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Astigmatism vs. Myopia vs. Presbyopia

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An optometrist explaining the results of an eye exam to her patient using the aid of an eye diagram.

Your eyes are intricate and delicate organs that provide you with the gift of sight. Unfortunately, sometimes things can go wrong. An optometrist can uncover refractive errors during a comprehensive eye exam and help you understand their meaning. Some of the most common refractive errors are astigmatism, myopia, and presbyopia. Although these conditions may sound similar, each has unique causes and characteristics.

Astigmatism is caused by an irregularly shaped cornea or lens, myopia (nearsightedness) is caused by an elongated eyeball or curved cornea, and presbyopia (farsightedness) is a natural age-related change in the lens. 

Treatment for each condition also varies but usually involves prescription glasses or contact lenses.

Structures of the Human Eye

The human eye comprises several parts, all working together to produce vision. The cornea at the front of the eye helps to focus light through the lens and onto the retina.

The retina is a layer of specialized cells at the back of the eye that acts like a camera sensor, converting light into electrical signals that are sent to the brain via the optic nerve. The brain uses the information from the eyes to create the images we see, allowing us to perceive the world in incredible detail and color.

As light enters the eye, it’s refracted, or bent, by the cornea and lens before being focused onto the retina. Light may not focus correctly if your eye, cornea, or lens are irregularly shaped. Instead, it could land in front, behind, or scattered across the retina, resulting in a refractive error.

What Is Astigmatism?

Astigmatism occurs when the cornea or the lens is shaped irregularly. Ideally, the cornea should be spherical, like a basketball. However, in those with astigmatism, the cornea is shaped more like a football, which leads to refractive errors. This can make your eyesight appear fuzzy or blurred at any distance.

Symptoms & Causes of Astigmatism

A woman in a brightly lit living room suffering from a headache. Astigmatism-myopia-presbyopia

The most common symptom of astigmatism is blurry vision. Depending on the severity of the case, the blurriness may occur at any distance, making it difficult to read, drive, or see anything clearly. Other symptoms to watch out for include:

  • Eye fatigue
  • Headaches
  • Light sensitivity
  • Squinting in an attempt to see clearly

Astigmatism is usually inherited from one’s parents and is present from birth, but it could develop later in life from:

  • Eye disease
  • Eye injuries
  • Eye surgery

Astigmatism Treatments

While it can be a frustrating and uncomfortable condition, astigmatism is treatable. Treatments could include glasses or contact lenses specially designed for people with astigmatism. If you prefer not to wear glasses or contacts, you can undergo corrective laser eye surgery to reshape your cornea.

What Is Myopia?

Myopia, also known as nearsightedness, is a common eye condition affecting millions worldwide. It’s a refractive error that occurs when the eyeball is too long, or the cornea is too curved, causing light rays to focus in front of the retina instead of onto it. This results in blurred vision when looking at distant objects, while objects up close appear clear.

Symptoms & Causes of Myopia

Myopia typically presents in school-aged children, affecting their learning and growth. Sometimes behavioral problems and learning difficulties can be traced back to an inability to see clearly. And children’s eyes are still growing. So if left untreated, myopia could worsen until it stabilizes (usually around 20).

A big problem for kids with myopia is that recognizing it can be challenging. These are some signs that your child may have myopia:

  • Frequent blinking
  • Complaints of fatigue or blurriness
  • Shying away from reading
  • Covering one eye
  • Lack of focus or attention

Experts aren’t sure exactly what causes myopia, but genetics are known to play a role. Other factors include excessive screen time, close work, and spending less time outdoors.

Myopia Treatments

Much like astigmatism, myopia can be corrected with eyeglasses, contact lenses, or laser eye surgery for adults.

However, once the damage from myopia is done, it can’t be reversed. Since high myopia can increase the risk of eye disease, slowing myopia’s progression can help preserve eye health. Optometrists use myopia management to potentially slow the condition and help ease the burden on children’s vision.

What Is Presbyopia?

Presbyopia is a natural part of the aging process and occurs when the lens inside your eye loses its flexibility. As a result, it becomes less effective in helping you focus on objects up close. This condition usually occurs when people are in their early to mid-40s and gradually worsens over time.

Symptoms & Causes of Presbyopia

Usually, the eye’s lens changes shape as need be, focusing light on the retina for far and near vision. When you age, it hardens and can’t focus light as well as it once could. This makes nearby objects blurry, while distant objects remain clear.

Before a person develops presbyopia, they may have been able to see close objects clearly and with ease. However, the condition can affect daily activities and cause discomfort when typical tasks require focus close things, such as reading, sewing, or working on a computer.

Treatments for Presbyopia

People with presbyopia may opt for eyeglasses or contact lenses to help them read. If you already wear glasses (such as for astigmatism or myopia), bifocals, trifocals, and progressive lenses are popular choices for presbyopia as they can improve vision at both near and far distances.

The Right Care for Your Unique Eyes

No matter the vision problem, the goal remains clear and comfortable sight. And the first step is knowing what’s affecting you. Optical Illusions uses high-tech diagnostic equipment to examine your eyes and determine your prescription.

If you or someone in your family is living with a refractive error, book an appointment at one of our 4 convenient locations today! Our team can help you find fashionable frames and offer expert advice for managing your condition.

Written by Dr. Will To

Dr. William To has multiple years of healthcare experience providing design-based ocular care, with an optometric emphasis in Pediatrics, Dry Eye Therapy, and Ocular Surface Disease.

He graduated from UC San Diego with a Bachelor’s in Human Biology and a minor in Psychology and earned his Doctorate in Optometry from Western University of Health Sciences. Dr. Will is regularly invited to several Optometric Conferences and Colleges of Optometry each year to lecture to his colleagues and students, having given over 100 lectures and written several published editorials.

When he’s not caring for his amazing patients, Dr. Will enjoys traveling every chance he gets. As a Bay Area native, he has taken on leadership roles both in the local community and beyond, serving as the President of the Santa Clara County Optometric Society and on several California Optometric Association and American Optometric Association committees. He is actively involved with a variety of community outreach and social programs.

Dr. Will is an avid Golden State Warriors and 49ers fan.

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