Myopia Literature Review
Follow the links below to read other summaries in this series:
Myopia Interventions: Effective But Unpredictable
Myopia is a growing epidemic, and optometrists are increasingly expected to mitigate it rather than just correct it. As the research is vast and more than any single OD could realistically follow, experts at the Brien Holden Vision Institute recently published a series of literature reviews (think DEWS II, but for myopia) to help clinicians better understand the disease, current research efforts and management options. Review of Optometry selected three key papers to summarize; all nine are available here.
The onset of myopia is a trying time for a child, as adaptation to corrective lens wear doesn’t come easy. Even more insidious are eye health risks that often go unnoticed. Luckily, many therapy options exist to stave off progression—but how do you know which one is right for any given patient? The key to choosing the approprite treatment is having a firm grasp of myopia itself.
The “Clinical Management Guidelines Report,” published in a special issue of the IOVS journal, begins with a brief look at the epidemiology and risk factors. “Myopia has been traditionally viewed as a consequence of interplay between genetic, ethnic, and environmental risk factors,” the report says—all of which clinicians must keep in mind when managing patients and their parents. This means reviewing refractive error and eye growth; age; family history and ethnicity; visual environment; educational activities; and binocular vision.
Clinicians must also consider the premyope, the report says. “The child at risk of developing myopia can be identified by comparing their refractive error to the age-normal,” the authors write. “Recommending an increase in time spent outdoors is the key evidence-based strategy that appears effective in reducing the incidence of myopia across numerous studies.”
Patient Education Pearls
A significant portion of the report is aimed at preparing the clinician to discuss myopia and its risk factors with both the patient and their parents. The key here is using lay terminology, according to the authors. In addition, written lay education is important to further support the in-office discussions and provides a reference moving forward.
A significant portion of a clinician’s patient education goals is helping the patient and parents understand the treatment options, such as orthokeratology (OK), atropine and multifocal soft contact lenses. The report includes examples of parent- and patient-appropriate explanations of each intervention. OK lenses, for example, “are rigid gas permeable contact lenses worn overnight to reduce nearsightedness by temporarily and reversibly reshaping the cornea (front surface of the eye).”
The report then switches gears and focuses on the exam itself, providing a helpful seven-step procedure:
- History taking
- Best-corrected visual acuity
- Binocular vision and accommodative tests
- Anterior eye health evaluation using a slit-lamp and intraocular pressure measurement.
- Corneal topography (if indicated)
- Axial length
Each step includes tips to ensure clinicians gather all the information pertinent to the patient’s management strategy. For refraction, “the recommended dosage for cycloplegic refraction is two drops of 1% tropicamide or cyclopentolate given five minutes apart. Cycloplegic refraction should be performed 30 to 45 minutes after the first drop is instilled,” the authors suggest.
When selecting the proper treatment strategy, “an understanding or estimation of the rate at which myopia progresses for a given individual may help identify an appropriate strategy to control the rate of progression,” the report says. Although research shows myopia will progress at a faster rate in patients of a younger age, who have higher baseline myopia and have already experienced myopia progression, clinicians can also use average population-based progression rates to help steer treatment.
Other patient-specific factors such as baseline refractive error will determine the best treatment, too. Patients with astigmatism often do well in multifocal designs, although certain multifocal contact lenses have restricted power ranges, and “practitioners must consider the impact of the residual astigmatic refractive error on visual acuity, as uncorrected refractive astigmatism over 0.75DC can lead to visual compromise,” according to the report.
Clinical Care Pearls
Once the patient and practitioner are on the management journey together, ongoing clinical care is a must. The report includes guidelines to help the clinician provide appropriate advice, such as proper wearing times, balancing indoor and outdoor activities and even nutritional advice.
Contact lenses and atropine both come with possible side effects and risks of complications, and clinicians must prepare patients properly to avoid them, the report says. The authors provide a bullet-point list of action items for minimizing risk with these treatment options. For atropine, “where available, unit dose atropine preparations are preferable,” the report says. “In a multiuse bottle, to avoid contamination, never touch the tip of the bottle to the eye or any other surface and do not use the bottle past the expiration date.”
Clinicians should also provide backup spectacle correction and discuss the follow-up schedule carefully to ensure compliance. If, on follow-up (usually every six months, the report recommends) the patient’s myopia continues to progress, it’s time to consider changing therapy tactics. The report reviews the dos and don’ts of therapy modification, as well as what to expect with long-term efficacy and the possibility of rebound effects.
The authors conclude the report with a brief look at the future research directions that might impact the clinical management of myopia, including updates to OK and multifocal lens designs, and novel therapies such as scleral reinforcement. “The coming years are likely to result in a number of studies on various methods to control myopia, including novel medications, novel spectacle and contact and OK designs, as well as combination treatments,” the authors write.
|Gifford KL, Richdale K, Kang P, et al. Clinical management guidelines report. Invest Ophthalmol Vis Sci. 2019;60:M184–M203.|