Increasing levels of myopia impose a health, economic, and social burden, especially in East and Southeast Asia, where the prevalence of myopia in young adults is approximately 80–90 %, and that of high myopia is 10–20 %.1,2 A recent study in Spanish children aged five to seven years reported a myopia prevalence of 19 % between 2016 and 2021, with projections indicating an increase to 30.2 % by 2030.3 During the early stage of human life, axial length (AL) is considered to be driven by emmetropisation—a physiological process—from hyperopia to emmetropia. Children who develop myopia show excessive AL elongation, which tends to stabilise after the age of 15, although it continues to increase in the top 50th percentile.4-6

Presently, there are several options to delay myopia rather than simply correcting vision and improving the quality of life.7-10 These include changes in lifestyle, such as improving time spent outdoors,11 spectacle-based strategies,12-14 pharmacological treatments,15-17 low-level red-light therapy, overnight orthokeratology with rigid gas permeable (RGP) contact lenses (CL),18 and soft CL designed for myopia management.19-24 Moreover, combining strategies such as pharmacological and optical treatments improves treatment efficacy.25-27 Regarding soft CL, previous studies showed different power profiles, including multifocal with aspherical designs (MCL) for presbyopia,23,24 extended depth of focus (EDOF),20,22,28-30 multi-concentric with annular rings,19,21,31 non-coaxial toroidal,32 and also an asymmetrical power map.33 MCL present a central optic zone with distance correction surrounded by progressively positive power to generate a positive spherical aberration, which could prevent axial elongation.24,34-36 Interestingly, a recent study suggests no evidence of a loss of treatment effect after discontinuing centre-distance soft MCL with +2.50D addition in older teenagers.37 Previous studies used MCL designs with standard parameters,23,24 so little is known about MCL with customised parameters (different base curves and diameters) in myopia control, which could be helpful in cases where adaptation is unsatisfactory. The purpose of the current study was to evaluate the myopia progression rate in Caucasian children over a two-year follow-up—as assessed by changes in AL and cycloplegic refraction from baseline—using customised progressive MCL with an addition of +2.50 D compared to single-vision distance spectacles, and to determine possible differences between groups.

Table 1 presents the baseline demographic data of the 40 participants assigned to the spectacles and MCL groups. There were no statistically significant differences in age, AL, or SE between groups. Most children (95 %) had at least one myopic parent in the MCL group; this percentage was lower (75 %) in the spectacles group. In the MCL group, there were six cases of mild corneal staining, which did not necessitate discontinuation of CL wear. No more adverse events were detected. There were no dropouts during the study period. Questionnaire responses after one month and two years of CL wear are represented in Fig. 2. All items showed a mean rating value ≥ 9. A statistically significant improvement was found in “near clarity of vision” at two years compared with one-month values.

Fig. 2.

Subjective responses after two years of contact lens wear. Results are shown as mean ± SD (error bars).

The AL and SE results at each visit are represented in Table 2. There were no differences in AL and SE progression with respect to right/left eyes, sex, or number of myopic parents, nor with the combined effect of these variables (p > 0.05).

Repeated measures ANOVA (p < 0.001) and Bonferroni post hoc test indicates statistically significant differences in AL and SE changes between all measured times for both the MCL and spectacles groups. Over the two-year follow-up, significantly less axial elongation was observed in the MCL group than in the spectacles group (p < 0.001), as represented in Fig. 3. The total increase in AL was 0.66 ± 0.03 mm (from 0.60 to 0.77) in the spectacles group (p < 0.001) and 0.51 ± 0.02 mm (from 0.40 to 0.55) in the MCL group (p < 0.001), resulting in a CARE value of 0.15 mm. Similar to AL, changes in SE were significantly different between the MCL and spectacles groups (p < 0.001) at all measured times, being smaller in the MCL group. The total increase in SE was −1.12 ± 0.14 D (from −1.00 to −1.50 D) in the spectacles group (p < 0.001) and −0.82 ± 0.25 D (from −0.50 to −1.25 D) in the MCL group (p < 0.001). SE variations between the two groups exhibited a mean difference of –0.30 D.

Fig. 3.

Mean change in axial length (A) and spherical equivalent (B) in the spectacles and contact lens groups for the two-year study period. ∗∗∗P < 0.001.

Fig. 4 illustrates the distribution of AL and SE changes during the entire follow-up period. In the spectacles group, 97.5 % of the children presented an AL increase ranging from 0.61 to 0.70 mm. In the MCL group, no elongation exceeded 0.60 mm, with 67.5 % of eyes presenting an increase between 0.51 and 0.60 mm. Regarding SE, in the spectacles group, 70 % of eyes had an SE increase of −1.00 D; in contrast, over half of the MCL group presented lower SE progression, from 0.50 to 0.75 D.

Fig. 4.

Distribution of changes in axial length (A) and spherical equivalent (B) in the spectacles and contact lens groups during the two-year study period.

There were no correlations between baseline AL and AL changes over time (p = 0.07 and p = 0.36 for the spectacles and MCL groups, respectively) nor between baseline SE and SE changes (p = 0.94 and p = 0.06 for the spectacles and MCL groups, respectively). When the relationship between changes in AL and SE for the entire period was analysed, a correlation was only found for the MCL group (rho=0.51/p = 0.01). Therefore, the greater the AL change, the larger the SE change after a two-year follow-up.

Binocular logMAR CDVA results at baseline, 12, and 24 months are represented in Table 3. There was no statistically significant change throughout the follow-up period. For CDVA, there was a statistically but not clinically significant difference lower than two letters at baseline and 24 months (p<0.05).

This study adds clinical data to the evidence indicating that the myopia progression rate can be slowed down using MCL with a + 2.50 D progressive addition compared with control single-distance vision spectacles in a Caucasian child population. In agreement with the study of Walline et al.,24 there was a low percentage of adverse events that did not lead to wear discontinuation, confirming the safety of the fitted MCL.24

The present study included Caucasian children; thus, a slower change in AL and SE than that observed in an Asian population was expected.38 On the other hand, the current study only included children with evidence of at least a −0.75 D increase over the previous year before the inclusion. Aller et al.23 studied bifocal soft CL (Acuvue bifocal, Vistakon) in multiracial children who progressed −0.50 D or more since their last examination, apart from near-point esophoria and/or accommodative dysfunctions. They reported an AL increase of only 0.05 mm after a one-year follow-up. In contrast, the control group, fitted with single-vision (SV)-CL, increased 0.24 mm, with a CARE value of 0.19 mm, higher than the current study (0.15 mm). The fitted CL presented a central optic zone <2 mm surrounded by two concentric addition rings with the maximum relative positive power.39 Walline et al.24 fitted two progressive centre distance MCL (Biofinity, CooperVision) with different additions (+2.50 and +1.50 D) and a refraction range of −0.75 to −4.00 D in 98 multiracial, mostly Caucasian, children aged 7 to 11 years. They reported a lower AL change than the present study with the +2.50 D Add (0.16 and 0.30 mm at 12 and 24 months, respectively), while the AL change was high in the +1.50 D Add group (0.26 and 0.44 mm at 12 and 24 months, respectively). The lower efficacy of Saphir Rx lens could be due to Biofinity presenting the maximum relative positive power at approximately 2 mm from the optical zone centre.

Interestingly, the efficacy in the studies of Aller et al.23 and Walline et al.,24 with smaller optic zones than the current study, could indicate that myopia control with MCL could be related both to high addition power and a more central location, similar to how a smaller back optic zone diameter in orthokeratology may be beneficial for retarding axial elongation.40

The cumulative variation in AL in the test group of the current study (0.51 mm) aligns with the paper published by Sankaridurg et al.,20 although conducted in an Asian population aged 7 to 13 years and including a spherical refractive error ranging from −0.75 to −3.50 D The authors fitted four hydrogel test CL, where test Lenses I and II had +2.50 and +1.50 D Add, respectively. Like Saphir Rx, the lenses presented the maximum relative positive power at approximately 3 mm. In addition, a stepped, relative positive power was incorporated centrally (up to 1.0 mm semi-chord) of up to +1.00 D. Comparing the results of lens I and the current study, the authors reported a slightly lower change in the same 2-year follow-up period (0.44 mm). Similar AL changes were found with test Lens II (0.45 mm).

Comparing the results of the present study with those previously obtained by the same authors with an EDOF CL (MYLO; mark´ennovy), also with a two-year follow-up and the same inclusion criteria, the efficacy of the analysed MCL was half that obtained with EDOF CL, with a CARE of 0.1 mm and 0.2 mm, respectively, at the two-year follow-up.22 On the other hand, in accordance with the current study, Ruiz-Pomeda et al.41 also conducted a study in Spanish children, mainly Caucasian, aged 8 to 12 years, ranging from −0.75 to −3.50 D, and fitted with Dual-focus CL (MiSight, CooperVision) vs Single-Vision spectacles. They found a CARE of 0.17 mm after a two-year follow-up. The authors did not have inclusion criteria of a minimum −0.75 D increase in the previous 12 months.

Regarding SE, the variation in the whole follow-up period (−0.82D) was lower than that reported by Sankaridurg et al.,20 with a mean increase of −0.92D. Theoretically, AL variation should correlate with the change in SE. However, various factors can influence the relationship between both variables. Ulaganathan et al.42 described that the mean amplitude of daily variations in AL is 0.029 ± 0.007 mm; thus, minor variations could be neglected when considering yearly AL changes. To minimise this influence, children were evaluated at the same time in the current study.

Concerning visual performance, in agreement with this study, Aller et al. found an HCVA of −0.04 logMAR with +2.50 D Add with no statistically significant difference compared to SV-CL. The satisfactory results in the subjective questionnaire were similar between one month and two years of MCL wear, agreeing with the previous ratings reported with soft CL. In a recent systematic review and meta-analysis, Ping et al.43 reported that subjective impression ratings for vision and comfort with myopia MCL were slightly lower than for single-vision lenses. Moreover, children rated their overall visual experience higher than young adults. Notably, all the subjects of the present study wished to continue wearing contact lenses.

The present study had some limitations that could be improved upon in future studies. First, the lack of randomisation is a limitation that could introduce unwanted confounding variables and bias. It is believed that this study is more representative of a real-life scenario where patient motivation plays an important role in myopia management and may result in a lower number of discontinuations from the control group (no dropout was found). However, masking was not possible, and it could inflate the perceived effectiveness of the intervention compared to real-world settings. Moreover, it would be necessary to increase the sample size. Additionally, visual function under photopic and mesopic conditions, as well as the influence of customised contact lens parameters regarding centration and movement, could be analysed, since previous studies with MCL used standard parameters.

In Caucasian children, a slower myopia progression rate was achieved with a centre distance multifocal contact lens fitting with +2.50 D addition after two years of wear compared with the single-vision distance spectacles group.

This clinical trial was conducted in accordance with the tenets of the Declaration of Helsinki and was approved by the institutional review board of the Hospital Clínico San Carlos of Madrid (Code: 19/264/E). The children’s parents/carers signed the informed consent form, and all children assented to participate in the trial.

mark´ennovy manufactured and provided the contact lenses used in the study. Avizor provided the maintenance solutions.

Sergio Díaz-Gómez: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing – original draft, Writing – review & editing. Amaia Urkia-Solorzano: Data curation, Investigation, Writing – review & editing. José A. López-Garrido: Data curation, Investigation, Writing – review & editing. Mercedes Burgos-Martínez: Conceptualization, Writing – review & editing. Jesús Carballo-Álvarez: Conceptualization, Data curation, Investigation, Methodology, Supervision, Validation, Writing – original draft, Writing – review & editing.