Myopia vs. Astigmatism: What's the Difference?

Our eyes are wonderful, interesting, and intricate! While our eyes are growing as children, they may develop irregularities, like myopia or astigmatism.

Attending regularly scheduled eye exams is the best way to determine if you or your child has myopia or astigmatism. 

While both refractive errors are similar and can cause blurry vision, there are some key differences. The first step to understanding the difference between myopia and astigmatism is to understand how the eye works, and what those refractive errors look like.

Understanding the Cornea

Your eyes are made up of several layers and pieces that all work together to create your vision:

• Your cornea is the frontmost part of your eye. This transparent layer covers the iris (the coloured part of your eye) and pupil (the black centre in the middle of the iris), and allows light to enter your eye.
• Muscles in the iris are responsible for controlling the amount of light that enters the pupil. When it’s sunny, it should contract to restrict the amount of light; when it’s dark, it should widen to allow more light in.

Typically, the cornea is smooth and has an even thickness across the eye. 

The images that we see are comprised of light, which passes through the transparent cornea, into the pupil, and into the back of the eye (called the retina). 

Normal cornea:

• If the cornea is the correct smooth shape, the light will land just right on the retina, and you will have clear vision. 

Irregular cornea:

• If the cornea is too steeped, or misshapen, light can land improperly on the retina, causing blurry vision.

The cornea isn’t the only part of the eye that determines whether or not we see clearly! However, both astigmatism and myopia can be caused by an irregular cornea. But, myopia can be caused by other factors as well.

What Are the Symptoms of Myopia & Astigmatism?

There are several similarities in the symptoms of myopia and astigmatism, including:

• Blurry vision
• Eye strain
• Squinting
• Headaches
• Poor night vision
• Eye irritation

What Is Astigmatism?

Astigmatism causes blurry and distorted vision at several distances, and it is caused by irregularities in the cornea or lens.

Most people actually have some degree of astigmatism, but not everyone experiences blurry vision from it that needs vision correction. 

• Many people with a small amount of astigmatism go about their day without feeling its effects.
• Someone who has a lot of astigmatism may experience blurry and distorted vision, eye discomfort, and headaches.

Often, astigmatism develops alongside other refractive errors like myopia or hyperopia.

What Is Myopia?

Myopia, also called nearsightedness, causes objects in the distance to appear blurry. A slight myopia may cause objects far away to appear blurry, and a high myopia causes objects closer to appear blurry.

Myopia typically develops in childhood and continues to progress into adulthood. There are 2 reasons myopia might develop:

• The eye grows too long from front to back
• The cornea becomes too steep 

Myopia and astigmatism together can cause blurred vision at all distances. 

Can Astigmatism & Myopia be Cured?

Many people live with myopia, astigmatism, or both. Corrective lenses can often help you see clearly, but there is no cure for these refractive errors.

However, there are options available to help improve your vision.

Myopia Management

If myopia is diagnosed while your child’s eyes are developing, there are ways to control and slow  its progression:

• Atropine eye drops signal to the eye that it is time to stop elongating
• Myopia control glasses like MiyoSmart can help slow the progression of myopia in children
• Myopia control contact lenses, such as MiSight Contacts, are soft contact lenses that also slow myopia progression in children 
• Orthokeratology, also known as Ortho-K, involves the precision fitting of a contact lens to reshape the surface of the eye by a pre-determined amount to correct vision during sleep

Later in life, blurry vision due to myopia can be corrected with glasses or contact lenses. Many people are also candidates for laser eye surgery, which reshapes the cornea to bend (refract) light properly onto the retina.

Correcting for Astigmatism

Although there may not be ways to prevent astigmatism from becoming worse, there are ways to correct blurry vision caused by it:

• Corrective prescription glasses
• Corrective prescription contact lenses
• Laser and refractive surgeries

Orthokeratology, also known as ortho-k lenses, can help provide clear vision throughout the day without the need for corrective prescription glasses or contact lenses. These lenses gently reshape your eyes while you sleep, and are removed in the morning.

Diagnosing Myopia & Astigmatism

The only way to determine if you or your child has myopia or astigmatism is by visiting your eye doctor regularly. 

The team at Vivid Eye Care uses state of the art diagnostic technology to measure and assess your eyes. From there, our team can develop an individualized plan to help you or your child achieve the best vision possible.