In the absence of effective interventions, the global prevalence of myopia is projected to reach 50% by the year 2050 (Holden et al, 2016). A concomitant increase in the prevalence of high myopia will likely lead to a rise in consequent conditions that threaten sight. This has stimulated interest in methods that slow myopia progression. Treatment approaches in the United States include low-dose atropine, daytime multifocal and dual-focus contact lens wear, and overnight orthokeratology.
Nevertheless, opinions vary regarding contact lenses for myopia management. Some practitioners may assert that not offering therapies is considered unethical. Other practitioners may believe that an increased risk of potentially serious infections is an argument to not prescribe contact lenses to children. Here I’ll discuss the risks and benefits of prescribing soft lenses for myopia management.
The complications associated with soft lens wear are well documented. Corneal infiltrative events (CIEs) include infiltrative keratitis, contact lens-associated red eye, and contact lens peripheral ulcers. These are not sight-threatening and are managed by discontinuation of lens wear, with a possible addition of a topical prophylactic medication. Infiltrative events occur at rates between 300 to 400 per 10,000 patient years in adults. In patients 8-to-12 years of age, the rate of infiltrative keratitis is 97 per 10,000 patient years. The rate increases to 335 per 10,000 patient years for ages 13-to-17 years (Chalmers et al, 2011).
Sight-threatening microbial keratitis (MK) is less common. In daytime soft lens wear, the incidence is two-to-four cases for every 10,000 patient years in adults (Stapleton et al, 2008; Dart et al, 2008). In children, the frequencies of MK were 0 cases for every 10,000 patient years in patients 8-to-12 years old and 15 cases for every 10,000 patient years in ages 13-to-17 years (Chalmers et al, 2011).
With respect to soft contact lens wear for myopia management, three important variables influence the risk of CIEs and MK: storage, lens material, and patient age. The risk of moderate and severe MK in daily wear lens users was increased 6.4 times by poor storage case hygiene and 5.4 times by infrequent storage case replacement (Stapleton et al, 2012). This risk can be decreased by effective education on being compliant with cleaning and disinfecting both the lenses and storage cases and discarding lenses and cases on the scheduled replacement period. Of course, if the prescription allows, prescribing a daily disposable lens also further decreases the risk of corneal complications.
In summary, the frequency of CIEs and MK in children 12 years or younger is no higher than what is observed in adults and may even be lower. This is important because it is the typical age group for which myopia management with contact lens therapy is initiated. The increase in infiltrative events in older children and teenagers is probably influenced by less parental involvement regarding lens care and handling.
The reasons to slow myopia progression are numerous (Bullimore and Brennan, 2019). They include better uncorrected and corrected visual acuity that, in turn, improves visual quality and reduces dependence on spectacle lenses. Additionally, lower myopic refractive errors are ideal for later refractive surgery procedures, with resulting better outcomes in comparison to higher myopic prescriptions. The greatest benefit of reducing myopia, however, is a resulting decreased risk of complications that are associated with visual impairment such as retinal detachment, myopic maculopathy, glaucoma, and cataracts.
More Benefit Than Risk
Myopia is becoming more common and is starting at younger ages. Without intervention, sight-threatening complications from high myopia will become more common. The societal burden for these events will be enormous and greatly outweighs the modest and largely manageable risks of pediatric contact lens wear. CLS
For references, please visit www.clspectrum.com/references and click on document #311.