical power profile, comprising alternating myopic peaks and hyperopic troughs with diminishing amplitudes toward the lens periphery.\u003c/li\u003e\n \u003cli\u003eZernike polynomial fitting enabled power estimation within the central 0.5 mm radius, revealing a rapid progression from hyperopic to myopic defocus.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eConsistent power profiles across powers and parameters confirm predictable optical performance of the lenses, however underscore the need for updated standards to evaluate non-zonal EDOF lens designs.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Introduction","content":"\u003cp\u003eTo address the rapid rise in myopia prevalence,[1] optical interventions continue to be developed.[2] Although the precise mechanisms underlying myopia progression remain unclear, evidence suggests that refractive development relies on a visual feedback process in which peripheral retinal input regulates axial growth.[3] Specifically, modulation of peripheral retinal image defocus and contrast plays a crucial role in myopia management [4]. Given their demonstrated efficacy, [5, 6] multifocal contact lenses (MFCLs) have emerged as a widely adopted strategy for myopia management.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePower profile mapping of MFCLs used for myopia management is essential for the development and clinical assessment of optical designs, as the power profile directly influences retinal image formation. MFCLs typically exhibit rotational symmetry, but their power profiles vary depending on the design.[7] Key factors characterising these profiles include the location of distance and near correction zones, the magnitude of near addition power, transition diameters, and the rate of power change. MFCLs can be broadly classified into two categories: lenses with an optical gradient profile and those with an alternating or stepped profile.[8] Optical gradient profile designs feature a progressive power variation, with relative minus or plus power increasing toward the periphery in centre-near and centre-distance lenses, respectively. In contrast, MFCLs with an alternating or stepped profile exhibit abrupt power changes either in the form of concentric rings or with a single step between the central and peripheral power.[9]\u003c/p\u003e\n\u003cp\u003eUnlike these MFCL designs, which provide discrete focal points, extended depth of focus (EDOF) lenses have a continuously changing power across their surface, fluctuating between myopic and hyperopic defocus. Consequently, there are no discrete distance and near focal points, and instead they exhibit a continuum of foci rather than distinct foci. Significant differences exist among EDOF lens designs used in myopia management. For instance, the NaturalVue®\u0026nbsp;lens (Visioneering Technologies, USA) employs a catenary curve design, where the central region corrects the refractive error, followed by a rapid peripheral power increase that induces myopic defocus.[10] In contrast, the MYLO lens (Mark’ennovy, Spain) features a non-monotonic design with no discrete power zones. Instead, its power varies above and below the normal mean in an aperiodic pattern, with gradual transitions between power changes and a relative negative power shift toward the periphery.[11]\u003c/p\u003e\n\u003cp\u003eEhrmann noted that an inherent limitation of all power mapping instruments and methods is their inability to accurately measure close to the optical centre.[12] It has been previously reported that power measurements close to the optical axis can be unstable due to the use of a 1/r weighting factor, where \u003cem\u003er\u003c/em\u003e is the radial distance from the optical centre. [13] As \u003cem\u003er\u003c/em\u003e approaches zero, this factor increases greatly, amplifying even minor measurement noise. To address this issue, investigators using the\u0026nbsp;NIMOevo®instrument have often excluded the central 0.5 mm radius from their analysis.[8, 13, 14] While this omission has minimal impact on the evaluation of concentric bifocal lenses, where the central power tends to remain stable, it poses limitations for the assessment of EDOF lenses. These designs frequently show complex power variations in the central zone — with some progressing rapidly from myopic to hyperopic defocus, and others showing the opposite trend. Capturing these central optical features is therefore essential to fully characterise EDOF lens performance. While ISO standards offer guidance on interpreting the power profiles of MFCLs,[15] they do not currently address EDOF lenses. Given the diversity in EDOF lens designs, there is no standardised method for evaluating their power profiles. As a result, the optical parameters influencing the effectiveness of these lenses for myopia management remain unclear. Despite the increasing use of MFCLs for myopia management, predicting individual outcomes remains challenging. Physiological factors such pupil size [16-18] and retinal shape [19, 20] as well as modifiable variables related to MFCL design and fit [21-24] are likely to play a significant role. Typically, contact lens (CL) fitting parameters are available only in discrete diameters and base curves, which limits optimisation of the fit on the individual eye. The MYLO MFCL addresses this limitation by offering a wide range of total diameters (TD) and back optic zone radii (BOZR). However, to the authors’ knowledge, no comprehensive studies have investigated the impact of different MFCL parameters on their optical profiles. Therefore, the objective of this study was to evaluate the power profiles of different combinations of power and fitting parameters for a specific myopia management EDOF CL (MYLO, Mark’ennovy). The study compares a semi-automated and a fully automated method for determining the locations of power changes and explores their relationship with base lens power and fitting parameters.\u003c/p\u003e"},{"header":"Methods","content":"\u003ch2\u003eContact lenses\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eThe MYLO Silicone Hydrogel EDOF CL is a CE marked soft, monthly disposable CL approved for myopia management. The CL is manufactured using a lathe process, allowing for a wide\u0026nbsp;range of parameters: TD (13.50 to 15.50 mm in 0.50 steps), BOZR (7.1 to 9.8 mm in 0.3 steps) and spherical powers (-0.25 to -15.00 D in 0.25 D steps).[25] The fitting parameters of the lenses included in the study were chosen based on two criteria:\u003c/p\u003e\n\u003ch3\u003eVarying lens power with fixed TD and BOZR parameters.\u0026nbsp;\u003c/h3\u003e\n\u003cp\u003eTo assess changes in the power profile with CL power, two fixed TDs (14.00 mm and 14.50 mm) as well as two BOZRs (8.0 mm and 8.6 mm) were selected whilst assessing the power (-1.00 to -10.00 D in 1.00 D steps). These parameters were chosen based on their common usage in myopia management and align with those observed for other myopia management MFCLs such as MiSight\u0026reg; 1 Day (8.7/14.2 mm), Bloom Day (8.3/14.5 mm), and Amiopik (8.7/14.2 mm) lenses.[26-28] Additionally, extreme parameter values (7.1/13.50 mm and 9.8/15.00 mm) were included and analysed across the same power range to evaluate consistency (Table 1).\u003c/p\u003e\n\u003ch3\u003eVarying TD and BOZR parameters with fixed lens power\u003c/h3\u003e\n\u003cp\u003eTo evaluate the impact of fitting parameters on the power profiles of the MFCLs, all commercially available combinations of BOZR and TD were assessed using a fixed power of -3.00 D. BOZR was varied in 0.3 mm increments, spanning the available range from 7.1 mm to 9.8 mm, while TD was varied in 0.5 mm increments, from 13.50 mm to 15.50 mm (Table 1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1.\u0026nbsp;\u003c/strong\u003eLens parameter configurations used in the study.\u0026nbsp;TD = Total Diameter.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eBOZR = Back Optic Zone Radii.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"576\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 148px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePower (D)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTD (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBOZR (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" style=\"width: 148px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eVarying lens power with fixed TD and BOZR parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e\u0026ndash;1.00 to \u0026ndash;10.00 in 1.00 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e13.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e7.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e\u0026ndash;1.00 to \u0026ndash;10.00 in 1.00 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e14.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e8.0, 8.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e\u0026ndash;1.00 to \u0026ndash;10.00 in 1.00 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e14.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e8.0, 8.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e\u0026ndash;1.00 to \u0026ndash;10.00 in 1.00 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e15.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e9.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" style=\"width: 148px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFixed lens power with varying TD and BOZR parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e-3.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e13.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e7.1 to 9.2 in 0.3 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e-3.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e14.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e7.4 to 9.5 in 0.3 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e-3.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e14.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e7.7 to 9.8 in 0.3 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e-3.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e15.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e8.0 to 9.8 in 0.3 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 190px;\"\u003e\n \u003cp\u003e-3.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp\u003e15.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 171px;\"\u003e\n \u003cp\u003e8.3 to 9.8 in 0.3 steps\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAs per ISO 18369-3,[29] prior to measurement, each CL was removed from its blister pack and immersed in standard phosphate-buffered saline (PBS) (n=1.334) at a temperature of 20.0\u0026deg;C (\u0026plusmn; 1.0\u0026deg;C) for at least 30 minutes.\u003c/p\u003e\n\u003ch2\u003eAssessment of contact lens thickness\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eCLs were placed within a conical glass tube filled with fresh PBS within an intraocular lens holder (Trioptics, www.trioptics.com), with the convex side facing upward and the CL edges resting on the holder. Imaging of the CLs was achieved using the Ganymede\u0026trade; GAN312 Spectral Domain Optical Coherence Tomography (SD-OCT) system with the addition of an IMM4-SP1 Z-spacer (Thorlabs, www.thorlabs.com), equipped with a 54 mm effective focal length scanning lens optimised for immersion evaluation. Axial and lateral resolution in water of the instrument is 4.5 \u0026micro;m and 12 \u0026micro;m, respectively. The image acquisition involved averaging 25 scans, with an A-scan rate of 10 kHz.[30] Optical Coherence Tomography (OCT) images were corrected for the refractive index of the CL material (MYLO, n=1.376). CT of the CL at the apex was measured on each OCT image using ImageJ (v1.54h, https://imagej.net/ij/).\u003c/p\u003e\n\u003ch2\u003ePower profile assessment\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eThe\u0026nbsp;NIMOevo\u0026reg;\u003csup\u003e\u0026nbsp;\u003c/sup\u003e(Lambda-X, www.ophthalmics.lambda-x.com) is a commercially available optical device designed for the metrology of CLs.[8] Utilizing Phase Shifting Schlieren technology, it measures wavefront aberrations using collimated light at a wavelength of 546 nm, enabling the extraction of optical power across the CL in dioptres. Specific advantages of power profile measurement with the NIMOevo\u0026reg;\u003csup\u003e\u0026nbsp;\u003c/sup\u003eover traditional Hartmann-Shack aberrometers include the higher spatial resolution offered and have been discussed extensively in previous studies.[8, 31, 32] For each measurement, the CL was immersed in PBS within the manufacturer-provided quartz cuvette and positioned over the internal CCD camera. Measurements were taken at the geometric centre of the CL with the following settings: aperture diameter of 10 mm, liquid refractive index (PBS, n=1.334), CLs refractive index (MYLO, n=1.376), the nominal lens diameter (TD of the test lens), BOZR of lens, and centre thickness as measured by the OCT system. A \u0026quot;wet to dry\u0026quot; conversion was applied. The averaged radial power profile across the 10 mm aperture (260 individual measurements per CL) was exported in CSV format. Radially averaged profile outputs exhibit symmetry about the optical centre (OC). However, as previously reported, inaccuracies arise in the vicinity of the OC due to the application of a 1/r weighting factor, where r denotes the radial distance from the OC[13]. At small radial distances, this factor increases sharply, amplifying even minimal measurement noise[33]. To address this, rather than excluding data within the central 0.5mm radius as done in other studies [13, 33, 34], the measurement process was adapted to improve the accuracy and stability of central power measurements, as described in the central zone power assessment section.\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003eCentral zone power assessment\u003c/h2\u003e\n\u003cp\u003eThis study adopted a Zernike polynomial fitting approach rather than relying on traditional radial power maps. Zernike polynomials up to 6th order were used to reconstruct the wavefront, from which spherical power was derived within precisely defined zones.\u003c/p\u003e\n\u003cp\u003eAccurate Zernike fitting depends on both the order of the polynomials and the density of data points within the analysis zone.[35] Under default settings, the\u0026nbsp;NIMOevo\u0026reg;\u003csup\u003e\u0026nbsp;\u003c/sup\u003esystem samples at a lateral resolution of 40 microns. For this study, the manufacturer modified the settings to achieve a 20-micron resolution, significantly increasing the number of points within the central region and improving the fidelity of the Zernike fit. However, this increased the time taken for each scan.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eUsing this enhanced resolution, spherical power was measured and then calculated three times for \u0026nbsp;the following aperture diameters:\u003c/p\u003e\n\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003eZone 1: Central 0.50 mm diameter (0.25 mm radius)\u003c/li\u003e\n \u003cli\u003eZone 2: Annular region from 0.50 mm to 1.00 mm diameter (0.25 - 0.50 mm radius)\u003c/li\u003e\n \u003cli\u003eZones 1 \u0026amp; 2 combined: Full 0.00 - 1.00 mm diameter (0.00 - 0.50 mm radius)\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThis method allowed for more robust and reliable assessment of central optical power, particularly in EDOF lenses where central variation is a defining feature of the design.\u003c/p\u003e\n\u003ch2\u003eData analysis\u003c/h2\u003e\n\u003cp\u003eThe average radial power profile data from the\u0026nbsp;NIMOevo\u0026reg;\u003csup\u003e\u0026nbsp;\u003c/sup\u003ewas imported into Microsoft Excel. The CL generates an aperiodic power profile which appears akin to a damped sine wave with three distinct peaks of progressively reducing positive power each followed by a trough of greater negative power. In addition, there is a general slope towards increasing negative power in the periphery (Figure 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor each lens the lateral locations and the dioptric power of the three troughs and peaks were identified by fitting spline curves to the power profile and then determining\u0026nbsp;the inflection points of these curves using MATLAB (MathWorks, USA).[36]\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSince no standardised methodology exists for assessing power profiles of EDOF lenses and determining the positions of the peaks and troughs two methods were employed. Initial analysis for both techniques required a piecewise cubic spline curve to be fitted to each power profile. The first method utilised a semi-automated process to identify the points of inflection along the cubic spline curve. Through visual inspection, an assessor then subjectively determined which of these inflection points corresponded with each peak and trough of the power profile. The second method, which was fully automated using Python, applied a smoothing function to the cubic spline curve to remove erroneous inflection points until just the six inflections were present thus removing the requirement of a subjective assessment.[37]\u003c/p\u003e\n\u003cp\u003eThe dioptric magnitude of each peak and trough and the central zones were determined and then the labelled lens power was subtracted from the value to determine relative magnitude. Descriptive statistics (mean and standard deviation) were used to express the locations of the peaks and troughs. A two-way repeated measures ANOVA was used to determine if a significant difference in the locations of the peaks and troughs existed between the two methodologies employed for determining the inflection points. Pearson\u0026rsquo;s correlation coefficient was used to assess the relationships between power zone location and peak amplitude, both calculated by semi-automated and fully automated processes, with lens power and fitting parameters (TD and BOZR).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003ePower profiles\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the power profiles for a range of lenses where the TD and BOZR were kept constant, but lens power was systematically assessed. A consistent pattern of fluctuating power, evident as three peaks and troughs, was observed for all combination of lens parameters. The magnitude of the peaks and troughs progressively reduced with increasing distance from the centre. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows power profiles of -3.00D lenses with varying TD and BOZR. Yet again a consistent pattern of power fluctuation was evident for the range of parameters assessed.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eVarying TD and BOZR parameters with fixed lens power\u003c/h3\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eComparison between semi-automated and automated methods for determining the position of the peaks and troughs\u003c/h3\u003e\n\u003cp\u003eBoth methods created equivocal results (F\u0026thinsp;=\u0026thinsp;0.116, p\u0026thinsp;=\u0026thinsp;0.733) with slightly less variance found with the fully automated process (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The position of the peaks and troughs was consistent throughout the power ranges and fitting parameters except for the first trough which exhibited double the variance of the other peaks.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eRelationship between peak/trough location, relative magnitude, lens power, and fitting parameters\u003c/h3\u003e\n\u003cp\u003eUsing the semi-automated method, weak correlations (|r| between 0.200 and 0.390) were observed between power and both the first peak (r = \u0026minus;\u0026thinsp;0.207) and the third peak (r = \u0026minus;\u0026thinsp;0.363), as well as between power and the third trough (r = \u0026minus;\u0026thinsp;0.337). In addition, the third trough showed weak correlations with BOZR; (r = \u0026minus;\u0026thinsp;0.280) and TD (r = \u0026minus;\u0026thinsp;0.214).\u003c/p\u003e\u003cp\u003eIn contrast, the fully automated method revealed that power was weakly correlated with the first peak (r = \u0026minus;\u0026thinsp;0.278), the third peak (r = \u0026minus;\u0026thinsp;0.241), and the second trough (r = \u0026minus;\u0026thinsp;0.287). Moreover, moderate correlations were found between power and both the second peak (r = \u0026minus;\u0026thinsp;0.419) and the third trough (r = \u0026minus;\u0026thinsp;0.435). No other correlations reached statistical significance (p\u0026thinsp;\u0026lt;\u0026thinsp;0.050) (Supplementary, Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eComparison between semi-automated and automated methods to determine the relative power of the peaks and troughs\u003c/p\u003e\u003cp\u003eRelative power was similar when using both semi-automated and the automated method (F\u0026thinsp;=\u0026thinsp;0.019, p\u0026thinsp;=\u0026thinsp;0.892), with less variance found with the fully automated process (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The first trough exhibited the highest level of variance of all peaks and troughs.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eUsing both the automated and semi-automated analysis methods, a significant weak correlation (|r| between 0.231 and 0.397) was observed between labelled lens power and the relative power of all the peaks and troughs with the exception of the 1st trough (r\u0026thinsp;=\u0026thinsp;0.042, p\u0026thinsp;=\u0026thinsp;0.696). A significant correlation was found between labelled lens power and the power of Zone 1 (r\u0026thinsp;=\u0026thinsp;0.280, p\u0026thinsp;=\u0026thinsp;0.007) and Zone 2 (r\u0026thinsp;=\u0026thinsp;0.212, p\u0026thinsp;=\u0026thinsp;0.044), but not Zone 1 \u0026amp; 2 combined (r\u0026thinsp;=\u0026thinsp;0.200, p\u0026thinsp;=\u0026thinsp;0.057). No other significant correlations were revealed (p\u0026thinsp;\u0026lt;\u0026thinsp;0.050) (supplementary, Table\u0026nbsp;2).\u003c/p\u003e\n\u003ch3\u003eCentral lens thickness\u003c/h3\u003e\n\u003cp\u003eAverage CT was 0.136\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 mm. No correlation was found between CT and labelled CL power (r\u0026thinsp;=\u0026thinsp;0.100, p\u0026thinsp;=\u0026thinsp;0.342).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eTo the authors\u0026rsquo; knowledge, this is the first published investigation to assess a myopia management contact lens across the widest reported range of lens powers and fitting parameters. The primary aim of this study was to evaluate the consistency of the MYLO lens design across its power range and fitting options. Detailed analysis of refractive power profiles in MFCLs provides crucial insights into how these designs alter the retinal image\u0026mdash;and their potential role in myopia management. Recent evidence suggests the importance of the location of induced retinal blur in reducing axial length progression.[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] Given its significance, it is essential to identify the region of the MFCL that provides additional plus power and assess whether it corresponds to the retinal area (6\u0026ndash;9\u0026deg;) recognised as crucial for slowing myopia progression. Since this retinal zone plays a key role in myopia management, evaluating the consistency of zone locations across the power range is important to detect potential optical variations in the MFCL that could impact its effectiveness. Within the central 3 mm radius, the CL maintains a highly consistent optical profile, demonstrating a damped sine wave pattern superimposed on an overall negative curve. The locations of the troughs and peaks, as well as the relative power of each zone, peak and trough, remained largely consistent across all evaluated CLs.\u003c/p\u003e\u003cp\u003eAs expected, the locations and powers of the peaks and troughs are independent of the BOZR. Of particular interest is that these locations and powers are also consistent regardless of the TD of the lens. This optical consistency offers both advantages and potential drawbacks. A key advantage is that practitioners can transition between different lens powers and fitting parameters without significantly altering the relative positive visual loads that contribute to myopia management. This predictability ensures that myopia management strategies remain stable regardless of modifications to lens parameters. An alternative approach could involve adjusting troughs and peak locations based on TD, shifting them outward as lens diameter increases. This would be relevant if horizontal iris diameter were strongly correlated with axial length. However, Magnetic Resonance Imaging (MRI) studies have demonstrated a weak association between anterior and posterior segment dimensions.[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] Given the challenges in predicting axial length from anterior segment parameters, maintaining a consistent optical profile across different lens diameters appears to be the preferred strategy. A uniform and predictable optical design may provide better myopia management by ensuring consistent retinal defocus regardless of lens fitting variations. Interestingly, the overall negative curve (superimposed on the damped sine wave), is indicative of negative spherical aberration, demonstrating that the MYLO MFCL incorporates an aspheric design, as evidenced by the stable level of negative spherical aberration across the power range.[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] This contrasts with the spherical MiSight\u0026reg; 1 Day CL, which exhibits increasing negative spherical aberration with higher base powers.[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] The different optical designs of these CLs are particularly relevant when considering how they influence the mechanism to slow down axial growth. The NIMOevo\u0026reg; system evaluates light travelling along the optic axis, yet myopia progression is believed to be more influenced by off-axis light. Consequently, future investigations should explore the role of asphericity in both orthogonal and oblique light paths to better understand its impact on myopia progression.\u003c/p\u003e\u003cp\u003eThe MYLO CL profile demonstrates 1.24\u0026thinsp;\u0026plusmn;\u0026thinsp;0.79 D of central hyperopic defocus within the central 0.25 mm radius, followed by 0.41\u0026thinsp;\u0026plusmn;\u0026thinsp;0.38 D of myopic defocus within the 0.25\u0026ndash;0.50 mm annulus. When assessed together, these two zones provide a result close to the labelled power (0.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.38 D). Beyond this, the lens exhibits three peaks and troughs, transitioning from central myopic defocus to progressively more hyperopic defocus toward the periphery. In addition to this progressive shift, the amplitude of the peaks and troughs decreases with increasing radial distance. This highlights an important distinction between the continuous power profile observed with such EDOF MFCLs and the stepwise power changes typical of zonal designs. The ability to analyse continuously progressing CLs without predefined zones represents a methodological strength of this study, as it enables precise characterisation of the positions of peaks and troughs and the relative power variations between them.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] This strength is further emphasised by recent studies highlighting the limitations in measuring distance zones in EDOF lenses, as their multiple power variations prevent a clear definition of these zones. This contrasts with conventional centre-near progressive lenses, where the distance zone is more clearly defined, and the evaluation models are simpler, as they only require analysing a single progressive profile rather than multiple power peaks.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eThe optical power distribution of EDOF design CLs is not accurately described in terms of addition, as this does not capture the reality of the optical profile. Addition is a change in power that remains constant in a particular area of the CL compared to another area of lower power. A myopia management CL that can be defined using this terminology is the MiSight\u0026reg; 1 Day MFCL. However, power in EDOF CLs undergoes continuous fluctuations in the form of oscillatory cycles, making it unfeasible to delineate a region of constant power. Consequently, EDOF design CLs, such as the MYLO, are defined by troughs and peaks in their power profile and are therefore better described by the relative power of troughs and peaks rather than by the concept of addition.\u003c/p\u003e\u003cp\u003eA key strength of this study lies in the use of the NIMOevo\u0026reg; system. Optical power measurements within the central optical zone (0.50 mm radius) are known to be unreliable, and Lambda-X explicitly advises against interpreting data in this region due to inherent limitations in the system\u0026rsquo;s measurement algorithm. This constraint is consistent with previous studies, which have identified similar issues in this and other devices that rely on algorithmic power calculations.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] To mitigate this limitation, the present study analysed the central region using two discrete zones, deriving optical power from Zernike polynomial fitting rather than radial power profiles. This approach revealed a notable region of hyperopic defocus within the central 0.25 mm followed by low myopic defocus. However, the application of Zernike polynomials in this context must be approached with caution. Accurate fitting requires sufficient spatial resolution\u0026mdash;specifically, an adequate number of data points across the area of interest. While the NIMOevo\u0026reg; system allows adjustment of settings to increase data point density beyond factory defaults, the polynomial fit remains a critical factor in data interpretation.\u003c/p\u003e\u003cp\u003eThe principal advantage of Zernike fitting in the central 1 mm diameter lies in its robustness against the mathematical instabilities inherent in power profile calculations at very small radii. When using the radial power maps as r approaches zero, measurement noise is amplified, often resulting in spurious spikes or oscillations. Utilising a polynomial fit models the entire 2D wavefront surface and derives local power analytically from the fitted coefficients, eliminating the singularity at r\u0026thinsp;=\u0026thinsp;0. Because the fit uses data from the entire aperture, the central estimate is constrained by a physically smooth wavefront model, reducing the influence of localised artefacts and sparse central sampling. This approach also retains the full 2D optical information, avoiding the loss of asymmetry and subtle aberration effects that occur when using a single averaged radial profile. The NIMOevo\u0026reg; system uses a 6th-order Zernike polynomial to fit surface deflections and derive power, which means fitting 28 coefficients (up to 6th order) to the data points. Given the enhanced 20\u0026micro;m resolution, even with a 0.5mm central diameter, there were sufficient data points to provide a fit resistant to noise. By combining high-density NIMOevo\u0026reg; sampling with Zernike fitting, the present study was able to obtain stable and plausible estimates of central optical power that would not have been achievable using the conventional power profile method alone. However, a 6th-order Zernike polynomial may be insufficient to fully capture the complex wavefronts produced by multifocal or EDOF CL.[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e] To reduce potential fitting errors, this study limited the analysis to well-defined, narrow zones rather than attempting a global fit across the entire optic. This methodological choice enhances the reliability of the results by minimising distortions introduced by underfitting complex optical surfaces.\u003c/p\u003e\u003cp\u003eBodas-Romero et al. proposed four metrics for describing the power profile of a multifocal/EDOF CL. [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e] However, three of these metrics required normalising the radial power profile to 0 D at the geometric centre\u0026mdash;a problematic approach given the known unreliability of NIMOevo\u0026reg; measurements in this region. As a result, only their maximum addition point (MAD, equivalent to our first peak location) was independent of the central reference, yet no analysis was presented to determine whether MAD varies with labelled power. Furthermore, the absence of any curve fitting or smoothing means that all metrics based on a single maximum value were vulnerable to noise spikes, making their repeatability questionable. In contrast, our methodology avoids these pitfalls by combining high-density sampling (20 \u0026micro;m) with Zernike polynomial reconstruction of the 2-D wavefront and piecewise spline fitting of the radial profile. This removes the 1/r instability at small radii, constrains the central estimate using information from the entire aperture, and smooths out point-wise noise artefacts that could otherwise distort parameters such as addition magnitude or location. Importantly, our proposed metrics are not dependent on the central lens power. Consequently, our derived metrics, including the equivalent of MAD, are robust to local measurement artefacts and provide a more reliable representation of the true optical design.\u003c/p\u003e\u003cp\u003eIt is worth noting that the position and relative power of the first trough exhibited greater variance compared to other peaks, suggesting that this measurement may be affected by central-region limitations. Despite these constraints, both the semi-automated and fully automated methods employed in this study produced comparable results, with the automated approach demonstrating slightly lower variance.\u003c/p\u003e\u003cp\u003eFinally, this study highlights a gap in existing ISO standards for MFCLs, aligning with previous reports.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] Current guidelines do not account for continuously progressing lens designs such as the MYLO, which lack discrete optical zones. Standardisation of power profile analysis methods for these CLs would be beneficial for both research and clinical applications, ensuring more accurate characterisation of their optical properties.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe MYLO CL exhibits a highly consistent optical design across its power range and fitting parameters, indicating that changes in lens power or parameters do not impact its optical performance. The findings of this study provide valuable insights into the lens\u0026rsquo; optical properties and suggest that a stable, predictable power profile may be advantageous in maintaining consistent myopia management outcomes. Future research should focus on evaluating off-axis light distribution and refining methodologies for characterising non-zonal MCFLs to further optimise myopia management strategies.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eDisclosure\u003c/h2\u003e\u003cp\u003eThe authors report no conflicts of interest and have no proprietary interest in any of the materials mentioned in this article.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eV.N-P., A.M., and H.P-V. collected data. V.N-P. and C.M. analysed data. V.N-P., A.M., P.B., H.P-V., S.H. and H.B. contributed to writing the manuscript and preparing figures. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. University of Plymouth PhD fee waiver for Annabelle Mawhinney.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHolden, B.A., et al., \u003cem\u003eGlobal Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050\u003c/em\u003e. Ophthalmology, 2016. 123(5): p. 1036\u0026ndash;42.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJonas, J.B., et al., \u003cem\u003eIMI Prevention of Myopia and Its Progression\u003c/em\u003e. Investigative Ophthalmology \u0026amp; Visual Science, 2021. 62(5).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTroilo, D., et al., \u003cem\u003eIMI - Report on Experimental Models of Emmetropization and Myopia\u003c/em\u003e. Investigative Ophthalmology \u0026amp; Visual Science, 2019. 60(3): p. M31-M88.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMarcos, S., \u003cem\u003eOptical and Visual Diet in Myopia\u003c/em\u003e. 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Ritchey, and D.A. Berntsen, \u003cem\u003ePower Profiles of Centre-Distance Multifocal Soft Contact Lenses\u003c/em\u003e. Ophthalmic Physiol Opt, 2021. 41(2): p. 393\u0026ndash;400.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eISO, \u003cem\u003eOphthalmic Optics - Contact Lenses \u0026ndash;\u0026thinsp;6838.\u003c/em\u003e Tolerances and methods for measurement of multifocal contact lens addition power, 2024.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMontes-Mico, R., et al., \u003cem\u003eIn Vitro Power Profiles of Multifocal Simultaneous Vision Contact Lenses\u003c/em\u003e. Cont Lens Anterior Eye, 2014. 37(3): p. 162\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen, Z., et al., \u003cem\u003eImpact of pupil diameter on axial growth in orthokeratology\u003c/em\u003e. Optom Vis Sci, 2012. 89(11): p. 1636\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTan, Q., et al., \u003cem\u003eRetinal image quality in myopic children undergoing orthokeratology alone or combined with 0.01% atropine\u003c/em\u003e. Eye Vis (Lond), 2023. 10(1): p. 21.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePope, J.M., et al., \u003cem\u003eThree-dimensional MRI study of the relationship between eye dimensions, retinal shape and myopia\u003c/em\u003e. Biomed Opt Express, 2017. 8(5): p. 2386\u0026ndash;2395.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi, Q. and F. Fang, \u003cem\u003eContribution of the retinal contour to the peripheral optics of human eye\u003c/em\u003e. Vision Res, 2022. 198: p. 108055.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRizzo, G.C., et al., \u003cem\u003eCentration assessment of an extended depth of focus contact lens for myopic progression control\u003c/em\u003e. Cont Lens Anterior Eye, 2023. 46(1): p. 101533.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCorpus, G., A. Molina-Martin, and D.P. Pinero, \u003cem\u003eEfficacy of Soft Contact Lenses for Myopia Control: A Systematic Review\u003c/em\u003e. Semin Ophthalmol, 2024. 39(3): p. 185\u0026ndash;192.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSong, D., et al., \u003cem\u003eEfficacy and adverse reactions of peripheral add multifocal soft contact lenses in childhood myopia: a meta-analysis\u003c/em\u003e. BMC Ophthalmol, 2024. 24(1): p. 173.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRuiz-Pomeda, A. and C. Villa-Collar, \u003cem\u003eSlowing the Progression of Myopia in Children with the MiSight Contact Lens: A Narrative Review of the Evidence\u003c/em\u003e. Ophthalmol Ther, 2020. 9(4): p. 783\u0026ndash;795.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNoya-Padin, V., et al., \u003cem\u003eDehydration and physicochemical changes in myopia control contact lenses: influence of material and maintenance solutions\u003c/em\u003e. Cont Lens Anterior Eye, 2025: p. 102478.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRuiz-Pomeda, A., et al., \u003cem\u003eMiSight Assessment Study Spain (MASS). A 2-year randomized clinical trial\u003c/em\u003e. Graefes Arch Clin Exp Ophthalmol, 2018. 256(5): p. 1011\u0026ndash;1021.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePaun\u0026eacute;, J., et al., \u003cem\u003eChanges in Peripheral Refraction, Higher-Order Aberrations, and Accommodative Lag With a Radial Refractive Gradient Contact Lens in Young Myopes\u003c/em\u003e. Eye Contact Lens, 2016. 42(6): p. 380\u0026ndash;387.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWalline, J.J., et al., \u003cem\u003eA Randomized Trial of Soft Multifocal Contact Lenses for Myopia Control: Baseline Data and Methods\u003c/em\u003e. Optom Vis Sci, 2017. 94(9): p. 856\u0026ndash;866.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eISO, \u003cem\u003eOphthalmic Optics - Contact Lenses \u0026ndash;\u0026thinsp;18369\u003c/em\u003e in \u003cem\u003ePart 3: Measurment Methods\u003c/em\u003e. 2017.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDavidson, B.R. and J.K. Barton, \u003cem\u003eApplication of optical coherence tomography to automated contact lens metrology\u003c/em\u003e. J Biomed Opt, 2010. 15(1): p. 016009.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDominguez-Vicent, A., et al., \u003cem\u003eRepeatability of in vitro power profile measurements for multifocal contact lenses\u003c/em\u003e. Cont Lens Anterior Eye, 2015. 38(3): p. 168\u0026ndash;72.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMons\u0026aacute;lvez-Rom\u0026iacute;n, D., et al., \u003cem\u003ePower profiles in multifocal contact lenses with variable multifocal zone\u003c/em\u003e. Clin Exp Optom, 2018. 101(1): p. 57\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEhrmann, K., \u003cem\u003ePros and Cons of soft contact lens power mapping\u003c/em\u003e. Optometry \u0026amp; Contact lenses, 2024. 4(1): p. 28\u0026ndash;34.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMawhinney, A.J., et al., \u003cem\u003eCharacterizing power profiles of a concentric ring multifocal contact lens for myopia management: a novel approach\u003c/em\u003e. Cont Lens Anterior Eye, 2025: p. 102454.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSmolek, M.K. and S.D. Klyce, \u003cem\u003eGoodness-of-prediction of Zernike polynomial fitting to corneal surfaces\u003c/em\u003e. J Cataract Refract Surg, 2005. 31(12): p. 2350\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLaw, E.M., et al., \u003cem\u003ePredicting the Postoperative Addition Power of a Multifocal Intraocular Lens at the Spectacle Plane\u003c/em\u003e. J Refract Surg, 2021. 37(5): p. 318\u0026ndash;323.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVirtanen, P., et al., \u003cem\u003eSciPy 1.0: fundamental algorithms for scientific computing in Python\u003c/em\u003e. Nature Methods, 2020. 17(3): p. 261\u0026ndash;272.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSwiatczak, B., H.P.N. Scholl, and F. Schaeffel, \u003cem\u003eRetinal \u0026ldquo;sweet spot\u0026rdquo; for myopia treatment\u003c/em\u003e. Scientific Reports, 2024. 14(1): p. 26773.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKneepkens, S.C.M., et al., \u003cem\u003eEye Size and Shape in Relation to Refractive Error in Children: A Magnetic Resonance Imaging Study\u003c/em\u003e. Investigative Ophthalmology \u0026amp; Visual Science, 2023. 64(15): p. 41\u0026ndash;41.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKoh, S., et al., \u003cem\u003eEfficacy of spherical aberration correction based on contact lens power\u003c/em\u003e. Cont Lens Anterior Eye, 2014. 37(4): p. 273\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBodas-Romero, J., L. Batres, and G. Carracedo, \u003cem\u003ePower Profiles of Different Myopia Control Soft Contact Lenses\u003c/em\u003e. Eye Contact Lens, 2025. 51(6): p. 261\u0026ndash;268.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDel \u0026Aacute;guila-Carrasco, A.J., E. Papadatou, and P.J. Buckhurst, \u003cem\u003eMeasuring aberrations of multifocal and extended depth-of-focus intraocular lenses\u003c/em\u003e. J Cataract Refract Surg, 2019. 45(10): p. 1516\u0026ndash;1517.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBodas-Romero, J., L. Batres, and G. Carracedo, \u003cem\u003ePower Profiles of Different Myopia Control Soft Contact Lenses\u003c/em\u003e. Eye \u0026amp; Contact Lens, 2025. 51(6): p. 261\u0026ndash;268.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"ophthalmic-and-physiological-optics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Ophthalmic and Physiological Optics](https://link.springer.com/journal/44402)","snPcode":"44402","submissionUrl":"https://submission.springernature.com/new-submission/44402/3?","title":"Ophthalmic and Physiological Optics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Extended Depth of Focus (EDOF), power profiles, myopia, myopia management, contact lenses","lastPublishedDoi":"10.21203/rs.3.rs-7434789/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7434789/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose: \u003c/strong\u003eTo characterise the optical power profiles of an extended depth of focus (EDOF) contact lens (MYLO, Mark’ennovy) for myopia management across its full range of labelled powers and fitting parameters.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003ePower profiles of 91 MYLO lenses were measured using the NIMOevo®\u003csup\u003e \u003c/sup\u003einstrument. Lenses ranged in labelled power from –1.00 to –10.00 D, total diameters (TD) from 13.50 to 15.50 mm and back optic zone radii (BOZR) from 7.1 to 9.8 mm. Central thickness (CT) was assessed using spectral-domain optical coherence tomography. Lens power profiles were fitted with piecewise cubic splines, and peaks and troughs were identified using both semi- and fully automated inflection point detection. Zernike polynomial fitting, applied at enhanced resolution, was used to derive power within the central 0.50 mm radius.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e All lenses demonstrated a damped sine-wave power profile, featuring three consistent peaks and troughs superimposed on a general trend toward peripheral minus power. The location and relative magnitude of these features remained highly consistent across all combinations of lens power, TD, and BOZR. Central zone analysis revealed a mean relative hyperopic defocus of 1.24 ± 0.79 D within the central 0.25 mm radius, followed by a myopic shift of 0.41 ± 0.38 D in the 0.25 - 0.50 mm annulus, resulting in a near-emmetropic outcome (0.08 ± 0.38 D) across the full central 0.00 - 0.50 mm region. CT was not correlated with labelled power.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e The MYLO lens demonstrates a stable and predictable optical profile across a broad range of fitting parameters, indicating that changes in lens power or parameter do not impact its optical performance. The study highlights the need for refined standards in the evaluation of power profiles of EDOF CLs.\u003c/p\u003e","manuscriptTitle":"Power Profiles of an extended depth of focus contact lens for Myopia Management","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-02 12:12:11","doi":"10.21203/rs.3.rs-7434789/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2025-08-25T17:50:32+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-25T17:47:52+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-24T22:53:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"Ophthalmic and Physiological Optics","date":"2025-08-22T12:53:15+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"ophthalmic-and-physiological-optics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Ophthalmic and Physiological Optics](https://link.springer.com/journal/44402)","snPcode":"44402","submissionUrl":"https://submission.springernature.com/new-submission/44402/3?","title":"Ophthalmic and Physiological Optics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"98e576bc-af13-4894-9c5e-20bb1779eab5","owner":[],"postedDate":"September 2nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-13T02:08:18+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-02 12:12:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7434789","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7434789","identity":"rs-7434789","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}