What is Myopia?
Myopia, or “nearsightedness” is a refractive error of the eye that causes light to be focused in front of the retina, causing distance images to be blurry and near objects to be clear.
What Causes Myopia?
Myopia can be due to the eye being too long, too high focusing power of the cornea, or changes to the natural lens inside of the eye. As children grow, their eyes naturally elongate. However, in children who develop myopia, their eyes elongate too much. This growing process generally begins around age 7 and can continue up until age 25. While there is no way to reverse myopia, there are several methods to slow the progression as your child grows. These methods are known as “Myopia Control”. The sooner myopia control is started, the more effective it is.
Why Control Myopia Development?
High myopia is not just a vision problem, but a health issue. Higher degrees of myopia are associated with higher risk of glaucoma, cataracts, and retinal detachment. Additionally, glasses for higher myopia are significantly thicker and heavier, and contacts often are limited in higher powers. Refractive surgery, such as LASIK and PRK, may not be an option in higher myopia.
Methods of Myopia Control:
Contact Lenses
Contact Lenses
Corneal Refractive Therapy (CRT)
Corneal Refractive Therapy (CRT) is the most common and recommended for myopia control in children. CRT is a FDA-approved, non-surgical overnight contact lens therapy that corrects your child’s prescription while they sleep. During the daytime, your child will see clearly without glasses or contacts.
Longitudinal studies have proven the safety and effectiveness of this treatment, and it received unanimous FDA approval in 2002 without age restriction. Multiple studies have shown a 50-60% reduction of myopia progression in children wearing CRT lenses1,2. Corneal Refractive Therapy (CRT) involves specialty contact lens considerations and instrumentation. Therefore, only certified doctors are licensed to prescribe it. At Silicon Valley Eyecare, all of our optometrists are certified CRT eye care professionals.
Read more about CRT lenses here.
Multifocal Contact Lenses
Myopia progression has been shown to reduce myopia progression up to 60% in children wearing multifocal contact lenses compared to single vision contact lenses3. This is currently an active area of ongoing research.
Pharmaceutical Eyedrops
Eyedrops such as atropine work to relax the focusing muscle inside the eye and cause dilation. New research has shown that low-dose atropine slows the progression of nearsightedness with minimal side effects4.
Glasses
Bifocals or Progressives
This option provides some myopia reduction, but is not considered a strong option5.
Undercorrection
Undercorrecting the nearsighted prescription was previously thought to improve eyesight, but strong studies now show that not only does undercorrection not slow progression, but may in fact even increase myopia progression in children6.
Environment
According to major studies done in California7, Singapore8, and Australia9, increasing amount of time spent outdoors in sunlight is correlated to less eye growth and less progression of nearsightedness. Studies are still being conducted regarding the mechanism behind this theory. It is recommended to spend at least 12 hours per week outdoors (about 2 hours/day). It is important for everyone, children included, to wear sunglasses when in direct sunlight to reduce damage from harmful UV light.
References:
1. Walline JJ et al, “Corneal Reshaping and Yearly Observation of Nearsightedness.” British Journal of Ophthalmology 2008 June.
2. Cho et al. “Longitudinal Orthokeratology Research in Children.” Current Eye Research 2005 Jan; 30(1) : 71-80.
3. Chamberlain P et al. Clinical evaluation of a dual-focus myopia control 1 day soft contact lens- 2 year results. Presented at: American Academy of Optometry meeting; Anaheim, CA: Nov 8-13, 2016.
4. Gong Q et al. Efficacy and Adverse Effects of Atropine in Childhood Myopia: A Meta-Analysis. JAMA Opthalmol. 2017 Jun 1; 135(6): 624-630.
5. Gwiazda J et al. “A Randomized Clinical Trial of Progressive Addition Lenses versus Single Vision Lenses on the Progression of Myopia in Children.” Invest Ophthalmology Vision Science. 2003; 44: 1492-1500.
6. Adler D and Millodot M. “The possible effect of undercorrection on myopic progression in children.” Clinical Experimental Ophthalmology. 2006; 89:5: 315-321.
7. Zadnik K et al. “Initial cross-section results from the Orinda Longitudinal Study of Myopia.” Optometry Vision Science 1993 Sept; 70 (9): 750-758.
8. Saw SM et al. “A Cohort Study of Incident Myopia in Singaporean Children.” Invest v. 2006; 47: 1839-1844.
9. Rose KA et al. “Outdoor Activity Reduces the Prevalence of Myopia in Children.” Ophthalmology. 2008; 115: 1279-1285.
