There is no doubt that Covid has impacted us in so many ways over the past couple of years. This includes increasing the use of screen time amongst our children and reducing the amount of time they have been able to spend outside, for example in play areas1. Children have also been required to complete home schooling delivered online via computer screens for extended periods.
Many schools and families encourage the use of screens for education, through online learning platforms or apps, and for recreation. Many children use them both at school and at home for short, regulated periods. Research suggests that too much unregulated close-up screen time can increase the risk of our children developing, or contribute to the progression of, myopia.
The information below is intended to equip you with some guidance and knowledge so that we can reduce the risk of eye problems in our children.
What is myopia?
Also referred to as short sightedness, this is a very common condition in which your eyes are naturally focused for near vision in their relaxed state. This means that close objects appear clearly in focus, but objects in the distance are blurred.
Myopia occurs when the axial length of the eye becomes too long, or the cornea becomes too curved, so that light coming in through the lens of the eye is focused incorrectly in front of the retina, rather than on it. This sends incorrect light signals to the brain, which are then interpreted as a blurred image. Typically, the longer the axial length of the eye, the higher the degree of myopia a patient will likely have.
How myopic a person is can be measured using dioptres (D), essentially this is how much lens correction is required in order to focus the image correctly on the retina. Those of you who have myopia will be able to see this measurement on your glasses prescription. Myopia can be graded as mild, moderate or severe. A score above -6.00D is considered severe or high myopia.
Why worry about myopia?
The global prevalence of myopia is increasing, with half of the population predicted to have myopia within the next 30 years2.
Although it is important to remember that most people with myopia will not develop any other eye problems, in a minority with more severe myopia, there is an increase in the development of other serious eye problems. These include retinal detachment, open angle glaucoma, macular degeneration and cataracts.
The increase in people with myopia inevitably increases the pressure on the health care system.
When does myopia start?
Myopia starts in childhood around the age of six years old, and classically worsens in adolescence. You are more likely to develop myopia if one or other of your parents is myopic. Evidence suggests that too much close-up screen time and reduced outdoor exposure to light can impact on the development and progression of myopia3.
In patients with normal vision the axial length of the eye stops growing on average at the age of 15. In patients with myopia, the axial length continues to grow, sometimes for up to 25 years3. The cornea, another factor in the development of myopia, undergoes the biggest changes within the first two years of life3.
Importantly, the earlier in childhood that myopia develops, the worse the myopia is likely to become3.
How is myopia diagnosed?
If you are concerned about your child having myopia, then the first course of action is to book an appointment with your local optician.
How is myopia treated?
In most cases myopia is treated with glasses or contact lens correction of vision. In progressive childhood myopia, topical medication may be considered. Some adults may consider surgery or laser correction of their vision.
Significantly, in childhood, research has shown that lifestyle factors such as outdoor exposure can inhibit the onset and slow progression of myopia3.
How can I reduce the risk of my child developing myopia?
The recommendations are3:
- Children aged 2-5 should have no more than one hour per day of screen time
- Children aged over five up to age 12 should have a maximum of two hours screen time per day
- Divide the total screen time into 20-minute sessions and encourage gazing into the distance for at least 20 seconds after each session
- Encourage at least 2 hours of play outdoors daily – SWAP SCREEN TIME FOR GREEN TIME!
- Any close up work should be undertaken at a distance of at least 30 cm
Mr Steven Naylor MBChB (Hons), PG Cert (Dis) Surgical Science, FRCOphth, CertLRS
References
- Progression of Myopia in School-Aged Children After COVID-19 Home Confinement. Wang et al. JAMA Ophthalmol. 2021;139(3):293-300.
- Myopia Control 2020: Where are we and where are we heading? Bullimore et al. Ophthalmic Physiol Opt 2020;40:254-270
- Myopia Management in the Netherlands. Klaver et al. Ophthalmic Physiol Opt 2020 Mar; 40 (2):230-240