It is predicted that by 2050, the number of people with myopia will double worldwide to 5 billion, with 1 billion of those with high myopia (defined as -6.00D or greater). The World Health Organization (WHO) has now even recognized this as a “myopia epidemic”.
Health Problems
Myopia is not just a visual concern but is also linked to an increased risk for other ocular conditions, many of which can lead to irreversible blindness. For each diopter of myopia there is an increase in the following:
- 58% for myopic maculopathy
- 30% for retinal detachment
- 21% for posterior subcapsular cataracts
- 20% for open angle glaucoma
Myopia Risk Factors
- Age of Onset
- Parental myopia
- Amount of myopia
- Visual environment
Age of Onset of Myopia
Age is by far the most significant factor in determining how myopic the child will become. Children who are myopic at age 6 or 7 can progress twice as quickly than those who first develop myopia at age 11.
Parental Myopia
Family history is not only a high-risk factor for myopia development but also myopia progression. Children with two myopic parents are significantly more likely to become myopic compared to those with one or zero myopic parents. If both parents have high myopia (≥-6.00D), there is a high risk their child will also become a high myope.
Amount of Myopia
The likelihood of developing high myopia is significantly higher in those starting with a higher amount of myopia at baseline.
Visual Environment
There has been exploration on the role of the amount of near work or time spent outside and myopia progression. Studies show that outdoor time can be linked to slowing myopia progression in children. It has been shown that it is not the screen time itself that increases the risk of myopia progression but more so the home confinement and decreased outdoor exposure.
The Goal of Myopia Management
Refractive Error
Without myopia control treatment, depending on their age, a child's refractive error can progress anywhere between -0.50 D and -1.00 D a year. With treatment that progression can decrease to only -0.25 D a year.
Axial Length
Children who do not need visual correction typically progress at ~0.1mm per year, while young myopia children tend to have a progression of 0.3mm per year. The goal of myopia control treatment is to keep the axial length change to 0.1mm ro less and below 26mm since anything above that can increase the risk of certain ocular conditions.
