What is Myopia?
Myopia (nearsightedness) is a common vision condition where the eyeball is too long or too powerful, resulting in blurred far vision. Vision for close objects is clear within a certain range.
Why are we concerned about myopia?
The prevalence of myopia in young people is increasing at an alarming rate worldwide, bringing with it a host of health risks. In North America, the prevalence of myopia has increased from 28.3% in 2000 to 42.1% in 2020. A recent study predicts that 50% of the world population will be myopic by the year 2050. Generally once you become myopic, it tends to worsen over time. Higher levels of myopia are associated with higher risks of eye diseases like glaucoma, retinal detachment and cataract later in life.
| -1.00 to -3.00 D | -3.25 to -5.00 D | -5.25 to -7.00 D | Over -7.00 | |
|---|---|---|---|---|
| Myopic Maculopathy | 2 X | 10 X | 41 X | 127 X |
| Retinal Detachment | 3 X | 9 X | 22 X | 44 X |
| Cataract (PSC) | 2 X | 3 X | 6 X | Data not available |
| Glaucoma | 2 X | 3 X | 3 X | Data not available |
| Table 1: Increased risk of myopia comorbidities with increasing degree of myopia | ||||
What causes myopia development and progression?
There are many factors that affect the development and progression of myopia. Some of the main risk factors are:
- Genetics
- If one parent has myopia, their child has approximately 20% chance of also developing myopia.
- If both parents have myopia, the probability of their child developing myopia more than doubles.
- Age of Onset
- More likely to progress faster and reach higher myopia when onset <9 year of age.
- Binocular vision disorders (i.e. esophoria, accommodative lag, high AC/A, etc)
- Limited time outdoors
- Less than 2 hours outdoors per day significantly increases the likelihood of developing myopia.
- Excessive near work
- More than 2 hours per day on near work (not including school work).
