Choosing Among Methods of Myopia Control

The topic of myopia control has gained increased attention among clinicians over the past few years. Educating patients about myopia control options is now considered a standard of care due to the vision-threating conditions, economic burden, and public health concerns associated with myopia. The literature suggests that there are several effective modalities to prevent the onset of myopia and slow down its progression. This article provides information regarding current management strategies for myopia control and suggests ways to select the best approach for each patient.

PREVENTION OF MYOPIA ONSET

Time Outdoors and Atropine

There are two approaches for management of myopia control. One approach is to reduce patients’ risk of developing myopia. Given that the prevalence of myopia can be as high as 84% in some Asian countries,¹ finding ways to prevent the onset of myopia is important. Although little is known about this approach, researchers have explored the importance of time outdoors and the use of low-dose atropine.

A meta-analysis by Xiong et al concluded that increasing time outdoors reduced the onset of myopia but had no influence on slowing down myopia progression in myopic children.² Less research has been conducted regarding the use of low-dose atropine in prevention of myopia onset. Fang et al showed a reduction in onset of myopia in premyopic children using atropine.^3,4 The Atropine in the Treatment of Myopia (ATOM) Study Group is currently conducting an interventional clinical study to determine the role of atropine 0.01% in preventing the onset and progression of myopia in premyopes and low myopes.⁵

REDUCTION OF MYOPIA PROGRESSION

Contact Lenses and Atropine

A second approach to myopia control is to attempt to slow the progression of myopia. Current treatments that have been shown to clinically reduce myopia progression include orthokeratology, soft center-distance multifocal contact lenses, and low-dose atropine.^6-13

The mechanisms of orthokeratology and use of soft multifocal contact lenses are attributed to optically decreasing the peripheral hyperopic defocus or increasing peripheral myopic blur.¹⁴ Multifocal lenses are commercially available in center-distance and center-near optical designs. Most studies have investigated center-distance multifocal lenses, as this optical design provides an increase in peripheral myopic defocus.¹⁵ A 2015 review by Walline showed that use of soft multifocal contact lenses and orthokeratology slowed myopia progression by 46% and 43%, respectively.¹⁶

RISK FACTORS

The patient and his or her guardian should always be made aware of the possible side effects and the clinical safety profiles of myopia control options. Although there is always a risk of microbial keratitis with contact lens wear, research suggests that children aged 8 to 14 years are less likely to develop adverse events compared with individuals aged 15 to 25 years.¹⁶ The estimated risk of microbial keratitis for soft multifocal contact lenses is about four per 10,000 wearers, for orthokeratology, about 20 cases per 10,000 wearers.¹⁷ Given that multifocal contact lenses have been linked with increased exophoria at near compared with single-vision contact lenses, clinicians should be mindful of multifocal contact lens use in children with large exophorias.¹⁸

Atropine is a nonspecific antimuscarinic eye drop often used in eye care to dilate or reduce accommodation. Its exact mechanism in myopia control is unknown.¹⁴ The effect of atropine in reduction of myopia progression is concentration-dependent. The ATOM Study found that a concentration of 0.01% had the best therapeutic index. However, initial data from the Low-Concentration Atropine for Myopia Progression (LAMP) study has shown that, of the three concentrations used (0.05%, 0.025%, and 0.01%), 0.05% was the most effective in controlling myopia progression.¹⁹ Atropine 0.01% also had a good safety profile in the ATOM 2 study, with minimal effects on pupil dilation (0.8 mm) and reduction of accommodative amplitude (2–3 D reduction).¹²

The long-term safety profile of low-dose atropine has not been established, but 1% atropine has a well-established safety profile for amblyopia treatment in children.²⁰ Overall, atropine has been shown to be an effective mechanism for myopia control, and its use for this purpose should be examined by clinicians.

TREATMENT CONSIDERATIONS

The ideal myopia control patient is a young person first being diagnosed with myopia, as these individuals have the potential to progress more than older patients and can therefore benefit the most from myopia control.²¹ However, even if a patient is outside the ideal selection criteria, myopia control can be offered to any progressive myopes, provided that it is clearly communicated that they do not fit the typical profile in myopia control clinical studies.

Given that all three treatments—orthokeratology, multifocal contact lenses, and low-dose atropine—have relatively equal efficacy,^22,23 treatment can be recommended based on the patient’s age, lifestyle, and refractive error. Atropine is best for young patients, as the child’s guardian can administer one drop of atropine in each eye at bedtime. Contact lenses are a good option for more mature children with good motivation. Orthokeratology generally requires less maturity than soft multifocal contact lenses, as the orthokeratology lenses are worn only at home with the supervision of the guardian. Soft contact lenses require the child to be able to successfully manage the contact lenses during school hours.

Generally, atropine can be used initially for young patients. As the child matures, a transition to contact lenses may be a better myopia control option, with consideration for the child’s involvement in sports or concern with appearance in glasses.²⁵

Dual therapy, combing atropine and contact lenses, can also be an option for concerned parents or if meaningful progression is detected after monotherapy has been tried.²⁶

PATIENT MANAGEMENT IN MYOPIA CONTROL

Once a treatment is selected, it is recommended to have the patient and guardian sign a consent form because all of the treatment options are off-label. Recommended safety measures include VA at distance and near, cover test at distance and near, accommodative amplitudes, pupil size, and anterior segment exam. Myopia management measurements should include axial length and refraction. Topography is recommended for treatment with multifocal lenses and is essential for orthokeratology. Patients should be monitored every 6 months to track refractive error and axial length. Additional follow-ups and testing may be indicated, depending on the selected contact lens modality.

NEW STANDARDS OF CARE

The increase in myopia prevalence has led to the development of new standards of care. Young, premyopic children should be advised to increase their time spent outdoors. Myopic children with an interest in myopia control should be advised to use either atropine, multifocal contact lenses, or orthokeratology. Patient education is an essential element of myopia management. Details should be discussed with the patient or guardian before the start of treatment.