Over the past few decades, we have seen enormous increases in technology in the areas of contact lens materials, design, and wearing modalities. There have been changes in the affordability and access of contact lenses around the world.
New research and regulatory approvals in the critical area of myopia control have the potential to further expand the reach of contact lenses to an increasingly younger and broader audience. However, questions remain about ways to improve contact lens safety, particularly with respect to contact lens-related microbial keratitis.
The first annual American Academy of Optometry Think Tank brought together several researchers and key opinion leaders from around the world to address this topic at the 2019 American Academy of Optometry Annual Meeting.
Meaning
The infection rate associated with contact lenses has not changed in several decades. Additionally, there is a trend toward more severe infections associated with Acanthamoeba and fungi. The increasing use of contact lenses in children demands our attention with surveillance and case-control studies.
Purpose
The American Academy of Optometry (AAO) brought together researchers and key opinion leaders from around the world to discuss contact lens-associated microbial keratitis at the 2019 AAO Annual Meeting.
Methods
Experts presented in four sessions.
Session 1 covered the epidemiology of microbial keratitis, the pathogenesis of Pseudomonas aeruginosa, and the role of lens care systems and storage cases in corneal disease.
Session 2 covered non-bacterial forms of keratitis in contact lens wearers.
Session 3 covered future needs, challenges, and research questions regarding microbial keratitis in youth and myopia management, the microbiome, antimicrobial surfaces, and genetic susceptibility.
Session 4 covered communication and compliance imperatives.
Results
The absolute rate of microbial keratitis has remained very constant for three decades despite new technologies, and long-term use significantly increases the risk.
The improved oxygen delivery provided by silicone hydrogel lenses has not affected rates and, although the introduction of daily disposable lenses has minimized the risk of severe disease, there is no consistent evidence that they have altered the overall rate of microbial keratitis.
Orthokeratology lenses at night may increase the risk of microbial keratitis, especially secondary to Acanthamoeba, in children. Compliance remains a concern and a significant risk factor for disease. New insights into the host microbiome and genetic susceptibility may reveal new theories.
More studies are needed, such as appropriate case-control designs for rare diseases and registries.
Summary and unanswered questions for the entire expert group
Case-control studies are needed to answer many of the questions raised in this Think Tank. Most importantly, the group felt that we need them early, especially in children, to guide us in controlling myopia. However, the problem is not simply determining likelihood ratios for the risk of infection. It is also necessary to have a better understanding of absolute risk, no matter how difficult it may be to achieve.
Additionally, data on the effectiveness of long-term myopia control with orthokeratology or myopia control with soft multifocal contact lenses are crucial because parents should be aware of the potential benefit before taking the risk. The group suggested creating a registry database. For example, a central data collection site for populations fitted with nocturnal orthokeratology or soft multifocal lenses would allow industry, the Food and Drug Administration, and researchers to look back and assess risk.
There are examples in other medical specialties, such as psychiatry, where the entire industry has committed to making all of its clinical data available in a database so that any researcher can use it to test hypotheses or look at mechanisms. A registry or database is something that should be encouraged as a profession, especially with questions about the safety of contact lenses for myopia control in children.
The group also discussed compliance campaigns, explicitly targeting direct-to-consumer campaigns, as the Centers for Disease Control and Prevention is doing. Social media platforms can be tailored to target audiences working with health communicators and graphic artists. The message should be vetted by researchers to ensure it is evidence-based and tested on contact lens wearers to ensure it is meaningful.
Additionally, collaborative work between the Centers for Disease Control and Prevention Youth Contact Lens Evaluation Study teams found that the behaviors of contact lens wearers who purchased contact lenses directly from their optometrist’s office were no different from those of contact lens wearers. which he bought on the Internet. This should encourage practitioners to emphasize retraining and education about contact lens risk at each follow-up visit.
In conclusion, collectively, Think Tank participants agreed that complacency should not hold us back. We shouldn’t just accept the status quo . We should not subscribe to the mentality that if we can’t fix it easily, we will simply recognize the infection rate and eventually lose track.
We understand that the risk of microbial keratitis, nighttime use, and Acanthamoeba keratitis has not decreased for decades, despite innovation. For these reasons, the profession, federal agencies, and industry must move forward in funding studies to resolve these issues. We need to push harder against the barriers to change.
Final message
The first annual AAO Think Tank recognized that the risk of microbial keratitis has not decreased for decades, despite innovation. Important questions and research directions remain.
