Myopia is a common vision problem where close objects are seen clearly, but distant objects appear blurry.In individuals with myopia, the shape of the eye causes light rays to bend incorrectly, leading images to focus in front of the retina instead of directly on it.
What is Myopia?
Myopia, or nearsightedness, is an eye condition that causes distant objects to appear blurry while close objects are clear. The severity of myopia can range from mild forms, which may not require treatment, to severe forms that significantly impact vision.
Myopia can start in children between the ages of 6 and 13. It may worsen during teenage years when the body grows rapidly. The condition can also develop in adulthood.
What Causes Myopia?
The eye has two parts that focus images: the cornea and the lens. The cornea is the dome-shaped, transparent surface at the front of the eye, while the lens is a clear, convex structure behind it. In a normally shaped eye, these focusing elements have a smooth curvature, like the surface of a marble.
A smooth curve of the cornea and lens refracts incoming light sharply onto the retina at the back of the eye. However, if the cornea or lens is not smoothly curved, light rays do not bend correctly, resulting in a refractive error.
Nearsightedness typically occurs when the eyeball is longer than normal or when the cornea is overly curved. In these cases, light focuses in front of the retina instead of directly on it, causing distant objects to appear blurry.
Certain risk factors can increase the likelihood of developing myopia, including:
- Genetics: Myopia tends to be hereditary. If one parent has myopia, the likelihood of developing it increases. If both parents are nearsighted, the risk is even higher.
- Excessive reading or close-up work: People who read a lot, write frequently, or work at a computer may be at greater risk for myopia. Extended time spent playing video games or watching TV can also contribute to nearsightedness.
- Environmental factors: Some studies suggest that limited time spent outdoors may be linked to an increased risk of myopia.
What Are the Symptoms of Myopia?
Myopia symptoms in adults may include:
- Blurry vision when looking at distant objects.
- The need to squint or partially close the eyelids to see clearly.
- Eye strain and related headaches.
- Difficulty seeing while driving, especially at night.
Myopia is often detected in early childhood. Symptoms in a child with difficulty seeing distant objects can include:
- Persistent squinting.
- Sitting closer to the TV, movie screen, or front of the classroom.
- Appearing unaware of distant objects.
- Struggling to read the blackboard at school.
- Frequent blinking.
- Rubbing the eyes often.
Eye Problems Associated with Myopia
Adults with severe nearsightedness and untreated children are at higher risk for developing additional eye problems. The elongated shape of the eye can stretch and thin the tissues, leading to secondary eye conditions like:
- Strabismus: A common childhood issue where the eyes look in different directions.
- Amblyopia (Lazy Eye): A childhood eye condition where the vision in one eye does not develop correctly due to the brain favoring the other eye.
- Glaucoma: A serious eye disease characterized by increased eye pressure.
- Cataracts: A condition where the eye’s lens loses transparency.
- Retinal Detachment: A condition where parts of the retina separate from the blood vessels that provide oxygen and nutrients.
Myopia Test
If you or your child suspects myopia, it’s important to visit an eye doctor for a test. A vision test can confirm if there are issues with near or distant vision, and the doctor can prescribe glasses or contact lenses to correct the problem.
Testing for myopia involves measuring how the eyes focus light and determining the degree of optical lenses needed to correct vision. The test may include reading letters or symbols from a chart, such as the Snellen chart, to assess visual sharpness.
Vision is often measured using a fraction, like 20/40. The top number indicates the standard testing distance (20 feet), and the bottom number shows the distance at which a person with normal vision can read the same line.
A vision score of 20/40 means you must be 20 feet away to see what a person with normal 20/20 vision can see at 40 feet.
The eye doctor may use a phoropter, a device that places a series of lenses in front of the eyes, and a retinoscope to measure how the eyes focus light. This allows for determining the best corrective lenses.
If needed, eye drops can be used to prevent the eyes from adjusting focus during the test, particularly for patients who can’t respond verbally or when part of the eye’s focusing power is hidden.
How is Myopia Treated?
Myopia can often be corrected effectively with various treatments, including:
- Glasses or Contact Lenses: Glasses or contact lenses help focus light directly on the retina, making distant objects clearer. For most people with myopia, glasses are the first choice for treatment. Contact lenses may offer clearer vision and a wider field of view for some.Because contact lenses are worn directly on the eyes, they require careful use to maintain eye health. Depending on the severity, glasses or contacts may be worn all the time or only for specific activities.
- Laser Eye Surgery: Laser surgery can reshape the cornea to correct the eye’s curvature. This procedure is generally not recommended for children because their eyes are still developing.
- Artificial Lens Implants: Surgically implanted lenses can permanently correct focus.
- Corneal Implants: INTACS are plastic corneal rings that adjust the cornea’s shape. These implants can be left permanently or adjusted if necessary.
Frequently Asked Questions
Is There a Cure for Myopia?
Yes, myopia can be corrected. Vision problems can be addressed using glasses or contact lenses. For those seeking a permanent solution, laser eye surgeries like LASIK or PRK are available. These procedures correct refractive errors, resulting in clear vision.
What is Astigmatic Myopia?
Astigmatic myopia is a condition where both astigmatism and myopia occur together. In astigmatism, the cornea is irregularly shaped, causing blurred vision at both near and far distances. Myopia makes distant vision unclear. When combined, the vision impairment can be more complex.
How Far Can a Person with Myopia Not See?
People with myopia cannot see distant objects clearly; how blurred they are depends on the degree of myopia. Mild myopia allows for some mid-distance clarity, while severe myopia causes everything beyond close-up objects to be blurry. Untreated myopia can also impact night vision.