The eye is one of the most remarkable and most fragile organs in the body, and through this year, it has been under more severe strain than usual. “It is designed for distance vision,” says Dr Mahipal Sachdeva, president of the All India Ophthalmological Society. “So, having to look at computer screen at close quarters for a long time and staying indoors naturally tends to have a negative impact.”
If your screen is brighter than your surroundings, your eyes have to work harder to see, Kierstan Boyd, director of patient education at the American Academy of Ophthalmology, wrote in a report titled Computers, Digital Devices and Eye Strain, released in March. Amid lowered outdoor activity and less screen-free recreation, adults and children alike are also reporting a higher incidence of dry eye caused by this excessive strain.
This has been an especially hard year for children’s eyes. At a young, developing stage, they have found themselves exposed to long hours of online learning, often on tablets and cellphones held close to the eye. Unable to spend leisure time outdoors, these hours have become linked to screens more than before too. “Around the world there has been a rise in the incidence of myopia,” says Dr Sachdeva.
Another condition to watch out for is what is known as computer vision syndrome or CVS. “If you are experiencing more headaches or itchiness in the eyes, it is likely that the cause is excessive strain to the eye as a result of looking at screens too long,” Dr Sachdeva says. “The smaller and brighter the screen, the more the strain on the eyes.”
Here’s why. People have a blink rate of about 20 times per minute. “When you read from a screen, you are concentrating on the screen, reducing the blink rate to half, and thereby reducing the tear lubrication that a blink provides to the outer layer,” says Dr Sachdeva. “As you read line by line, the eye is constantly moving, causing further strain.”
While reading hard copy reduces the blink rate to almost similar levels, the difference is the number of incomplete blinks. When reading on a brightly lit screen, even the blinks that do occur are only partial. The upper eyelid doesn’t meet the lower eyelid and hence does not form a continuous tear film over the eye’s surface. Studies suggest that there are more incomplete blinks during screen time than when reading off a duller surface like paper.
To help your eyes cope with the strain better, keep your devices at least 25 inches from your face, and position the screen in such a way that your gaze is downward rather than straight, as that helps somewhat to reduce the strain on the eye muscles.
It also helps to stick to some variation of the 20-20-20 rule. The rule states that, ideally, you should give your eyes a 20-second rest every 20 minutes by looking at an object 20 feet away. If you can’t manage a break every 20 minutes, try one every half hour or at least every hour.