The invention of the printing press brought great focus for the need for corrective vision. Today devices are used more than books for near vision. Humans spend a large part of their waking time staring at digital screens—computers, tablets, TV’s, smartphones and other devices. Studies have shown that children begin zooming in on digital media devices such as their parents’ tablets or smart phones as young as 6 months. By teen age years they spend as much as 7 hours a day using screened-based media, watching TV, playing video games, and social media. This is only the fun part because there is additional time spent using screens in school and homework.
The process of seeing is extremely complicated. The ray of light enters the eye through the pupil and passes through a lens. The lens works much like a microscope or looking glass curving the light beam so it can focus on the back of the eye. The lens is flexible and tiny muscles pull or push the lens to a curve that that guides the light beam. Much like moving the looking glass up and down to see the object clearly.
Gazing at the same distance for an extended time can cause the eye’s focusing system to spasm or temporarily “lock up”. This “lock up” condition is called accommodation spasm and causes the vision to blur when you look away from the screen. There has been an increase in the number of children diagnosed with myopia (near sightedness) and it is thought there may be a relationship with excessive use of these tiny muscles and the developing lens.
Parents can help healthy vision with encouraging a healthy diet, at bedtime no devices in their rooms, and helping with changing some habits while visualizing up close. One suggestion is when using a device it is important to take frequent breaks maybe ten minutes every hour. Another recommendation is to look away from the screen every twenty minutes and look at an object 20 feet away or out the window for at least 20 seconds. It has been suggested that a timer can be used to signal a break and there is software that can turn off the screen at regular intervals.
Screen position is also important. The screen should be slightly below eye level. Some recommendations for positioning is a 1/2/20 rule: mobile phones held ideally at one foot, desktop devices at 2 feet, and roughly 10 feet for TV’s (depending on the size of the TV).
Regular vision testing is strongly recommended. If a problem is found during one of these screening exams there may be a referral to an ophthalmologist. Treatment may be recommended for the prevention of more problematic myopia including glasses, specialized multifocal contact lens, and specialized drops. There is also a type of contact lens worn at night to help flatten the cornea. These treatments should be managed carefully by a specialist in children’s vision.
Visual health is important for a lifetime
by Sally Robinson, MD Clinical Professor
Keeping Kids Healthy
Published 04/2025