Reconfiguring treatment goals for paediatric myopia around ocular development

Childhood myopia has lifelong implications, from vision loss to other ocular disease. Paediatric myopia control methods are vital to global ocular health. In order to discern the best possible therapeutic intervention for an individual, the patient’s age should be taken into account, both for continuation of care and for establishing a measurable treatment goal. For the purposes of controlling myopia among children ages 6 to 18, physicians should measure axial length (AL) growth rates in comparison with physiological AL growth rates, suggested Professor Hakan Kaymak, MD.

Prof Kaymak is the medical director of Breyer, Kaymak & Klabe Augenchirurgie’s retina centre in Düsseldorf-Oberkassel, and a professor of experimental ophthalmology at the Saarland University Hospital, Homburg/Saar, Germany. Prof Kaymak presented on age-matched treatment protocols for myopia control at the Winterthur Ophthalmology Symposium¹ in Winterthur, Switzerland, on 15 March 2024. In November 2023, Prof Kaymak and colleagues in Germany, Hong Kong and the Netherlands authored a paper on age-matched analysis of AL growth as measured in a patient population treated with defocus incorporated multiple segments (DIMS) spectacle lenses.²

In his lecture, Prof Kaymak recommended an approach to myopia treatment which considers the physiological hallmarks of ocular development that are unique to those developmental stages. An age-matched myopia control (AMMC) system would require new classifications of myopia and emmetropia based on axial length and refraction in cyclopegia as a function of age.¹ Between studies, the definition of myopia can vary greatly, as can the standards of severity for myopia progression and AL growth. Prof Kaymak indicated that a lack of standardised criteria makes it difficult to evaluate treatment efficacy, and also called for updated inclusion criteria for studies, based on participants’ biometric data, age and gender.

Over time, the portfolio of myopia-inhibiting therapies has expanded. Paediatric patients are a notable segment of the patient base with myopia: childhood myopia has lifelong implications for overall ocular health.

Appropriate myopia progression interventions should take into consideration both the patient’s age-based abilities/lifestyle and the disease progression. Prof Kaymak posits that because AL growth rate changes over time, decreasing with age, AL measurements should be compared with an age-matched cohort of children with emmetropic eyes.

Annual AL growth data

The AMMC system is defined as a system “in which the actual annual AL growth rate of a patient is classified against the average physiological AL growth rate of an age-matched cohort of children who become or remain emmetropic.”²

To demonstrate proposed categorisations of myopia progression, Prof Kaymak shared a graph which plotted patients’ annual AL growth rate (in mm/year) alongside age, then divided those groups into three “zones.” (Figure 1)

The green zone comprised patients whose AL growth rates were consistent with physiological development considered normal for the age group. The authors² established this physiological growth rate with a +25% boundary to account for possible measurement fluctuations. Patients who experienced moderately excessive AL growth, at a rate +25% to +50% above the age-appropriate physiological growth, fell into the yellow zone.

Figures courtesy of Prof Hakan Kaymak, MD.

Patients with high AL growth (more than +50% the age-matched AL growth rate) were categorised in the red zone. Notably, patients under 13 years of age could be categorised into any of the zones, but the criteria for inclusion in the yellow zone excluded that group.

The reasoning, the authors explained, is that after a patient reached 13 years of age, the AL growth rate was set at 0.10 mm/year to reflect “the degree of agreement in repeated AL measurements with currently available biometers.”²

When evaluating therapeutic performance, Prof Kaymak said, an age-matched physiological AL growth cohort can have distinct advantages over comparing results with those of an untreated control group. In a survey of eight myopia control studies, Prof Kaymak plotted patients’ ages and annual AL growth rates against the AMMC chart. The resulting comparison provided a standard metric for treatment efficacy among varied myopia control methods, age groups and stages of myopia progression. (Figure 2)

Under the AMMC model, Prof Kaymak recommended therapeutic interventions for any patients in the yellow zone, and strongly recommended therapy for patients in the red zone of AL growth. Younger children may already be in treatment for myopia, but older children and teenagers should also be considered for age-appropriate therapeutic interventions to combat high AL growth rates. Prof Kaymak directed practitioners to the Myopia Solutions site, a free, web-based tool, which allows users to evaluate AL growth in accordance with the AMMC system.

Matching therapeutics to patients

With a framework in place for measuring therapeutic performance, Prof Kaymak concluded by recommending a treatment progression for paediatric myopia. As a first-line therapy, Prof Kaymak suggested DIMS spectacle lenses. Prior research findings have indicated that DIMS spectacle lenses are a safe and efficacious myopia control method for paediatric patients,³ and that the lenses can work in conjunction with other therapies^3,4 to control myopia progression. With these considerations in mind, Prof Kaymak recommended that, in the case of a therapeutic gap following 1 year of DIMS spectacle lens use, patients could use the lenses in conjunction with 0.05% atropine drops.

Following adoption of these therapeutics, older patients could expand their treatment options based on lifestyle needs. For older children and teenagers with a desire for spectacle independence, he recommended multifocal contact lenses with a high addition for continued limitation of myopia progression.⁵ Prof Kaymak suggested that patients with a desire for spectacle freedom would be appropriate candidates for orthokeratology contact lenses.

References

1. Kaymak H. Myopia control in children: what is the treatment goal? Lecture presented at: Winterthur Ophthalmology Symposium; March 15, 2024; Winterthur, Switzerland.

2. Graff B, Lam CSY, Vlasak N, Kaymak H. Age-matched analysis of axial length growth in myopic children wearing defocus incorporated multiple segments spectacle lenses. Br J Ophthalmol. Published online November 27, 2023. doi:10.1136/bjo-2023-324508

3. Zhang W, Tan X. Effects of orthokeratology lens compared to defocus incorporated multiple segments lens for adolescent myopia and factors related to corneal injury. Altern Ther Health Med. Published online March 1, 2024.

4. Jethani J. Effect of defocus incorporated multiple segments lenses on halting myopia progression not responding to low-concentration atropine (0.01%) eye drops. Indian J Ophthalmol. Published online February 23, 2024. doi:10.4103/IJO.IJO_2378_23

5. Walline JJ, Walker MK, Mutti DO, et al. Effect of high add power, medium add power, or single-vision contact lenses on myopia progression in children: the BLINK randomized clinical trial. JAMA. 2020;324(6):571-580. doi:10.1001/jama.2020.10834

Hakan Kaymak, MD | E: dr.h.kaymak@gmail.com

Kaymak is the medical director of Breyer, Kaymak & Klabe Augenchirurgie’s retina centre in Düsseldorf-Oberkassel. He is a professor of experimental ophthalmology at the Saarland University Hospital, Homburg/Saar, and also teaches at the University of Appplied Sciences Jena, both in Germany. He is a consultant for Hoya and Haag-Streit.