What is myopia (short-sightedness)?

Medically reviewed by Christine Cancar on 11th April 2022

Myopia is a one of the most common refractive errors, causing nearby objects to appear clear and objects in the distance to appear blurry. For example, you may find it easy to focus on close work such as reading a book but have difficulty seeing road signs in the distance. It happens when the shape of your eye causes light rays to bend incorrectly. When this happens, light is focused behind the retina rather than on it.

Myopia (short-sightedness or near-sightedness) has become increasingly prevalent in recent years. The cause of myopia is not entirely clear. Some eye doctors believe it’s due to our increased use of computers, tablets and smart phone devices. They also believe that extended tasks requiring near vision can cause myopia in addition to there being genetic predispositions for myopia.

An eye exam can detect myopia and once confirmed, it can be corrected with glasses, contact lenses or eye surgery.

What are the symptoms of myopia?

You’ll have difficulty reading road signs and seeing distant objects clearly. However, you'll be able to see well for close-up tasks such as reading and computer use. Other symptoms of myopia include:

• Blurred vision when focusing on objects far away
• Squinting to see clearly
• Eye strain resulting in headaches
• Eye fatigue after tasks that require concentration
• Difficulty seeing while driving, especially at night (night myopia)

It’s crucial to ensure that you have regular eye exams (at least once every two years), but if you experience any of these symptoms, then you will need to see your optician/eye care professional sooner. They could signify another underlying eye condition, although mostly, it’s a sign that you may need a new prescription for glasses or contact lenses.

Myopia is usually detected during childhood. Symptoms of myopia in children include:

• A persistent squint
• Excessive blinking
• The need to sit close to the TV or at the front of the classroom to read the board
• A lack of awareness of objects in the distance
• Rubbing eyes frequently
• Headaches
• Holding books, tablets or doing homework too close

When to see your eye care practitioner?

You should see your eye care practitioner if your distance vision is so poor that it's interfering with everyday tasks. They will be able to determine how severe your near-sightedness is and advise on a form of vision correction.

Retinal detachment can be a complication of high myopia (anything above -5.00 dioptres). High myopia is a more severe form of this condition and occurs when the eyeball grows more than it’s supposed to, becoming very long. The below symptoms are a medical emergency and you should seek immediate medical help should you experience any of them:

• The sudden appearance of eye floaters (tiny specks that appear to drift through your field of vision)
• Flashes of light in one eye or both
• A curtain-like shadow over your field of vision

Diagnosis and treatment of myopia

An eye test will be able to tell you whether you are myopic. It’s generally advised to have an eye test every two years. However, should you notice any sudden changes in your vision or have any concerns then you can book a test sooner.

Can myopia be treated?

Myopia is easily corrected with prescription contact lenses or glasses. Some people also opt for refractive surgery though this is a more invasive procedure.

Corrective lenses

Depending on your prescription, you may need to wear your lenses or glasses at all times. You'll certainly need your glasses when you need very clear distant vision. For example, when watching the television, reading a board in class or driving.

If you’re short-sighted, the first number (sphere) on your prescription will be preceded by a minus sign (–). The higher the number, the more short-sighted you are.

Laser eye surgery

Laser eye surgery can reduce or eliminate short-sightedness but is an option that should be taken with caution. There are 3 main types of laser eye surgery:

1. Photorefractive keratectomy (PRK) – this procedure involves removing a small part of the cornea’s surface (the outer layer of cells known as the epithelium) and then using a laser to reshape the cornea.
2. Laser epithelial keratomileusis (LASEK) – the surface of the cornea is loosened with alcohol and a flap of tissue is lifted so that laser can go in and change the shape of the cornea. The flap is put back in place afterwards.
3. Laser in situ keratectomy (LASIK) – similar to LASEK, but a smaller flap of cornea is created.

Not everyone is suited to laser eye surgery, for example if you have diabetes, you may have abnormalities in your eyes which could be made worse by laser eye surgery.

It is not advisable to get laser eye surgery if you are pregnant or breastfeeding as your body will contain hormones which cause fluctuations in your eyesight, making the precision of the surgery challenging.

Any autoimmune conditions such as HIV or rheumatoid arthritis or other eye conditions such as glaucoma or cataracts can also cause problems with laser eye surgery.

Some patients experience a reoccurrence of their short-sightedness and in some cases, the condition becomes even worse than before surgery.

Your optician will usually advise that you wait until you’re at least 21 years of age before you consider this option. Before then, your eyes are still developing, and your myopia could stabilise. However, even if you are over 21, laser eye surgery should only be carried out if your glasses or contact lens prescription has not changed significantly over the last 2 years or more. Your eye care professional will be able to provide further advice.

What causes myopia?

Myopia occurs when the eyeball grows too long. When the eyeball is slightly too long, this prevents light from focusing on the retina (light-sensitive tissue) at the back of the eye. As a result, light rays focus on a point in front of the retina, rather than directly on its surface. This causes distant objects to appear blurred.

Myopia can also be caused by the cornea and/or lens being too curved for the length of the eyeball. In some cases, myopia is due to a combination of these factors.

The condition will typically start in childhood and usually worsens overtime, though some people find it stabilises with age.

Risk factors of myopia

There are certain risk factors which can increase the likelihood of myopia. These include genetics (especially in the East Asian community) and the environment.

Myopia can run in families, for example, if one of your parents has myopia, you are at a higher risk of developing myopia yourself. This likelihood increases if both parents are myopic. According to studies, lack of outdoor time also increases the risk of developing myopia.

Can myopia be prevented or controlled?

There are some options for preventing and controlling myopia that have mixed results depending on each patient.

One of the most popular ways of preventing or controlling short-sightedness is orthokeratology. This is a non-surgical procedure which requires that you wear rigid gas permeable contact lenses at night. The lens reshapes your cornea while you sleep and temporarily retains the shape throughout the day, giving you clearer vision.

Those who have minor myopia will have near perfect vision. In which case, they may only require an aid for activities such as driving at night or going to the cinema.

According to an article by Moorfields Eye Hospital, Bifocal or multifocal contact lenses (which let you see clearly both far and near without your own lens needing to focus) may also slow down myopia progression in children.

This article also noted that special eye drops, known as atropine eye drops, have been used in a study in Singapore amongst adults and have been shown to reduce the development of myopia.

Complications of myopia

Myopia can cause a whole wealth of complications especially if left untreated. Some of these problems are more severe whilst others are rather mild. The following are complications that one with near-sightedness may encounter:

• Eye strain – if left uncorrected, myopia may cause eye strain as you try to focus on objects, resulting in discomfort and headaches
• Safety risks – an uncorrected vision problem can risk your safety and others; for example, when carrying out activities such as driving
• Financial stress – corrective lenses/ glasses, eye exams and medical procedures can be costly causing financial stress for those with myopia
• Other eye problems – near-sightedness (if severe) can put you at risk of other eye problems including retinal detachment, cataracts, glaucoma, and damage in the central retina area (myopic macular degeneration)

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