What is short-sightedness and how does it affect vision?

If someone is myopic or nearsighted, close objects appear sharp and well-defined, but objects at a distance appear blurred. As such, nearsightedness may not affect someone’s ability to read a book or look at a computer screen, but it makes it difficult to watch a film, read a whiteboard in a classroom, or to see clearly when driving.^{3, 4} While these symptoms can be easily managed with prescription glasses or contact lenses, undiagnosed nearsightedness can sometimes cause eye strain and headaches, or squints in children.

What are the treatment options for cataracts?

More severe cases of short-sightedness are categorised as high myopia. Conventionally, an eye is considered to have high myopia if it requires -6.0 dioptres (lens strength) or more to correct vision. About 10% of people with nearsightedness will have high myopia, which places them at an increased risk of developing eye conditions such as glaucoma and cataracts.^{1, 2}

What causes short-sightedness?

Nearsightedness occurs because the cornea (the clear part at the front of the eye) is too curved or the eyeball itself is too long. Both of these scenarios mean that instead of focusing the image on the retina (the light-sensitive layer in the eye), the lens forms the image in front of the retina. This is what makes distant objects appear distorted and blurred.^3,4

Although the exact cause of nearsightedness is still unclear, researchers have identified some key risk factors. One of these factors is genetics, as myopia tends to run in families, with children being three times more likely to develop myopia if one parent is short-sighted, and seven times more likely to be myopic if both parents have the condition.

However, myopia can also occur in adults due to visual stress or medical conditions such as diabetes. Alongside this, environmental factors also play a role in myopia development. If you spend considerable time indoors staring at screens, reading, or doing other work that requires intense close vision, your risk of myopia may be higher.⁴

What are cataracts and how do they impact vision?

A cataract is a clouding of the lens in the eye. The lens is the structure that focuses light onto the retina to form images. In healthy eyes, the lens is transparent, however, people with cataracts will see cloudy or blurry patches in their vision (like looking at objects through a dirty or fogged-up windshield).⁵

The most common cause of cataracts is ageing. By the age of 60 to 65, most people have at least some degree of lens opacity. However, other eye conditions such as myopia and medical conditions like diabetes can also cause cataracts to develop. Some inherited genetic disorders have also been found to increase your risk of cataracts.

Although bothersome, cataracts can be easily treated. Cataract surgery is the only effective treatment to remove cataracts, with the majority of people who undergo it reporting improved vision afterwards.⁶ It involves removing the clouded lens and replacing it with an artificial one. You can learn more about cataract surgery here.

What is the link between nearsightedness and cataracts?

While treating myopia is usually as simple as wearing prescription glasses or lenses for most people, research has found a link between high myopia and the development of cataracts.⁷ In particular, one study found that cataracts are more likely in people who began using distance glasses before the age of 20, as well as in people above the age of 55 who develop nearsightedness.^{7, 8}

While the precise link between high myopia and cataracts is not completely clear, it is believed that severely myopic eyes have reduced levels of protective antioxidants, which could make them more prone to developing cataracts.⁷

What are the first signs of cataracts?

Most cataracts develop slowly and don't disturb your eyesight early on, but there are a few symptoms you can look out for. Before cloudy vision develops, cataracts patients can experience difficulty with night vision, colours appearing faded, and seeing haloes around lights. As the cataract grows in size, it can impact vision on a day-to-day basis, making it difficult to read, watch TV, drive, or perform other activities of daily living.⁵